Abstract
Conditions for protected inversion polymorphism under the operation of both karyotype and supergene selection in a viability model have been analytically determined. When supergene selection (the effect of recombination in homokaryotypes lowering the mean fitness of their offspring) is acting on gene arrangements and there is no karyotype selection, it is demonstrated that a polymorphic stable equilibrium is reached by the population, which is a function of only the recombination effects in homokaryotypes. Under both supergene and karyotype selection the degree of dominance (h) of karyotype selection is critical to produce a protected inversion polymorphism. In general, the opportunity for protected polymorphism increases as the degree of dominance decreases. For small s values, the conditions for protected polymorphism are r > 2sh and c > 2s(h - 1), where r and c are the average loss of viability for offspring of ST/ST and IN/IN homokaryotypes, respectively. These findings suggest that supergene selection may be an important balancing mechanism contributing to the maintenance of inversion polymorphism.
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Selected References
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- Anderson W. W., Watanabe T. K. Selection by fertility in Drosophila pseudoobscura. Genetics. 1974 Jul;77(3):559–564. doi: 10.1093/genetics/77.3.559. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Charlesworth B., Charlesworth D. An experimental on recombination load in Drosophila melanogaster. Genet Res. 1975 Jun;25(3):267–274. doi: 10.1017/s001667230001569x. [DOI] [PubMed] [Google Scholar]
- Gromko M. H., Richmond R. C. Modes of Selection Maintaining an Inversion Polymorphism in DROSOPHILA PAULISTORUM. Genetics. 1978 Feb;88(2):357–366. doi: 10.1093/genetics/88.2.357. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kojima K. I., Tobari Y. N. Selective modes associated with karyotypes in Drosophila ananassae. II. Heterosis and frequency-dependent selection. Genetics. 1969 Nov;63(3):639–651. doi: 10.1093/genetics/63.3.639. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Prout T. The estimation of fitnesses from population data. Genetics. 1969 Dec;63(4):949–967. doi: 10.1093/genetics/63.4.949. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wasserman M. Factors influencing fitness in chromosomal strains in Drosophila subobscura. Genetics. 1972 Dec;72(4):691–708. doi: 10.1093/genetics/72.4.691. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wasserman M., Koepfer H. R. Fitness of karyotypes in Drosophila pseudoobscura. Genetics. 1975 Jan;79(1):113–126. doi: 10.1093/genetics/79.1.113. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wasserman M. Recombination-induced chromosomal heterosis. Genetics. 1968 Jan;58(1):125–139. doi: 10.1093/genetics/58.1.125. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Workman P. L. The analysis of simple genetic polymorphisms. Hum Biol. 1969 Feb;41(1):97–114. [PubMed] [Google Scholar]