The basics of Forensic Genetics and DNA Flashcards
What is a gene?
Stretch of DNA coding for a certain characteristic.
What is an allele?
A variant of a gene.
Genotype means what?
Unique sequence of DNA - two inherited alleles.
Phenotype means what?
Detectable expressions of genes - hair colour, eye colour, etc.
What is a homozygote?
Two of the same co-dominant alleles.
What is a heterozygote?
Two different co-dominant alleles.
What is a polymorphism?
The exploitation of differences and mutations.
What are the polymorphisms used in forensics?
SNPs and STRs.
Satellite DNA means what?
Long repeats (hundreds and thousands of base pairs).
How many base pairs are in mini satellites?
8 to 100 base pairs.
How many base pairs are in micro satellites?
2 to 7 base pairs.
How many base pairs do we target in forensics?
2 to 7 base pairs (micro satellites).
Locus/loci means what?
Repeating area groups of co-dominant alleles.
What are some examples of forensic uses for DNA?
Determining origin, paternity testing, and DSV identification.
In what direction is DNA coded?
5 prime to 3 prime.
D8S1179 What does each point mean?
D - DNA
8 - the 8th chromosome
S - single copy
1179 - 1179th STR on chromosome 8
What are micro variants?
A full number of repeats but one allele has some random bases, this presents itself as a decimal.
Autosomal means what?
Non-sex chromosomes (22 pairs - 44 singles).
What purpose would we use Autosomal STRs?
To identify an indivdual.
What purpose would we use Autosomal STRs?
To identify an individual.
What purpose would we use Y STRs?
To identify male components, or a family grouping.
What purpose would we use X STRs?
To identify female components, or paternity.
What is a limitation of X STR?
It degrades quickly.
What are iSNPs used for?
Identification.
