Drift-Induced Selection Between Male and Female Heterogamety

Carl Veller, Pavitra Muralidhar, George W A Constable, Martin A. Nowak

Research output: Contribution to journalArticle

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Abstract

Evolutionary transitions between male and female heterogamety are common in both vertebrates and invertebrates. Theoretical studies of these transitions have found that, when all genotypes are equally fit, continuous paths of intermediate equilibria link the two sex chromosome systems. This observation has led to a belief that neutral evolution along these paths can drive transitions, and that arbitrarily small fitness differences among sex chromosome genotypes can determine the system to which evolution leads. Here, we study stochastic evolutionary dynamics along these equilibrium paths. We find non-neutrality, both in transitions retaining the ancestral pair of sex chromosomes, and in those creating a new pair. In fact, substitution rates are biased in favor of dominant sex determining chromosomes, which fix with higher probabilities than mutations of no effect. Using diffusion approximations, we show that this non-neutrality is a result of “drift-induced selection” operating at every point along the equilibrium paths: stochastic jumps off the paths return with, on average, a directional bias in favor of the dominant segregating sex chromosome. Our results offer a novel explanation for the observed preponderance of dominant sex determining genes, and hint that drift-induced selection may be a common force in standard population genetic systems.
LanguageEnglish
Pages711-727
Number of pages17
JournalGenetics
Volume207
Issue number2
Early online date4 Oct 2017
DOIs
StatusPublished - Oct 2017

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Sex Chromosomes
Genotype
Genetic Drift
Population Genetics
Invertebrates
Vertebrates
Theoretical Models
Mutation
Genes

Keywords

  • SEX DETERMINATION
  • HETEROGAMETY
  • GENETIC DRIFT
  • DRIFT-INDUCED SELECTION

Cite this

Drift-Induced Selection Between Male and Female Heterogamety. / Veller, Carl; Muralidhar, Pavitra; Constable, George W A; Nowak, Martin A.

In: Genetics, Vol. 207, No. 2, 10.2017, p. 711-727.

Research output: Contribution to journalArticle

Veller, C, Muralidhar, P, Constable, GWA & Nowak, MA 2017, 'Drift-Induced Selection Between Male and Female Heterogamety' Genetics, vol. 207, no. 2, pp. 711-727. DOI: 10.1534/genetics.117.300151
Veller C, Muralidhar P, Constable GWA, Nowak MA. Drift-Induced Selection Between Male and Female Heterogamety. Genetics. 2017 Oct;207(2):711-727. Available from, DOI: 10.1534/genetics.117.300151
Veller, Carl ; Muralidhar, Pavitra ; Constable, George W A ; Nowak, Martin A./ Drift-Induced Selection Between Male and Female Heterogamety. In: Genetics. 2017 ; Vol. 207, No. 2. pp. 711-727
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