Week 9 - Mapping Traits Flashcards
1
Q
What are genetic markers?
A
- short stretches of nucleotides
- known sequence
- known genomic location
- almost never causes disease
- no individual variability
- high population variability
- e.g. SNP, SNV, microsatellites
2
Q
What are SNPs?
A
- Single Nucleotide Polymorphism
- unique flanking sequence on each side
- occurs once in whole genome
- generally same between people
- indicated by rs number
- less common = minor allele
3
Q
What are microarrays?
A
- DNA from one person
- used for SNP analysis
- up to 2.5mil simultaneously
- find homozygous or heterozygous for each SNP
4
Q
What are microsatellites?
A
- repeat sequence of 2-4
- unique flanking sequence on each side
- repeat number constant within individual
5
Q
How are microsatellites detected?
A
- DNA isolated
- primers specific to the flanking sequence designed
- PCR amplification
- gel electrophoresis
- fragment length will determine repeat number
6
Q
What is homozygosity mapping?
A
- also called autozygosity
- mapping locus of AR trait
- consanguineous pedigree
- originate from common ancestor by non-random mating
7
Q
What is linkage mapping?
A
- identify locus of disease gene
- either AR or AD
- within families
- consanguinity not needed
- with SNPs or sequencing data
- considers if genetic loci are inherited together
8
Q
What is LOD?
A
- Logarithm Of Odds
- statistical measure of linkage
- compares likelihood of two loci being linked
- <-2 = no linkage
- > -2 and <3 = possible linkage
- > 3 = linkage
9
Q
What is a linkage map?
A
- LOD scores are plotted
- every genetic marker
- arranged by location
- creates a linkage peak
- disease gene likely to be between two markers creating the linkage peak
