Testing the Viviparity‐Driven‐Conflict Hypothesis: Parent‐Offspring Conflict and the Evolution of Reproductive Isolation in a Poeciliid Fish

Abstract

The evolution of viviparity increases the potential for genomic conflicts between mothers and offspring over the level of maternal investment. The viviparity-driven-conflict hypothesis predicts that such conflicts will drive the evolution of asymmetrical reproductive isolation between populations with divergent mating systems. We tested this hypothesis using crosses between populations of a poeciliid fish that differ in their level of polyandry. Our results support the prediction of an asymmetry in the rate of spontaneous abortion in reciprocal crosses, with the highest rate occurring in crosses between females from a relatively monandrous population and males from a relatively polyandrous population. The patterns of offspring size were not consistent with the pattern predicted by the viviparity-driven-conflict hypothesis: crosses between a monandrous female and a polyandrous male did not produce larger offspring than the reciprocal cross. This discrepancy was due to the presence of an effect of the maternal population on offspring size: polyandrous females produced larger offspring than monandrous females. In addition, offspring size was positively correlated with maternal size in crosses involving a polyandrous male. We discuss these results in light of models for intra- and intergenomic epistasis and the rapid origin of asymmetric reproductive isolation in viviparous taxa.

Differences in offspring size predict the direction of isolation asymmetry between populations of a placental fish

“…In two previous studies, we observed isolation asymmetry in RHCs between populations of least killifish (Heterandria formosa) that display differences in size at birth [5,6]. In both of these studies, crosses between a female from a population characterized by small offspring (SO populations) and a male from a population characterized by large offspring (LO populations) had a higher rate of aborted embryos than the reciprocal hybrid cross.…”

With whom is the gene in conflict in offspring production?: Synthesis of the theories of intragenomic and parent-offspring conflict

“…These aborted seeds may potentially grow rapidly because micropylar peripheral and chalazal endosperms are the tissues, where resources are transferred from endosperm to embryo and from the mother tissues to an endosperm, respectively. In a viviparous fish, high rates of offspring abortion are observed but surviving offspring are large if females are from a relatively monandrous population (where females inhibit the demand of offspring weakly) are crossed with males from a relatively polyandrous population (where offspring demands resources strongly) than if those females are crossed with males from the same monandrous population (Schrader and Travis, 2008). This result also suggests that the cost of overgrowth exists.…”

“…The costs of overgrowth may exist in many organisms, including plants and animals (Carputo et al, 1999;Costa et al, 2004;Dawson, 1965;Haig and Westoby, 1991;Schrader and Travis, 2008;Scott et al, 1998;Vinkenoog et al, 2003). In plants, the balance of genomes in an endosperm is critical for normal seed maturation, and genomic imbalance often results in abortion of developing seeds (Carputo et al, 1999;Costa et al, 2004;Haig and Westoby, 1991;Scott et al, 1998;Vinkenoog et al, 2003).…”

“…One of the factors causing abortion is suggested to be overgrowth of offspring (Dawson, 1965;Schrader and Travis, 2008). Moreover in mice, the trade-off between size and number of offspring is influenced by paternal strains: the paternal strain producing small litters produces large pups (Hager and Johnstone, 2003).…”

The complete mitochondrial genome of the Monterrey platyfish ( Xiphophorus couchianus )

“…Poeciliids have been widely used for studying in fields ranging from ecology, evolution, genetics, and genomics to systematics. Species in the family Poeciliidae have been investigated in order to improve our understanding of the evolution of several life-history and behavioral traits (Kang et al, 2013;Schrader & Travis, 2008, 2009). Monterrey platyfish is also a small ornamental fish.…”