Temporal stability of killifish hybrid clonal lineages

Abstract

The majority of vertebrates reproduce sexually, but a small percentage can reproduce clonally (asexual reproduction). The Common killifish (Fundulus heteroclitus) and Banded killifish (Fundulus diaphanus) are found along the Atlantic coast of Canada and sympatric populations are able to hybridize and produce female clones. These clonal lineages have independently arisen multiple times throughout the Maritimes, and Porter’s Lake, Nova Scotia, is the home of the best-studied population. Ten years earlier, ten clonal lineages were found, and one major clone was most prevalent in Porter’s Lake. As well, three out of 138 hybrids had genotypes consistent with sexual reproduction, and all clonal F1 hybrids had F. diaphanus mothers. The goals of my study were to: i) determine if the same major clone is still the most prevalent and if the same clonal lineages still persist at Porter’s Lake ten years later, ii) search for further sexually-reproducing hybrids, and iii) test if any hybrids have F. heteroclitus mothers. To do so, we used a species-specific mitochondrial DNA restriction fragment length polymorphism assay to assess maternal lineages and four nuclear microsatellite loci that have species-specific alleles to assign clonal lineages and test for sexually reproducing hybrids. Five new clonal lineages were detected as well as a new major clone, indicating that the clonal lineages are not temporally stable. Additionally, six potentially all-female sexual hybrids were identified out of the 51 hybrids found in 2018 and I found one F1 hybrid with a F. heteroclitus mother.