Genetic monitoring reveals two sympatric brown trout populations in a small mountain lake
(English)Manuscript (preprint) (Other academic)
It is contentious to what extent sympatric speciation represents a general and taxonomically widespread phenomenon. Documenting the occurrence of multiple, genetically distinct populations within areas lacking barriers to gene flow can increase our understanding of this type of speciation, because such populations are expected to represent the first steps of sympatric speciation. We analyzed the genetic relationships among over 4000 brown trout (Salmo trutta) collected during 19 sampling years from a series of small mountain lakes in northern Scandinavia. Our results clearly indicate the presence of two sympatric populations within these lakes. The populations are characterized by a high degree of genetic divergence coupled with a lack of apparent phenotypic dichotomy. The differentiation pattern appears stable over the two decades monitored, and the exchange of individuals between the two populations appears small. The existence of sympatric populations characterized by substantial genetic divergence may be a much more common phenomenon than anticipated, but difficult to detect in situations where morphological or ecological differentiation is missing. Larger samples than typically collected in a single sampling effort may be needed for revealing situations of sympatry, and for reliable estimation of the number of populations.
sympatric populations, heterozygote deficiency, salmonids, temporal genetics, cryptic populations
Research subject Population Genetics
IdentifiersURN: urn:nbn:se:su:diva-42940OAI: oai:DiVA.org:su-42940DiVA: diva2:352318