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Extracting Nuclear DNA from Hair Shafts is a “Hairy” Situation

Law enforcement officers collect a variety of evidence at crime scenes, such as bullet fragments, weapons, narcotics, and fingerprints. In addition, police gather body fluids, skin cells, bones, and hairs, hoping that one or more of those substances will contain a suspect’s DNA.

But where, you might ask, is the DNA located? Well, it’s certainly not doing the backstroke in the pool of blood that leaked from a fallen victim of a gunshot. Instead, the DNA evidence sought by police—nuclear DNA—is contained within the nuclei of cells.

Cells, the Home of Nuclear DNA

All cells in our body are made up of a cell wall (cell membrane), cell fluid (cytoplasm) and a nucleus, with the exception of red blood cells and platelets. Since neither of latter two have a nucleus they do not contain DNA.

Nuclear DNA is made up of genetic material from our fathers and mothers. The nucleus of each cell contains a pair of chromosomes—, one from each parent.

Each cell typically contains 23 pairs of chromosomes, for a total of 46. Twenty-two of the pairs are called autosomes, and they look identical in both male and female humans. The 23rd pair are the sex chromosomes and they are distinctly different between males and females. Females have two copies of the X chromosome. Males have one X and one Y chromosome.

As evidence in criminal matters, DNA serves a dual purpose—identifying an individual as the source of the DNA found on an evidence item, or to exclude the individual as the contributor of the collected DNA evidence.

Now, we’ve briefly and generally discussed that DNA lives in cells, and those cells are where scientist go to retrieve the DNA needed for testing. And we know that DNA is readily found in body fluids, skin cells, bones, and for many years it was believed that testing hair for DNA was only possible if the bulb/root at the base of the hair shaft was intact. This was so because the keratinization process that creates the hair shaft during its growth often breaks down (lyses ) cell membranes.

DNA IS present, though, in hair shafts, but in small quantities. It’s quite short and fragmented, which is similar to DNA found in ancient remains. So yes, like testing DNA found remains of wooly mammoths and other beings and bits and bobs from long ago, it is possible to isolate nuclear DNA from rootless human hair samples.

In fact, to make this possible, a company called InnoGenomics uses a magnetic bead extraction system that’s specifically optimized for the process of capturing low-level, highly degraded DNA.

By combining InnoGenomics’ two DNA typing kits together—InnoXtract and InnoTyper 21 (IT21), the isolation and typing of nuclear DNA from rootless hair shafts is quite achievable. And, the process is compatible with Capillary Electrophoresis (CE) instruments, such as Promega’s Spectrum CE System.

So yes, crime writers, the heroes of your tales have a tool to add to their crimefighting toolboxes, because it is indeed possible to obtain nuclear DNA from hair shafts.

DNA Testing in General

The first step in the testing process is to extract DNA from the evidence sample. To do so, the scientist adds chemicals to the sample, a process that ruptures cells. When the cells open up DNA is released and is ready for examination.

Did you know it’s possible to see DNA with the naked eye? Well, you can, and at the bottom of this page you’ll learn how see the DNA that you, in your home kitchen, can extract DNA from split peas.

After DNA is extracted it’s then loaded into wells inside the genetic analyzer.

Scientist placing a well plate containing 96 individual wells into a genetic analyzer. Below right in photo is a closeup of a well plate.

Electric current separates the DNA, sending it from the wells through narrow straw-like tubes called capillaries. During its journey through the analyzer, DNA passes by a laser. The laser causes the DNA loci (a gene’s position on a chromosome) to fluoresce as they pass by, which allows a tiny camera to capture their images.

The image below shows DNA’s path from the wells through the capillaries past the laser.

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At the end of the testing, the equipment produces a graph/chart called an electropherogram, a chart/graph of peaks and valleys that precisely pinpoints where genes are located.

An allele is a term that describes a specific copy of a gene. Each allele occupies a specific region on the chromosome called a gene locus. A locus (loci, plural) is the location of a gene on a chromosome.

Peaks on the graph depict the amount of DNA strands at each location (loci). It is this unique pattern of peaks and valleys that scientists use to match or exclude suspects.

 

The image below, as ominous as it appears, is an electropheragram showing the DNA of a strawberry.

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Serial Killer Challenges DNA Results

*The following text regarding the appeal from serial killer Timothy W. Spencer, The Southside Strangler,” is from the US Court of Appeals for the Fourth Circuit. Spencer’s case was the first in the U.S. based on DNA evidence that resulted in the death penalty. I served as a witness to Spencer’s execution. Click here to read about my experience.

“Timothy W. Spencer, Petitioner-appellant, v. Edward W. Murray, Director, Respondent-appellee, 5 F.3d 758 (4th Cir. 1993)

US Court of Appeals for the Fourth Circuit – 5 F.3d 758 (4th Cir. 1993)Argued Oct. 28, 1992. Decided Sept. 16, 1993

J. Lloyd Snook, III, Snook & Haughey, Charlottesville, VA, argued (William T. Linka, Boatwright & Linka, Richmond, VA, on brief), for petitioner-appellant.

Donald Richard Curry, Sr. Asst. Atty. Gen., Richmond, VA (Mary Sue Terry, Atty. Gen. of Virginia, on brief), for respondent-appellee.

Before WIDENER, PHILLIPS, and WILLIAMS, Circuit Judges.

OPINION

WIDENER, Circuit Judge:

Timothy Wilson Spencer attacks a Virginia state court judgment sentencing him to death for the murder of Debbie Dudley Davis. We affirm.

The gruesome details of the murder of Debbie Davis can be found in the Supreme Court of Virginia’s opinion on direct review, Spencer v. Commonwealth, 238 Va. 295, 384 S.E.2d 785 (1989), cert. denied, 493 U.S. 1093, 110 S. Ct. 1171, 107 L. Ed. 2d 1073 (1990). For our purposes, a brief recitation will suffice. Miss Davis was murdered sometime between 9:00 p.m. on September 18, 1987 and 9:30 a.m. on September 19, 1987.

Miss Davis was murdered sometime between 9:00 p.m. on September 18, 1987 and 9:30 a.m. on September 19, 1987. The victim’s body was found on her bed by officers of the Richmond Bureau of Police. She had been strangled by the use of a sock and vacuum cleaner hose, which had been assembled into what the Virginia Court called a ligature and ratchet-type device. The medical examiner determined that the ligature had been twisted two or three times, and the cause of death was ligature strangulation. The pressure exerted was so great that, in addition to cutting into Miss Davis’s neck muscles, larynx, and voice box, it had caused blood congestion in her head and a hemorrhage in one of her eyes. In addition her nose and mouth were bruised. Miss Davis’s hands were bound by the use of shoestrings, which were attached to the ligature device. 384 S.E.2d at 789.

Semen stains were found on the victim’s bedclothes. The presence of spermatozoa also was found when rectal and vaginal swabs of the victim were taken. In addition, when the victim’s pubic hair was combed, two hairs were recovered that did not belong to the victim. 384 S.E.2d at 789. The two hairs later were determined through forensic analysis to be “consistent with” Spencer’s underarm hair. 384 S.E.2d at 789. Further forensic analysis was completed on the semen stains on the victim’s bedclothes. The analysis revealed that the stains had been deposited by a secretor whose blood characteristics matched a group comprised of approximately thirteen percent of the population. Spencer’s blood and saliva samples revealed that he is a member of that group. 384 S.E.2d at 789.

Next, a sample of Spencer’s blood and the semen collected from the bedclothes were subjected to DNA analysis. The results of the DNA analysis, performed by Lifecodes Corporation, a private laboratory, established that the DNA molecules extracted from Spencer’s blood matched the DNA molecules extracted from the semen stains. Spencer is a black male, and the evidence adduced at trial showed that the statistical likelihood of finding duplication of Spencer’s particular DNA pattern in the population of members of the black race who live in North America is one in 705,000,000 (seven hundred five million). In addition, the evidence also showed that the number of black males living in North America was approximately 10,000,000 (ten million). 384 S.E.2d at 790.”

How You Can Easily Extract DNA From Split Peas!

Easy “pea-sy” DNA extraction

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Sir Alec Jeffreys and the DNA Testing of Over 5,500 Men, All to Catch a Single Killer

As the result of a DNA experiment on September 10, 1984, Alec Jeffreys discovered the technique of genetic fingerprinting. At the time, Jeffreys worked as a researcher and professor of genetics at the University of Leicester.

At 9.05 a.m. that September morning, the life of Alec Jeffreys changed forever, as did the entire world of criminal investigations and paternity cases. It was, as Jeffreys calls it, his “eureka moment.”

Jeffreys’ DNA fingerprinting was first used in a police forensic test to identify the killer of two teenagers, Lynda Mann and Dawn Ashworth. The two young women had been raped and murdered in 1983 and 1986 respectively.

A 17-year-old boy with learning difficulties—Richard Buckland—confessed to one of the killings but not the other.

The detective in charge of the case was skeptical of Buckland’s odd confession and his involvement, or lack of, in the second murder. The detective recently learned of Alec Jeffreys’ breakthrough discovery and figured, well, he thought he had nothing to lose so he contacted the scientist to ask if he thought his new technique could prove that Buckland had murdered both young women. The top cop was in for a surprise.

Jeffreys agreed to see what he could do and extracted DNA from Buckland’s blood and from semen taken from the dead girls’ bodies. Then he compared them, immediately seeing that the girls had been raped by the same man. However, Buckland’s DNA was completely different. He had not been in contact with either of the victims.

Police had the wrong man and, after three months in jail, Buckland was released from custody.

Detectives then came up with a wild plan. They decided to set up an operation to gather the DNA of every man in the area. Eight months later, after eight months of sampling and testing, 5,511 men had given blood samples. Only one man had refused to cooperate and after testing all those samples, still no match to the semen samples collected from the victims.

Among the over 5,000 men who provided blood samples was a 27-year-old baker and father of two young children named Colin Pitchfork. Three years earlier, police had questioned him about his movements on the evening that Lynda had been murdered. But nothing came of it.

In August 1987, over a year after the killing of Dawn, one of Colin Pitchfork’s coworkers was in a local pub having drinks with friends and somehow Pitchfork’s name entered their conversation. One member of the group, a man named Kelly, admitted that he’d impersonated Pitchfork and took the blood test on his behalf. Kelly told the group that Pitchfork asked him to do this for him because he’d already taken the test for another friend who had a criminal conviction and was afraid of taking the test a second time. So Kelly agreed. Pitchfork then doctored his passport by inserting Kelly’s photograph in place of his own and then drove Kelly to the test site where he waited outside while Kelly’s blood was drawn.

A few weeks later, one of the people in the pub passed along the information to a local policeman. Kelly was arrested and he confessed to the impersonation. By the end of the work day Pitchfork was also in custody. One of the detectives who questioned the Pitchfork asked him, “Why Dawn Ashworth?”

Pitchfork nonchalantly replied, “Opportunity. She was there and I was there.”

So this is how it all started. A drop of blood and a semen sample met a small electrical charge (see images of the process below). The result was a few blips on an x-ray film that resembled a grocery store product bar code. Each of us has one of those bar codes that is unique to us. And it was Professor Sir Alec Jeffreys discovered the secret to finding and reading those codes.

I knew of this incredible story and was reminded of it when Denene and I recently watched Code of a Killer, the television mini-series based on these events.

Joseph Wambaugh told the story in his 1989 best selling book The Blooding: The True Story of the Narborough Village Murders.

Finally, after watching the TV show I recommend taking a moment or two to watch Professor Sir Alec Jeffreys lecture about his discovery, and you may do so below.

DNA testing by electrophoresis (gel testing) … the process

Weighing the agar gel.

Mixing the gel with water.

Gel in chamber.

Forensic Facts

Injecting DNA into the gel.

Attaching electrodes to the chamber.

Introducing electric current to the gel.

Completed gel is placed onto an illuminator for viewing.

 Gel on illuminator.

*My thanks to Dr. Stephanie Smith for allowing me to hang out in her lab to take the above photos.

Completed gel showing DNA bands

DNA bands

DNA Facts

  • DNA is the acronym for deoxyribonucleic acid.
  • DNA is a double-helix molecule built from four nucleotides: adenine (A), thymine (T), guanine (G), and cytosine (C).
  • Every human being shares 99.9% of their DNA with every other human.
  • If you placed all the DNA molecules in your body end to end, the DNA would reach from the Earth to the Sun and back over 600 times!
  • Humans share 60% of our genes with fruit flies.
  • We share 98.7% of our DNA in common with chimpanzees and bonobos.
  • If you could type 60 words per minute, eight hours a day, it would take approximately 50 years to type the human genome.
  • Humans share 85% of our DNA with a mouse.
  • We also share 41% with a banana.
  • According to a study conducted at Princeton University, all humans, including Africans likely have a bit of Neanderthal in our DNA. This was a fascinating discovery since until these findings were released in 2020 it was believed that Africans did not have Neanderthal DNA.
  • Friedrich Miescher discovered DNA in 1869. However, it was not until 1943 that scientists came to understand that DNA was the genetic material in cells.
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Cops Use Mosquitos to Solve Murders: Bandit Bagged By Bug

A Murder.

No known suspect.

Evidence collection.

Let’s run down our checklist to be certain we’ve gathered everything because, as you all know, the crime-solving clock is ticking nonstop and valuable time is slipping away, and so is the killer.

Let’s see, we’ve got fibers, bullet casings, fingerprints, weapon, clothing, glass fragments, shoes, shoe and tire impressions, photographed everything, and … “Hey, somebody catch that mosquito. We need to take it in for questioning. It may know something.”

CSI Frank the Fingerprint Guy rushes out to the official CSI van to grab the Handy-Dandy Mosquito-Catching Net 700 (the model one-up from the 600 series) and sets out on the mission of snagging the elusive biting bug.

It’s on the ceiling. Now the wall by the light switch. Back on the ceiling, on the curtains, the window, the blinds, the ceiling again, and now … Got It!

Frank the Fingerprint Guy gently transfers the bloodsucker into a container that’s safe for transport and then off they go to the lab to see what this little guy can tell them about the crime of murder. Who knows, the insect may even be able to provide the name of the murderer.

That’s right, mosquitos are indeed able to spill the beans about a criminal’s identity, and here’s how.

First, what is it that so many jurors like to hear about? Yep, DNA.

You can talk until you’re blue in the face about all the fancy footwork and door-knocking and interviews and bullet trajectory, and more, but that’s not what makes jurors salivate like they do when they hear you found the suspect’s DNA at the crime scene. That’s the golden goose. The bestest prize what there ever was. DNA. DNA. DNA. Give ’em D-freakin’-N-A!

And what is that mosquitos enjoy more than buzzing around the ears of evening picnickers? Yes, feeding on human blood! And what’s found in human blood? Yes, DNA! Ding, ding, ding, we have a winner!

Scientists have learned that blood extracted from mosquitoes remains viable for DNA analysis up to two days after feeding. Therefore, a savvy crime scene investigator could save the day by simply catching mosquitos found flitting about at crime scenes.

A quick DNA test of the blood found in the belly of the bug could quite easily reveal the name of the killer (if his information is in the system), and how cool would it be to bring in Mr. I. Done Kiltem and notice he has a fresh mosquito bite on his cheek? I know, right?

At the very least, the DNA test could tell police who was at the crime scene. Might not be the killer’s blood in the bug’s belly, but it could be that of an accomplice or witness or someone who could help establish a timeline. Either way, Bug Belly Blood could prove to be a bit of extremely valuable evidence.

Imagine the headline …

Bandit Bagged By Bug Belly Blood

Unfortunately, the window for DNA testing of blood in a mosquito’s gut is limited to two days because the blood is completely digested by day three.

 

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Twisting Your Twisted Tales: Twins Have Identical DNA, Except When They Don’t …

 

We all know how valuable DNA testing is in the worlds of paternity testing and crime-solving. In fact, DNA testing is so accurate that we’re able to determine, with just a mere microscopic fleck of doubt, the identity of a long-lost father, or mother, a name associated with remains found in areas of disaster, and we’re able to learn the names of perpetrators of crimes of various types. All from a tiny speck of blood, tissue, other body fluids, etc.

Remember, every cell in the human body has DNA except red blood cells. Therefore, almost anything a suspect handled could contain DNA. This is why crime-scene investigators locate and collect items they think a suspect may have touched—cigarette butts, bloody clothing, weapons, paper, drinking glass, etc. The evidence is then turned over for testing to a forensic lab and its scientists.

The first step in the testing process is to extract DNA from the evidence sample. To do so, the scientist adds chemicals to the sample, a process that ruptures cells. When the cells open up DNA is released and is ready for examination.

The rest of the process is pretty straightforward and not all that complicated. DNA is loaded into a genetic analyzer that produces a readout that’s specific to the individual who left the evidence (skin, blood, tissue, semen, saliva, etc.).

This is all well and good EXCEPT when twins are involved, because twins have identical DNA. And, when two people have the same DNA and one of them commits a murder, well, without other evidence to validate the charges it’s difficult to prove which twin was at the scene and which was not. A near perfect crime?

Well, scientists at University of Huddersfield, located in Huddersfield, West Yorkshire, England, have devised a means distinguishing slight differences—mutations—between the DNA of identical twins.

DNA methylation, simply put, is the molecular mechanism that switches various genes on and off. Therefore, when one twin is, for example, a lifeguard who spends much of daily life in the sun but her identical twin does not, the difference in lifestyles will cause changes in the methylation status of the DNA. These changes in the DNA methylation status of the sun-loving sibling are the subtle changes that sets the twins apart. The same is true when one twin is a smoker and the other lives a tobacco-free life, and so on.

The technique used—high resolution melt curve analysis—subjects the DNA samples/evidence to increasingly high temperatures until the hydrogen bonds break. This breaking point is known as the “melting temperature.”

Again, to simplify, the difference between the melting temperatures establishes the difference between two identical twins. So, the post-methylated-tested DNA can indeed point investigators to the guilty twin.

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So there you have it, writers, a new twist for your twisted tales.

 

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An April Fools Crime-Solving Puzzle: How Sharp Is Your Protagonist?

An April Fools crime solving puzzle

 

Detectives Slim N. None and Frank Lee Iduncare caught the case of their careers when Captain I. Giterdun assigned them to investigate the murder of one of Savannah’s most popular ghost tour managers, I.C. Spooks.

The two top cops arrived on the scene and found Ms. Spooks’ body (her friends call her Ida, they’d learned) lying in a cobblestone alley just off River Street, near the entrance to the Gulp ‘Em Down Oyster Bar and Rot Gut Drink Emporium.

No witnesses and no obvious clues. No weapon and no sign of injury or open wounds. Not even so much as a chipped fingernail. No footprints on the stones. Not a single thing to go on. Well, except for a tiny dot of something reddish brown on the tip of the victim’s right index finger. None said the drop certainly looked like blood. To be certain, though, they’d have to wait for the autopsy report, hoping the M.E. would come up with the impossible. In the meantime, the detectives did what they do best…knocked on doors and asked a lot of questions. In other words, they pestered people until they either talked or slammed the door in the eager faces of the two detectives. The latter being the more common occurrence.

Turns out that it was DNA that solved the Spooks murder case. Below are the possible findings of Savannah detectives and medical examiner Y. N. Sizion. Nine of the things listed could be true scenarios. One, however, is not. Do you have what it takes to spot the April Fools finding? Well, let’s see if your protagonist really knows her DNA, or, if her knowledge was gained from watching Castle reruns.

The List

1. After developing a list of ten perfectly possible perpetrators, a positive match to suspect number ten was discovered by matching DNA from the crime scene to the DNA found in a recently-formed dental mold (the suspect was fitted for a new crown the day prior to the murder).

2. The suspect was identified by matching DNA found at the crime scene to DNA found on the mouth opening of a seriously shrunken ski mask located in a overflowing and lopsided clothes basket in the suspect’s apartment.

3. The medical examiner found a single foreign hair (no root) lodged deep in the throat of the victim. DNA found in the hair matched the DNA of one of the suspects.

4. The killer had forced oral copulation on the victim prior to her death. The victim’s DNA matched DNA swabbed from the suspect’s “private part.” The comparison was made several hours after the offense.

5. DNA found on a cigarette butt lying near the victim’s body matched the DNA of one of the ten suspects. Faced with the DNA evidence linking him to the crime scene, he, suspect number seven, confessed to the murder.

6. Detective Iduncare found a crumpled postcard wedged between the north side trolley rail and a loose cobblestone. DNA found on the back of the card’s postage stamp was a positive match to suspect number four.

7. None and Iduncare were pleased and positively elated when the lab identified suspect number five by matching the DNA found at the crime scene to the DNA extracted from the suspect’s red blood cells.

8. A scientist from the lab called Iduncare to deliver the news he’d been waiting to hear…yes, the scientist had indeed discovered DNA on Spooks’ body, but what she’d found was a mixture, meaning there could have been more than one suspect. She went on to say that since her discovery was a mixture, she would not and could not positively include or exclude any one person as a suspect in the crime.

9. Detective None interviewed the Gulp ‘Em Down bartender and learned the poor woman had a nasty cold. She also said that, out of curiosity, she’d walked over to have a look at the body where she engaged in one of the worst coughing and sneezing fits of her entire 27 years on the planet. And, yes, she probably sprayed the corpse with quite a bit a spittle in the process. “That wasn’t a problem, was it?” the pink and green-haired woman asked while using a wadded bar napkin to mop the end of her dripping nose. Detective None learned from the folks at the lab that blowing cold remnants on a dead body could indeed compromise whatever DNA they found.

10. During the testing, scientists found the DNA of several people on the victim’s body, including that of None and Iduncare, who should have worn gloves while processing the crime scene.

After the lab results finally came back, and all was sorted through and pawed at by a team of prosecutors, None and Iduncare were finally able to slap the cuffs onto the wrists of their suspect(s).

And, future ghost tours were proud to boast of a brand new spirit, the recently departed I.C. Spooks, whose her ghost could often be seen peering out at tourists from behind the windows of various businesses and storefronts along the riverfront.

*Top photo – Savannah-Chatham Metro Police Department

* Bottom photo – I.C. (Ida) Spooks

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DNA Testing: Is It Really All That Complicated?

DNA Testing

DNA testing is a great tool for law enforcement. It’s been used to convict criminals in a wide variety of cases, including, murder, rape, robbery, kidnapping, and even blackmail. DNA testing is also used as a means to exonerate the innocent.

DNA testing is pretty darn accurate as long as investigators and scientists handle crime-scene evidence properly, without contaminating it. Something as simple as sneezing on a piece of evidence can ruin a detective’s chances of solving a homicide.

Every cell in the human body has DNA except red blood cells; therefore, almost anything a suspect handled could contain DNA. Even a hairbrush or hat can contain a murderer’s dandruff. Keeping that in mind, crime scene investigators locate and collect items they think a suspect may have touched—cigarette butts, bloody clothing, weapons, paper, drinking glass, etc. The evidence is then turned over to a forensic lab and its scientists for testing.

At the lab, items are logged in and then they wait on a shelf until their time “on the bench” rolls around. Could be days, weeks, or even months. Wait time depends on the backlog of cases. Of course, some high-profile or other urgent cases warrant a move to the front of the line.

The time to conduct the actual testing is pretty quick, not including prep time, no troubles with equipment, etc.

The first step in the testing process is to extract DNA from the evidence sample. To do so, the scientist adds chemicals to the sample, a process that ruptures cells. When the cells open up DNA is released and is ready for examination.

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DNA is actually visible to the naked eye. The slimy glob in the center of the circle below is DNA.

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DNA is tested in devices like the one below. They’re called genetic analyzers.

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DNA is loaded into wells inside the genetic analyzer. There are 96 wells in the gray, rectangular block shown below (inside the analyzer).

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An electric current separates the DNA, sending it from the wells through narrow straw-like tubes called capillaries. During its journey through the analyzer, DNA passes by a laser. The laser causes the DNA loci (a gene’s position on a chromosome) to fluoresce as they pass by, which allows a tiny camera to capture their images.

The image below shows DNA’s path through the genetic analyzer.

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Capillaries

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Doctor Smith points to the row of eight capillaries, one for each well in the corresponding line of wells (12 rows of 8 wells).

At the end of the testing, the equipment produces a graph/chart called an electropherogram.

Peaks on the graph depict the amount of DNA strands at each location. It is this unique pattern of peaks and valleys that scientist use to match or exclude suspects.

Or, in the case of paternity testing, to include or exclude someone as a parent.

The image below is an electropheragram showing the DNA of a strawberry.

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Another method of obtaining DNA results is to “run a gel.” This procedure, like it’s modern day counterpart the genetic analyzer, separates and measures DNA strands.

DNA testing by electrophoresis (gel testing)

Weighing the agar gel (powder at this stage).

Mixing the gel with water.

Gel in chamber. After mixing with water the gel “sets” to the consistency of Jell-O.

Gels are like flat sponges, with many tiny holes, nooks, and crannies.

Injecting DNA into the gel. Pre-formed wells are in place to receive the DNA.

Attaching positive and negative electrodes to the chamber.

Electrical current is the force that causes the DNA strands to move across and through the gel.

Introducing electric current to the gel.

Short strands move quicker and farther than longer strands. Strands of the same or similar lengths wind up grouped together.

Staining the DNA groups makes them visible on the gel. After staining, the completed gel is placed onto an illuminator for viewing.

Gels are then photographed for later use, possibly in criminal or civil trials.

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*Above and below photos courtesy of world renowned DNA expert Dr. Dan Krane. Some of you will remember Dr. Krane from his wonderful presentation at the WPA.

DNA is introduced to the testing equipment which then moves through the processes to produce a visible result. It’s not a series of steps where someone could stop, take a look at the incomplete process, and then make a guess as to whether or not someone could be included or excluded as a suspect.

It’s not until the entire process is complete that experts will be able to compare DNA results—suspect DNA to DNA found at a crime scene. Or, to compare test results to human DNA for the purpose of excluding someone as a suspect. There is no midway “make-a-guess-and-leak-to-the-press” point. When it’s done, it’s done.

Below are the DNA test results of a rape victim and two suspects. Obviously, neither of the suspects’ DNA matches that of the victim. However, suspect number two is a perfect match for the DNA found on the victim’s body.

New Picture

It’s true that excluding someone as a suspect is an often quicker process than identifying the bad guy. This is so because officers already know the identities of some of these people and have collected their DNA samples for testing/comparison.

However, the killer’s identity is probably an unknown at this point because police have not been able to obtain “matchable” evidence from the actual perpetrator. Therefore investigators must begin their quest for a DNA match by conducting good old-fashioned police work—interviewing witnesses and suspects, lifting fingerprints, collecting and identifying physical evidence, and knocking on doors and talking to neighbors, friends, family, etc. Whatever it takes to lead them to the killer and his DNA.

Of course, there’s always the possibility that the killer’s DNA is already tucked away in a computer database, such as CODIS. A quick run-through in the computer system will bring up several close matches, or a positive ID. Remember, though, if the DNA is not in the database investigators must rely on basic investigative skills (please re-read the paragraph preceding this one).

In short, DNA testing is, well, DNA testing. There is no point in the middle of the of the procedure that would allow investigators to exclude anyone as a suspect. The process must run its course to be of use.

*My thanks to Dr. Stephanie Smith for allowing me to hang out in her lab to take the above photos.

 

Did you know DNA is used to…

Determine pedigree in livestock.

Authenticate caviar and wine.

Identify endangered and protected wildlife species (to prosecute poachers).

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Guilty, Or Not?: Skip The Polygraph and Reach For The Ice Cream

Guilty or not

 

Nearly two decades have passed since I watched serial killer Timothy Spencer, The Southside Strangler, die in the electric chair. I knew the details of the case, including that Spencer had been released from prison after serving three years on a ten year sentence for burglary. His release from prison, however, was conditional. He was to live in a state-run halfway house for a predetermined amount of time. The year was 1984. DNA testing was not yet available to law enforcement.

Spencer was allowed to “check out” of the halfway house on weekends. I assume he, like others serving part of their sentences in halfway houses, was allowed to go out to work or search for employment, attend religious services and AA and NA meetings, see a doctor or dentist, shop for clothing, and leave the halfway house on weekends.

During Spencer’s weekends away from the halfway house is when he added other, unauthorized, stops to his schedule. During an eleven week span Spencer visited quiet suburban neighborhoods where broke into the homes of four women. In each of the break-ins, he attacked the women, bound their hands, and then brutally raped and killed them. His murder weapon in three of the four cases was a cleverly designed ligature that tightened more and more as the victim struggled. Detectives weren’t able to locate a single shred of discernible evidence at either of the crime scenes, but they collected any and everything they thought might help locate the killer, including samples of the murderer’s semen.

Finally, a relentless investigator named Joe Horgas heard that British police had identified a killer through DNA matches of blood and semen. Horgas then contacted a lab that specialized in DNA testing and they agreed to help. Horgas soon received the news he’d been hoping to hear—Spencer’s DNA matched the semen samples collected by detectives. Spencer was then arrested, tried, and convicted. It was four years after the first rape and murder.

Timothy Spencer was the first killer in the U.S. sentenced to die based on DNA evidence. I watched him die, and believe me, death by electrocution is far from being a passive exit from this world. A man moaning and breathing hard during lethal injection has nothing on those who’ve ridden Old Sparky on the journey to wherever it is they go after all is said and done. But it is what it is.

Now, back to Spencer and his last day alive on this planet. I mentioned earlier that he showed no signs of remorse, and that he’d offered no final words. But, as years have passed, I’ve often wondered (who knows why) what Spencer had selected as his final meal. I’ve never found out, but here’s why I mentioned it.

Recently, a Cornell University study has concluded that a condemned person’s last meal selection can actually shed a little light as to his/her true guilt or innocence.

For example, researcher Kevin Kniffin, found that inmates who perceive themselves as innocent likely request a meal of fewer calories, or they decline to receive a last meal altogether (Kniffin’s study included the last meals of 247 people who were executed in the United States between 2002 and 2006).

Further, inmates who claimed innocence were 2.7 times more likely to decline a last meal than those who admitted guilt.

Interestingly, Kniffin’s research concluded that those who readily admitted guilty requested 34% more calories and were more likely to request brand name food items.

For example, those who denied guilt requested meals containing approximately 2,000 calories, and that’s if they chose to eat a final meal at all. Death row prisoners who admitted their guilt requested a last supper of approximately 2,800 calories. Those who remained silent, neither confessing guilt or sticking to a claim of “I didn’t do it,” asked for a meal of approximately 2,100 calories.

So, you be the judge. Guilty or Innocent?

1. John Wayne Gacy – 12 fried shrimp, a bucket of original recipe KFC, french fries, and a pound of strawberries.

2. Ted Bundy – steak (medium rare), eggs (over easy), hash browns, toast with butter and jelly, milk and juice.

3. Victor Feguer – a single unpitted olive presented on a ceramic plate and accompanied with a knife and fork.

4. Timothy McVeigh – two pints of mint and chocolate chip ice cream

*By the way, Patricia Cornwell’s first book was based on Spencer’s case.

 

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My Cousin Is An Asian-German-British Pygmy From Rome…Y’all

Asian, German, British

 

Last week I was just an average guy. I was born in an average size town situated in a small state where not much goes on, well, unless you count the state fair, fishing, and raising chickens. Lots and lots of chickens.

Things changed for me just a couple of days ago, when I learned that my lineage began in East Africa where the ancestors on my mother’s side, who were among the first people to leave their homeland, moved northward to follow good weather and plentiful game. The arduous trek took them along the banks of the Nile where water was plentiful, for a change. Their descendants eventually wound up in the Mediterranean region and western Asia, where they hung out with Neanderthals. Now, this was some 60,000 years ago, so “hanging out” merely meant to co-exist, not yuck it up together at the local cave bar while sipping on dinosaur dung daiquiris.

Along the same time, my father’s ancestors also journeyed out of Africa to the Middle East, India, and Europe. They were hunters and gatherers. Actually, a fair number of these folks, Mbuti and Biaka Pygmies, remained in Africa (I guess I now understand the short stature of many of my relatives).

My father’s peeps, some of the first to arrive in Asia, Southeast Asia, and Australia (they were the ancestors of the Aborigines) eventually made their way to the Americas.

Australian Outback

Sometime around 50,000 years ago (no, grandson, I know you think I’m old, but I was not alive back then), the males in my lineage gave rise to the genetic marker that is currently found in 90-95% of all non-Africans. This group had settled in the Middle East; however, the climate there grew colder, so, being nomadic, they moved on to bigger, better, and warmer places, traveling through what is now known as Iran, to Antolia (Turkey) and the Balkins. Our lineage is still found today in a small number of Pakistani’s.

Meanwhile, my mother’s ancestors, some now Cro-Magnon, had reached Europe. Their friends, the Neanderthals, had ceased to exist. My maternal ancestors’ lineage can still be found in people of Ethiopia, Somalia, and Arabia.

Near Endaselassie, Ethiopia

Still moving, many of my maternal ancestors settled into Western Europe, Asia, and southern portions of Russia. Some made their way back into Africa where they likely fell victim to the Arab slave trade.

So, with changing climate and the urge to travel (now I understand why Denene and I have moved so often over the years), a large number of my mother’s ancestors ended up in Rome and Athens. In fact, our particular marker is found in 40-60% of European populations.

So, as my mother’s people were finally establishing some roots in Europe, my paternal ancestors were still on the move. One specific marker in their genetic make up started in Central Asia, but moved on to Europe—the UK, Ireland, France, and Spain.

Part of my lineage can be found today in Russia, Northern Africa, the Balkins, Asia, and in approximately 55-58% of Western European lineages (43% of Central European lineages). Some made the journey to the Americas.

My male genes are strongly present in France, Ireland, and Spain. And our presence is known in Iraq, Lebanon, and Kazakhstan. I’m distantly related to Croatians, but more closely related to the Ashkenazi Jewish population.

Finally, my parents met, dated, and enjoyed spending time with each family, not really knowing a lot about either.

My mother’s grandmother was Native American (Cherokee), and I distinctly remember her long silky-black hair that remained dark even into her elder years. Her eyes were the color of burnt motor oil. She was a quiet and soft-spoken woman who loved to cook on the wood stove in her small kitchen. Everything was homemade, including the bread pudding and yeast rolls that I adored.

My great-grandmother was the only person in my immediate family of a different ethnic background, or so I thought. Never would I have expected to be related to Mbuti and Biaka Pygmies, or that my ancestors had been slaves. Sure, I knew that all man had originated in Africa, but I guess I never really thought about the journeys that took place during the thousands of years after my first genetic marker was born.

Having my DNA examined by the National Geographic Genegraphic Project certainly opened my eyes. The experiences took me on an adventure that began some 140,000 years ago, and will continue until men and women no longer exist. And, with all the troubles in the world today, the end of human existence may not be all that far away. I’m just saying…

 

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Test The DNA Knowledge Of Your Protagonist

An April Fools crime solving puzzle

 

Detectives Slim N. None and Frank Lee Iduncare caught the case of their careers when Captain I. Giterdun assigned them to investigate the murder of one of Savannah’s most popular ghost tour managers, I.C. Spooks.

The two top cops arrived on the scene and found Ms. Spooks’ body (her friends call her Ida, they’d learned) lying in a cobblestone alley just off River Street, near the entrance to the Gulp ‘Em Down Oyster Bar and Rot Gut Drink Emporium.

No witnesses and no obvious clues. No weapon and no sign of injury or open wounds. Not even so much as a chipped fingernail. No footprints on the stones. Not a single thing to go on. Well, except for a tiny dot of something reddish brown on the tip of the victim’s right index finger. None said the drop certainly looked like blood. To be certain, though, they’d have to wait for the autopsy report, hoping the M.E. would come up with the impossible. In the meantime, the detectives did what they do best…knocked on doors and asked a lot of questions. In other words, they pestered people until they either talked or slammed the door in the eager faces of the two detectives. The latter being the more common occurrence.

Turns out that it was DNA that solved the Spooks murder case. Below are the possible findings of Savannah medical examiner Y. N. Sizion. Nine of the things listed could be true scenarios. One, however, is not. Do you have what it takes to spot the April Fools finding? Well, let’s see if your protagonist really knows her DNA, or, if her knowledge was gained from watching Castle reruns.

The List

1. After developing a list of ten perfectly possible perpetrators, a positive match to suspect number ten was discovered by matching DNA from the crime scene to the DNA found in a recently-formed dental mold (the suspect was fitted for a new crown the day prior to the murder).

2. The suspect was identified by matching DNA found at the crime scene to DNA found on the mouth opening of a seriously shrunken ski mask located in a overflowing and lopsided clothes basket in the suspect’s apartment.

3. The medical examiner found a single foreign hair (no root) lodged deep in the throat of the victim. DNA found in the hair matched the DNA of one of the suspects.

4. The killer had forced oral copulation on the victim prior to her death. The victim’s DNA matched DNA swabbed from the suspect’s “private part” several hours after the offense.

5. DNA found on a cigarette butt lying near the victim’s body matched the DNA of one of the ten suspects. Faced with the DNA evidence linking him to the crime scene, he, suspect number seven, confessed to the murder.

6. Detective Iduncare found a crumpled postcard wedged between the north side trolley rail and a loose cobblestone. DNA found on the back of the card’s postage stamp was a positive match to suspect number four.

7. None and Iduncare were pleased and positively elated when the lab identified suspect number five by matching the DNA found at the crime scene to the DNA extracted from the suspect’s red blood cells.

8. A scientist from the lab called Iduncare to deliver the news he’d been waiting to hear…yes, the scientist had indeed discovered DNA on Spooks’ body, but what she’d found was a mixture, meaning there could have been more than one suspect. She went on to say that since her discovery was a mixture, she would not and could not positively include or exclude any one person as a suspect in the crime.

9. Detective None interviewed the Gulp ‘Em Down bartender and learned the poor woman had a nasty cold. She also said that, out of curiosity, she’d walked over to have a look at the body where she engaged in one of the worst coughing and sneezing fits of her entire 27 years on the planet. And, yes, she probably sprayed the corpse with quite a bit a spittle in the process. “That wasn’t a problem, was it?” the pink and green-haired woman asked while using a wadded bar napkin to mop the end of her dripping nose. Detective None learned from the folks at the lab that blowing cold remnants on a dead body could indeed compromise whatever DNA they found.

10. During the testing, scientists found the DNA of several people on the victim’s body, including that of None and Iduncare, who should have worn gloves while processing the crime scene.

After the lab results finally came back, and all was sorted through and pawed at by a team of prosecutors, None and Iduncare were finally able to slap the cuffs onto the wrists of their suspect(s).

And, future ghost tours were proud to boast of a brand new spirit, the recently departed I.C. Spooks, whose ghost could often be seen peering out at tourists from behind windows of various businesses and storefronts along the riverfront.

*Top photo – Savannah-Chatham Metro Police Department

* Bottom photo – I.C. (Ida) Spooks

 

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CODIS, SMODISH…Start Your Own DNA Database

Codis Smodish

 

We’ve all heard the stories of long turnaround time for DNA analysis, and the subsequent submission to CODIS for possible matches, especially in cases related to murder and rape investigations. But, when submitted evidence is for lower priority crimes—car break-ins and small scale drug use and sales, well, it’s safe to say the results are returned at an even slower pace. In some cases, the wait can be as long as 12 to 18 months.

CODIS (Combined DNA Index System), in conjunction with NDIS (National DNA Index System) is the world’s largest database record of offender DNA—10 million DNA profiles. Each of those profiles, merely a series of numbers—is representative of a single person. To match a suspect to one of those stored profiles is definitely not as quick and easy as TV leads us to believe.

First, investigators must collect a piece of evidence containing possible DNA—cigarette butt, bottle, drinking glass, bed sheet, condom, baggie (drug crime), etc. Next, the investigator delivers the packaged evidence to a laboratory where the actual DNA testing is performed (above photo). The laboratory then submits their results, a “forensic unknown,” to CODIS.

Ideally, there’s a local CODIS system in place, where the submitted profile is compared to the profiles of known, local offenders (remember, most crimes are committed by the same people, over and over again, especially in small jurisdictions). If no match is received there, then the profile would be sent to the state CODIS system. No match at the state level and the profile is next entered into the national database for comparison to the 10 million profiles stored there.

So, as you see, it can be a long process. And, in fact, many times the offenders have committed numerous other crimes before a “hit” comes back on the original profile, if at all.

So, some local police agencies are partnering with local private DNA testing companies, in lieu of the government-run NDIS/CODIS, hoping to greatly reduce turnaround times on their evidence. Of course, those private labs must be certified and accredited.

Departments using the private labs are enjoying extremely quick results, in as few as 30 days. And what that means to the police department is that they’re able to solve more crimes at a faster rate, putting the bad guys in jail before they commit a long string of unsolved crimes. And, those low-on-the-priority-list crimes are also solved at a quicker pace. For example, a baggie containing heroin residue is found at the scene of a crime. Unlike the standard month’s-long wait, a quick test on the DNA left on the bag could turn up a near-instant profile match in the local system.

A great example of the local lab/police department system is in Bensalem, Pa., where local police, in conjunction with a local lab, have established their own DNA database (LODIS) of approximately 4,000 samples/profiles. There, officers submit approximately 150 samples each month. Out of those samples, 80 crimes have been solved, as opposed to less than 10 hits from CODIS in the year or so before the Bensalem Township PD started their LODIS database. Turnaround time in the local LODIS system is a scant 30 days or less.

Bensalem is now enjoying a higher case clearance rate. An added bonus is that crime has actually decreased in the jurisdiction. Cases also move through the courts at a faster rate since criminals often take a plea deal when faced with DNA evidence against them.

Well, all this sounds too good to be true, right? Think again, because Rapid DNA testing is the next great law enforcement tool. You think 30 day test results are fast? Try DNA test results in 90 minutes!

Yep, bad guys beware, because with Rapid DNA the police could have your name in hand before the victim’s body arrives at the morgue.

 *Resource for Bensalem LODIS – Sheriff Magazine, Sep/Oct 2012

*Photos – Me

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