[EHJ352H1] - Final Exam Guide - Everything you need to know! (43 pages long)
Document Summary
The genetic basis of phenotypic variation: the scale of the problem. Any two individuals are on average 99. 9% identical (still leaves 3. 2 million differences) The differences account for heritable phenotypic variation including disease susceptibility variation. Estimated 11 million common (>1%) snps plus many rare variants. Var(phenotype) = var(genetic factors) + var(environmental factors) If variation in the phenotype is at least partly due to genetic variation, there there is heritability for that trait. Heritability can be understood as the genetically determines proportion of trait variation in the population. The presence of heritability for the trait is a prerequisite for identifying genetic variants underlying trait variation. The effects at different loci add together to result in the phenotype. The more loci affecting the trait, the more genotypes there are with the same phenotype. As you get more and more genes involved, more genotypes start showing up.