This chapter was another that focused heavily on the schematics of genetics including; quantitative genetic, multivariate quantitative genetic, complex segregation, and quantitative trait locus linkage analyses all connecting back to the evolutionary models applying to these quantitative traits.
The big questions asked at the beginning of the chapter concerned human biologists and if they should be studying variation within the quantitative genetic framework?
What is mostly unknown is that a large portion of variation that is studied today is quantitative already. The example given here was anthropomorphicstudies and longevity studies and how their variability implies quantitative measure.
Below are relative ideas to keep in mind from the chapter:
- Heritability is represented by h^2. It is defined as the proportion of phenotypic variance due to additive genetic effects. H^2= Va/Va+Ve =Va/Vp
- When there is dominance at one or more loci the concept of heritability becomes more complicated. Pi= a1 + d1 + e1
- If you include variances due to both additive genetic and dominance it equals H^2= Va + Vd/ Va + Vd + Ve = Va +Vd/ Vp = Vg/Vp
- Regression analysis is often used to estimate narrow-sense heritability.
- Towne 1993
- He presented an interesting quantitative genetic analysis in that they made use of serial measurements on relatives. They modeled growth in infants within the first 2 years of life.
- Weiss 1993
- He compared narrow-sense heritability estimates for systolic blood pressure in different populations. Systolic blood pressure is a quantitative trait.
- Beall 1997
- He studied hypoxic ventilator response. It used the pedigree relationships to estimate the narrow-sense heritability’s.
- Jarvik 1998-
- Introduced a summary and description of complex segregation analysis with a welcome message, “I will describe the CSA methods with record brevity, facilitated by the absence of any equations.”
- Drift, Migration, and Population Structure Analysis From Quantitative Traits
- Drift and migration have the same effects on quantitative traits as they do on single locus genes