Comparisons among patterns exhibited by functionally distinct genetic markers have been widely used to infer the impacts of demography and selection in structuring genetic variation in natural populations. However, such multilocus comparisons remain an indirect evaluation of selection at particular candidate loci; ideally, the identification of a candidate gene by comparative genetic methodolog...

We present an analysis of Raphanus raphanistrum and simulations illustrating the utility of directly estimating male phenotypic selection gradients using genetic markers. The method offers a much more refined characterization of selection than attempting to assign paternity to individual progeny. Our analysis of R. raphanistrum reveals selection on remarkably fine features of floral morphology,...

Halictus ligatus Say and its cryptic sibling species H. poeyi Lepeletier were sampled from an area of sympatry and typed for mitochondrial DNA sequence differentiation, as was 1 individual of each species from allopatric populations. Two other species, H. rubicundus (Christ) and H. farinosus Smith, were included to root the tree. Phylogenetic analysis of the aligned sequences showed that H. lig...

Experimental perturbations of gene frequency at the esterase-5 locus in Drosophila pseudoobscura were carried out in a series of population cages started with differing numbers of founder chromosomes. Cages founded with few chromosomes showed changes in gene frequency at the allozyme locus. Such changes were less marked in cages founded with a larger sample of chromosomes. These experiments sho...

Allozyme analysis was used to assess genetic variability in tephritid fruit fly Bactrocera diversa and B. zonata. In our experimental conditions, allozyme analysis at twelve enzyme loci scores twenty one putative alleles. The amount of mean observed heterozygosity (HO) was 0.22 and 0.28 and amount of mean expected heterozygosity (HE) was 0.28 and 0.37, in B. diversa and B. zonata, respectively....

Genetic heterogeneity of samples of Euphausia krohnii and Nematoscelis megalops collected from a 6,000-km* area in western North Atlantic Slope Water was investigated by electrophoretic assay of allozymic variability at eight enzyme loci. Both species exhibited significant among-sample heterogeneity of allozyme frequencies. Genetic distances between samples were large for intraspecific comparis...

The population genetics of aquatic animals in the Florida Everglades may be strongly influenced by extinction and colonization dynamics. We combined analyses of allozyme and microsatellite loci to test the hypothesis that two levels of population structure are present for spotted sunfish (Pisces: Centrarchidae: Lepomis punctatus) inhabiting the Everglades. We hypothesized that annual cycles of ...

T HE controversial history of allozyme studies: Alternative heritable forms of enzymes, differing in charge or shape, have been known since the 1940s; these may be alleles of one gene (allozymes) or products of distinct but related genes (isozymes). LEWONTIN and HUBBY (1966), finding an unexpected bonanza of allozyme variation in Drosophila, re-cast the existing debate about the evolutionary me...