Department of Genetics, North Carolina State University, Raleigh, North Carolina.
Department of Biology and Center for Genomics & Systems Biology, New York University, New York, New York.
Evolution. 2021 Jul;75(7):1607-1618. doi: 10.1111/evo.14244. Epub 2021 Jun 7.
The evolutionary potential of a population is shaped by the genetic architecture of its life-history traits. Early-life phenotypes are influenced by both maternal and offspring genotype, and efforts to understand life-history evolution therefore require consideration of the interactions between these separate but correlated genomes. We used a four-generation experimental pedigree to estimate the genetic architecture of early-life phenotypes in a species with dramatic variation in larval size and morphology. In the polychaete annelid Streblospio benedicti, females make either many small eggs that develop into complex larvae that feed in the plankton or few large eggs that develop into benthic juveniles without having to feed as larvae. By isolating the contributions of maternal, paternal, and zygotic genotype to larval traits, we determined that larval anatomical structures are governed by the offspring genotype at a small number of large-effect loci. Larval size is not shaped by the larva's own genotype but instead depends on loci that act in the mother, and at two genomic locations, by loci that act in the father. The overall phenotype of each larva thus depends on three separate genomes, and a population's response to selection on larval traits will reflect the interactions among them.
种群的进化潜力由其生活史特征的遗传结构塑造。早期表型既受母体和后代基因型的影响，因此，为了理解生活史进化，需要考虑这些独立但相关的基因组之间的相互作用。我们使用一个四代实验谱系，来估计在一种幼虫体型和形态变化很大的环节动物中，早期生活史表型的遗传结构。在多毛环节动物沙蚕属的一种物种中，雌性产生大量小卵，这些卵发育成在浮游生物中觅食的复杂幼虫，或者产生少量大卵，这些卵发育成不需要幼虫期觅食的底栖幼体。通过分离母体、父体和合子基因型对幼虫特征的贡献，我们确定幼虫的解剖结构由少数大效应基因座控制。幼虫的大小不受幼虫自身基因型的影响，而是取决于母体中的基因座，以及在两个基因组位置上，取决于父体中的基因座。因此，每个幼虫的整体表型取决于三个独立的基因组，而种群对幼虫特征的选择反应将反映它们之间的相互作用。
