2 Changes in Quantitative Traits Over Time
quantitative traits
variation: standinging within a population or divergence between species
breed improvement
quantitative genetics:
population genetics, statistical theory, mathematicl modeling, genetics, and genomics
long-term laboratory, shorter-term selection, human biology, wild populations
mating system: inbred vs outbred, asexual species
haploids, diploids, and polyploids
2.1 A brief history of the study of the evolution of quantitative traits
2.1.1 the fusion of population and quantitative genetics
- biometricians vs Mendelians; rediscovery of Mendel in the early 1900s
- Fleeming Jenkin: “blending inheritance”, segregating variance
- Fisher 1918: expected resemblance between relatives; (additive-) genetic varaince components
- Sewall Wright and J. B. S. Haldane
- single-locus vs multiple-locus models of selection; Bulmer
- infinitesimal model
- Kimura: infinite-alleles model; diffusion approximations; neutral theory of molecular evolution
- Kingman: coalescent
2.1.2 the ongoing fusion of molecular and quantitative genetics
- the growing number of molecular-based markers; QTL mapping
- linkage analysis; association mapping
- missing heritability
- Hill-Robertson effect
2.1.3 The common thread between breeding and evolution in natural populations
- artificial selection (breeders) and nature evolution (evolutionary biologists)
- Jay Lush: breeder’s equation, \(R=h^2S\); genetic correlation
- Lande: multivariate extension of the breeder’s equation
- Alan Robertson: slection response as the covariance between the breeding value and relative fitness, \(R=\sigma(A_z,w)\)
- Fisher’s fundamental theorem of natural selection; Robertson’s secondary theorem
- Price: a general covariance-based expression
- Henderson: Best linear unbiased predictor (BLUP); Linear mixed model (LMM); Restricted maximum likelihood (REML)
- marker-assisted selection (MAS); a few well-chosen markers (Lande and Thompson); genomic selection (Meuwissen)