Ch. 18 Flashcards
The Innocence Project
uses DNA retesting to free hundreds of wrongfully convicted prisoners w STRs (short tandem repeats), CNVs (copy number variants) and SNPs (single nucleotide polymorphisms)
Short Tandem Repeats (STRs)
short, repeated sequences, 2-9 bp in length; variation lies in # of repeats at each STR locus
Combined DNA Index System (CODIS)
FBI system to share DNA profiles
tracks 20 STRs for DNA profiling- generates 40 data points bc a person has 2 copies of each STR; started w 13 core loci + 7 more
includes genotype for a gene almelogenin to determine gender of DNA sample
Variable Number of Tandem Repeats (VNTRs)
repeats expanding & contracting in non-coding regions
cut DNA w/ restriction enzymes the separate DNA pieces using aragose gel electrophoresis
DNA Profiling by STR
Cell - DNA extraction - Mulitiplex PCR to amplify STR alleles - STR allele separation and sizing - Result interpretation- Database search against previous enrolled cell lines
A positive match between DNA profiles generated from evidence and suspects is determined by:
population frequency of the STR allelees present & pobability that two unrelated individuals would have the same DNA profile at these STR loci
Limitations of Forensic DNA Evidence
background dna, secondary transfer dna, cross-contamination
Haplogroups
group of similar haplotypes that share a common ancestor w/ a specific gene mutation
combo of alleles inherited together from one parent
Mitochondrial Haplogroups
at least 78 mitochondrial haplogroups are recognized. most ancient maternal (mtDNA) aplogroup, L, found mainly in Africa
Y Chromosome Haplogroups
Designated A-T; A is most ancient (Adam) in parallel to mitochrondrial Eve w/ many subhaplogroups
Ethnicity Estimates
depictgions of geographic origins derived efrom databases of individuals who know their family histories, documents, photographs, family stories of traditional genealogy
Genetic Genealogy
use of DNA testing in combo w/ traditional genealogical methods to trace family lineages, ancestral origins, and build family trees
AncestryDNA
associating SNP profiles w/ reported family origins to establish 26 reference populations (population has relatively distinctive genetic profile based on overall samples)
