The utility of hypervariable DNA polymorphisms as a
general population genetics method was studied in three fish
species by the use of multilocus DNA fingerprinting.
Laboratory lines and field caught specimens from Belize and
Florida of the clonal species Rivulus marmoratus were examined
to determine the relative contributions of mutation and
migration to genetic variation in the species. Specimens of
Poecilia latipinna, the sailfin molly, from Florida and
Georgia were used to explore the properties of hypervariable
markers in the context of an outbred and abundant species that
exhibits typical levels of genetic variability at nuclear
loci. The results were compared to those of a previous
allozyme survey of the same populations. Samples of Morone saxatilis from the Chesapeake Bay system were used to
investigate the utility of hypervariable markers in the
description of genetic variation of an outbred species
depauperate in other measures of genetic variation.
The results of this study indicate that variation
observed among among R. marmoratus clones characterized by
hypervariable loci may be the result of natural selection;
based on the analyses of mutation rates and population
structure. Results from the work with P.latipinna showed
that hypervariable loci could have general utility as a method
for studying population structure. This utility was
demonstrated in the examination of Chesapeake Bay populations
of M. saxatilis. Large degrees of interindividual variation
at hypervariable loci permitted the characterization of
population structure within Chesapeake Bay populations of this species.
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