10 allozyme loci exhibit significant FsT values (Idh2 and
Ppl). The mean FST value for the 10 protein loci is
significant, but due entirely to the strong effect of the
Ppl locus. In contrast, 10 of the 11 independent cDNA
loci exhibit significant heterogeneity among popula-
tions and the mean FST value for the RFLPs is highly
significant. Although both sets of markers are character-
ized by having one highly variable locus, the most diver-
gent EWLP locus (GM798) exhibits allele frequencyvari-
ation among populations that exceeds the most
divergent allozyme locus (PPI) by a factor of 10.
Comparison of the mean FST values of the two types
of polymorphisms represents a modification of the Lew-
ontin-Krakauer (L-K) test for neutrality (LEWONTIN and
KRAKAUER 1973). As originally formulated, this test in-
volved comparing the allele frequency variation at one
set of loci (allozymes) to an expected theoretical vari-
ance. Application of the L-K test to spatial variation was
criticized on the basis that special patterns of migration
or mutation among subsets of the populations can lead
to inflated variance ratios (NEI and MARUYAMA 1975;
ROBERTSON 1975). By comparing allozyme and FWLP
loci in samples from similar geographic regions, how-
ever, one eliminates the confounding effects of un-
known population relationships. The L-K test statistic