Biology 2581B Study Guide - Quiz Guide: Feature Selection, Stabilizing Selection, Balancing Selection
20 May 2020
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“Evolutionary biology looks at behaviour genetics” by Steven Gangestad
Abstract:
- Behaviour geneticists have demonstrated that most psychological individual differences owe
part of their variance to genetic variants
- Evolutionary biology offers a number of possible answers
- Arguments and current data which apply to variation in personality
1) Evolutionary biology looks at behaviour genetics
- Tom Bouchard: “Unravelling the role human individual differences play in evolution is the
next big hurdle and its solution will turn the behaviour genetics of human personality from
descriptive discipline to an explanatory one”
- In wide-ranging psychological domains – intellectual ability personality, psychopathology,
interests, values etc. find substantial genetic variation
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2) What explains genetic variation in personality?
- What evolutionary processes explain genetic variation?
2.1. What accounts for genetic variability in general?
- Fisher’s fundamental theorem states that the rate at which the mean fitness in a population
increases due to selection at a given time is equal to the genetic variance in fitness
- Selection decreases genetic variance → Exhausts additive genetic variation under ideal
conditions
- Five possibilities in which way genetic variation can arise?
1) No selection = unlikely
2) Mutations
-- Equilibrium = (mutation-selection balance) rate at which deleterious mutational effects
enter the population equals the rate at which they are removed
-- At equilibrium, many phenotypic traits are not directionally selected
-- Stabilizing selection would eventually eliminate variability around the intermediate
optimum
3) Variable selection = Selection itself may be variable
4) Negative frequency-dependent selection = rare variants tend to succeed in specific
situations
-- Social selection can also promote diversity in different personality types fit in different
social niches
5) Non-additivity = Genetic variance which is non-additive is not typically removed by
selection
-- Most non-additive forms of variance do not generate parent-offspring correlation and
selection on a parental generation does not change distribution of non-additive effects on
the offspring generation
- So what accounts for genetic variation in human personality?
- - Bouchard and Loehlin: Stabilising selection against extremes around optima, with some
variation within extremes possibly maintained by variable selection
Document Summary
Evolutionary biology looks at behaviour genetics by steven gangestad. Behaviour geneticists have demonstrated that most psychological individual differences owe part of their variance to genetic variants. Evolutionary biology offers a number of possible answers. Arguments and current data which apply to variation in personality: evolutionary biology looks at behaviour genetics. Tom bouchard: unravelling the role human individual differences play in evolution is the next big hurdle and its solution will turn the behaviour genetics of human personality from descriptive discipline to an explanatory one . Fisher"s fundamental theorem states that the rate at which the mean fitness in a population increases due to selection at a given time is equal to the genetic variance in fitness. Selection decreases genetic variance exhausts additive genetic variation under ideal conditions. Five possibilities in which way genetic variation can arise: no selection = unlikely, mutations.
