Natural hybridization between individuals from genetically distinct populations or species, resulting in gene flow and subsequent introgression, plays a major role in evolution, together with natural selection and genetic drift. Hybridization may contribute to speciation as a potential source of adaptive novelty by the introgression of selectively favored alleles in the recipient population. In our study, we use single-nucleotide polymorphisms (SNPs) arrays to study and monitor genetic diversity as well as population structure in the comb jelly Mnemiopsis leidyi along the US Atlantic coast from Cape Cod to Chesapeake Bay. In particular, focusing on investigating patterns, directionality and evolution of hybridization. While all individuals north off Chesapeake Bay along the US east- coast were suggested to be non-admixed, the majority of individuals from Chesapeake Bay were of admixed origin. Hybridization was not restricted to F1 hybrids and first and second generation backcrosses were observed and hence introgression, which points to hybrids having an evolutionary advantage to thrive in the particular conditions of Chesapeake Bay. However, common garden experiments investigating the performance of hybrids under controlled conditions do not suggest a superior performance in terms of egg production, pointing to other mechanisms driving hybridization events in extreme events in nature.

Primary Presenter: Marti Pujolar, DTU (martipujolar@gmail.com)

Authors:

Cornelia Jaspers, DTU  (coja@aqua.dtu.dk)