Genetica

, Volume 112, Issue 1, pp 515–534

Adaptive divergence and the evolution of reproductive isolation in the wild: an empirical demonstration using introduced sockeye salmon

  • Andrew P. Hendry
Article

DOI: 10.1023/A:1013367100865

Cite this article as:
Hendry, A.P. Genetica (2001) 112: 515. doi:10.1023/A:1013367100865

Abstract

Populations exposed to different ecological environments should diverge for phenotypic traits that influence survival and reproduction. This adaptive divergence should reduce gene flow between populations because immigrants become less fit than residents and because hybrids perform poorly in either environment (i.e., ecologically-dependent reproductive isolation). Here I demonstrate adaptive divergence and the evolution of reproductive isolation in populations of sockeye salmon (Oncorhynchus nerka) introduced from a common ancestral source into a new lake system (Lake Washington, Washington). The introduced fish founded several new populations, two of which experience very different environments during breeding and early development (Cedar River v.s. Pleasure Point beach). Over 13 generations, the two populations diverged for adult traits (female body size, male body depth; measured in the wild) and embryo traits (survival to hatching, development rate, size at emergence; measured in a common environment). The rates of divergence for these characters were similar to those observed in other examples of ‘rapid evolution’, and can best be attributed to natural selection. Partial reproductive isolation has evolved in concert with adaptive divergence: the rate of exchange of adults between the populations (determined using natural tags) is higher than the rate of gene flow (determined using DNA microsatellites). The demonstration that adaptive divergence can initiate reproductive isolation in less than 13 generations suggests that the first signs of ‘ecological speciation’ may appear soon after new environments are first colonized.

adaptation adaptive divergence adaptive radiation ecological speciation evolutionary rate microevolution natural selection reproductive isolation sockeye salmon 

Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • Andrew P. Hendry
    • 1
  1. 1.Organismic and Evolutionary Biology ProgramUniversity of MassachusettsAmherstUSA

Personalised recommendations