(Very) Short Course, 1.10.2024
Genetics of Crossbreeding
Hans Sölkner, Negar Khayatzadeh
Background
Crossbreeding is very frequently practiced in livestock populations, either producing terminal crosses or forming composite breeds. Still, the genetic mechanisms causing hybrid effects (heterosis) are not well understood. This short course aims to provide some basic understanding of how to find levels of crossbreeding from genomic data and to estimate and map heterosis effects with data produced in crossbreeding experiments as well as from composite breeds.
Contents
Use of high throughput genomic data for predicting levels of crossbreeding/admixture
-> global admixture
-> local admixture
Heterosis: what it is and why it is important in livestock breeding
-> Concept of dominance and epistatic loss
-> Terminal crossbreds vs composite breeds
Estimation of heterosis effects (breed additive, dominance and epistatic)
-> Pedigree based approach: Effect coding done from types of crosses (Guinea pigs from Peru)
-> Genomic approach: effect coding from breed ancestry of SNP (Swiss Fleckvieh)
Mapping genes responsible for heterosis
-> Examples from maize and rice
-> Results from Swiss Fleckvieh
-> Data from advanced intercross lines of chicken