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Discordant introgression in a rapidly expanding hybrid swarm

Evolutionary Applications

By:
, , , , , and
DOI: 10.1111/j.1752-4571.2012.00249.x

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Abstract

The erosion of species boundaries can involve rapid evolutionary change. Consequently, many aspects of the process remain poorly understood, including the formation, expansion, and evolution of hybrid swarms. Biological invasions involving hybridization present exceptional opportunities to study the erosion of species boundaries because timelines of interactions and outcomes are frequently well known. Here, we examined clinal variation across codominant and maternally inherited genetic markers as well as phenotypic traits to characterize the expansion and evolution of a hybrid swarm between native Cyprinella venusta and invasive Cyprinella lutrensis minnows. Discordant introgression of phenotype, microsatellite multilocus genotype, and mtDNA haplotype indicates that the observable expansion of the C. venusta x C. lutrensis hybrid swarm is a false invasion front. Both parental and hybrid individuals closely resembling C. lutrensis are numerically dominant in the expansion wake, indicating that the non-native parental phenotype may be selectively favored. These findings show that cryptic introgression can extend beyond the phenotypic boundaries of hybrid swarms and that hybrid swarms likely expand more rapidly than can be documented from phenotypic variation alone. Similarly, dominance of a single parental phenotype following an introduction event may lead to instances of species erosion being mistaken for species displacement without hybridization.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Discordant introgression in a rapidly expanding hybrid swarm
Series title:
Evolutionary Applications
DOI:
10.1111/j.1752-4571.2012.00249.x
Volume
5
Issue:
4
Year Published:
2012
Language:
English
Publisher:
Blackwell Publishing, Ltd.
Publisher location:
Oxford, U.K.
Contributing office(s):
Fort Collins Science Center
Description:
13 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Evolutionary Applications
First page:
380
Last page:
392
Country:
United States