Meeting Abstract
Sex is a conundrum: the practice is costly – performing mating displays, increased parasite or disease exposure, producing males who do not reproduce – but common. All-female asexual populations escape these costs and thus their population increases exponentially compared to their sexual counterparts. This advantage is often short-lived as the lack of recombination leads to the rapid accumulation of deleterious mutations and a hastened extinction through genomic decay – a phenomenon referred to as Muller’s rachet. Therefore, the primary theories as to the advantage of sexual reproduction stem from genetic recombination, which promotes genetic variation and facilitates new, beneficial phenotypic adaptations. However, these theories have long been countered by the fact that there are several asexual species who defy their mutation-predicted demise. This requires further investigation into the assumption that sexual species contain more phenotypic variation than asexual species. Gynogenetic asexual species – those who require sperm for stimulation of embryogenesis but do not integrate genetic information – provide a unique opportunity to study this question. Here we use the amazon molly, a gynogenetic fish originating from a hybridization event between a sailfin molly and Atlantic molly in Tampico, Mexico over 100,000 years ago. We used mirror image scrutiny to examine one aspect of variance in the cognitive phenotype of amazon and sailfin mollies. Other poeciliid fish show heritability of visual lateralization, implying a genetic component to this phenotype. No significant lateralization of eye use and no difference in overall variance occurred in sailfin and amazon mollies. This aspect of phenotypic variation is not predicted by the quantity of genetic variation in these species.
