Cytonuclear genetics of experimental fish hybrid zones inside Biosphere 2

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Two species of mosquitofish (family Poeciliidae) known to hybridize in nature were introduced into freshwater habitats inside Biosphere 2, and their population genetics were monitored after 2 years. Within four to six generations, nuclear and cytoplasmic markers characteristic of Gambusia holbrooki had risen greatly in frequency, although some Gambusia affinis alleles and haplotypes were retained primarily in recombinant genotypes, indicative of introgressive hybridization. The temporal cytonuclear dynamics proved similar to population genetic changes observed in replicated experimental hybrid populations outside of Biosphere 2, thus indicating strong directional selection favoring G. holbrooki genotypes across the range of environments monitored. When interpreted in the context of species-specific population demographies observed previously, results suggest that the extremely rapid evolution in these zones of secondary contact is attributable primarily to species differences in life-history traits.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Cytonuclear genetics of experimental fish hybrid zones inside Biosphere 2
Series title PNAS
Volume 91
Issue 11
Year Published 1994
Language English
Publisher National Academy of Sciences
Contributing office(s) Alaska Science Center
Description 4 p.
First page 5066
Last page 5069
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