ON THE EVOLUTION OF PARTHENOGENESIS. II. INBREEDING AND THE COST OF MEIOSIS

Area of Science:

• Evolutionary Genetics
• Reproductive Biology

Background:

• Inbreeding is hypothesized to resolve the paradox between successful biparental reproduction and the genetic benefits of uniparental reproduction.
• Understanding the role of inbreeding in the evolution of parthenogenesis is crucial for evolutionary biology.

Purpose of the Study:

• To analyze quantitative models of genetic change to determine the effect of inbreeding on parthenogenesis evolution.
• To investigate how inbreeding influences the cost of meiosis in different ploidy systems.

Main Methods:

• Analysis of quantitative genetic models.
• Examination of the effects of inbreeding on parent-offspring relatedness and female reproductive value.
• Comparison of inbreeding effects in diploids versus haplodiploids.

Main Results:

• Inbreeding has minimal impact on the cost of meiosis in diploids but increases it in haplodiploids.
• Inbreeding effects on meiosis costs are antagonistic: increased relatedness favors biparental reproduction, while higher female reproductive value favors parthenogenesis (thelytoky).
• In haplodiploids, the effect favoring thelytoky predominates, consistent with observations in species with high inbreeding.

Conclusions:

• Inbreeding directly promotes parthenogenesis in haplodiploids, independent of its effect on the sex ratio.
• The observed association between inbreeding and thelytoky in haplodiploid species supports the model's findings.
• Inbreeding's role in parthenogenesis evolution differs significantly between diploid and haplodiploid systems.