Genomics and Health II

Question 1

Genome-wide association (GWAS)

Answer 1

SNP arrays (Microarrays) used to genotype individuals with and without the trait (generally ~100K - 1 million loci)

GWAS can also be done with whole-genome/whole-exome sequencing, usually short-read sequencing

Higher incidence of a SNP allele in individuals with the trait compared to those without the trait = association

Significance depends on degree of association and number of individuals tested – very low P value used for significance (P < 5 x 10-8) to avoid false +ves

Nearby (linked) candidate genes identified, tested

Question 2

The recombination event in meiosis is not entirely random

Question 3

SNPs near disease alleles often inherited together in haplotype blocks

Answer 3

d = disease susceptibility allele
m = marker SNP

marker is not necessarily the cause of the susceptibility