Premium
BALANCING SELECTION IN A DESERT STREAM‐DWELLING FISH, POECILIOPSIS MONACHA
Author(s) -
Vrijenhoek Robert C.,
Pfeiler Edward,
Wetherington Jeffrey D.
Publication year - 1992
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.1992.tb01159.x
Subject(s) - biology , selection (genetic algorithm) , fish <actinopterygii> , desert (philosophy) , ecology , zoology , evolutionary biology , fishery , philosophy , epistemology , artificial intelligence , computer science
The desert stream‐dwelling fish Poeciliopsis monacha is exposed to extreme seasonal and spatial variation in physical stresses. We examined four diallelic gene loci ( Ldh‐1, Idh‐2, Pgd , and Ck‐A ) in P. monacha and tested whether genotypes were associated with differential survival of individuals exposed to acute stress. For each locus, the common allele was associated with higher survival during heat and hypoxic stress, whereas the alternate allele was associated with higher survival during cold stress. In most cases, survival of heterozygotes was intermediate and they exhibited less variance in survival than corresponding homozygotes. Identification of substantial linkage disequilibrium in these fish confounds our ability to discern whether the allozymes are the direct targets of selection, or if they just mark chromosomal regions that contain the true modifiers of survival. Nevertheless, the present results clearly identified balancing processes that can serve to stabilize genetic polymorphism in this species.