Sometimes, we just seem to get our tangs all tonguled up and use the wrong words in our stories. Perhaps we learned those incorrect little language units while watching television, or while reading a novel written by a die-hard CSI fan. Either way, here’s some words and facts about DNA that all writers should know if their stories involves this area of forensics.
ABI 310 Genetic Analyzer – capillary electrophoresis instrument used in laboratories for DNA testing.
ABI 310 Genetic Analyzer
Allele – an alternate form of a gene, such as hair color and the shape of your nose.
ASCLD – American Society of Crime Lab Directors.
Autoradiogram – a sort of x-ray picture of where radioactive probes have adhered to alleles. (It’s a picture of someone’s DNA).
Band – a picture of a DNA fragment.
Capillary Electrophoresis – a method of separating DNA using straw-like capillaries.
The scientist is pointing to the eight capillaries.
Chromosome – a very large piece of DNA.
23 pairs of chromsomes. Males have one Y and one X chromosome. Females have two X chromosomes.
CODIS – Combined DNA Index system. Established in 1998.
Degradation – chemical or physical breakdown of DNA.
Electrophoresis – method of separating DNA molecules using an electric field.
Electropherogram – A plotted printout of DNA test results.
Gel – medium used in electrophoresis to separate DNA.
Loading DNA into gel.
Genome – an organism’s genetic composition.
Locus – Location of a gene on a chromosome. (pl. Loci)
Mitochondrial DNA – DNA transferred only from mother to child.
STR – repetition of four tandomly repeated nucleotides. The FBI typically uses 13 STR loci in forensic analysis.
Identical twins have identical DNA.
Humans are genetically 99.9% identical. Only 0.1% of our genetic makeup is different.
It takes about eight hours for one cell to copy its own DNA.
Red blood cells do not contain DNA.
DNA is used to determine pedigree in livestock.
DNA is used to authenticate wine and caviar.
Detergent and Alcohol will not destroy DNA.
DNA can be transferred from article of clothing to another, even in a washing machine. This is called secondary and tertiary transfer.
DNA testing is not 100% accurate.
Criminal cases involving DNA evidence are usually quite serious in nature (homicide, rape, etc.). Less than 1% of that DNA evidence is reviewed by defense attorneys.
*I’m traveling this week and my internet access is quite limited. I hope you enjoy these reflections of past Graveyard Shift shift posts. I’ll check in when I can.