ISSN:
0192-253X
Keywords:
marine molluscs
;
heterozygosity
;
growth
;
selection models
;
Life and Medical Sciences
;
Genetics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
We examine several models that may account for the observation that in populations of marine molluscs in general, and of the American oyster (Crassostrea virginica) in particular, the growth of an individual is related to its degree of heterozygosity and, also, that the number of heterozygous individuals in the population is less than expected on the assumption of random mating and no selection. We classify these models into nonselective, selective, and mixed models. We conclude that mixed models are the most likely to apply to real populations, but cannot exclude selective models. Nonselective models appear least likely. Current evidence favors a model that assumes that heterozygotes enjoy a fitness advantage as adults, primarily because of their faster growth, and that the lower numbers of heterozygotes in the population result from some form of nonrandom fertilization. One possible source of nonrandom fertilization is variation in the time of spawning of individuals due to differences in body size.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/dvg.1020040413