The spatial distribution of genotypes for nine polymorphic allozyme loci was examined in a contact zone between Pinus ponderosa var. scopulorum and another tree regarded as either a separate species, Pinus arizonica, or variety, Pinus ponderosa var. arizonica, in southern Arizona. Previous work had identified a steep elevational cline for a key taxonomic trait, number of leaf-needles per fascic...

Allozyme data are widely used to infer the phylogenies of populations and closely-related species. Numerous parsimony, distance, and likelihood methods have been proposed for phylogenetic analysis of these data; the relative merits of these methods have been debated vigorously, but their accuracy has not been well explored. In this study, I compare the performance of 13 phylogenetic methods (si...

Clinal variation is common for enzymes in the glycolytic pathway for Drosophila melanogaster and is generally accepted as an adaptive response to different climates. Although the enzyme phosphoglucomutase (PGM) possesses several allozyme polymorphisms, it is unique in that it had been reported to show no clinal variation. Our recent DNA sequence investigation of Pgm found extensive cryptic amin...

Twenty-nine populations of Xiphophorus fishes representing nine species of northern swordtails, one southern swordtail and a platyfish were assayed electrophoretically for allozyme variation. Phylogenetic relationships were inferred using parsimony and likeUhood analysis of gene frequency characters, as well as Fitch-Margoliash, minimum evolution and neighbor-joining analyses of genetic distanc...

Thehemlockwoolly adelgid,Adelges tsugaeAnnand(Hemiptera:Adelgidae), is amajor introduced pest of eastern hemlock, Tsuga canadensis (L.) Carrière. Hemlock woolly adelgid in the UnitedStates is anholocyclic andanobligateparthenogen, becauseno suitableprimaryhost (onwhich sexual reproduction occurs inAsia) is reported for this adelgid in theUnited States. Allozyme analyses were conducted to assess...

BY SURVEYING VARIATION AT ALLOZYME LOCI IN SEVERAL PHYTOPHAGOUS LEPIDOPTERAN SPECIES (GEOMETRIDAE), WE HAVE TESTED TWO HYPOTHESES ABOUT THE RELATIONSHIP OF GENETIC VARIATION TO ENVIRONMENTAL HETEROGENEITY: (1) that allozyme polymorphisms may exist because of associations between genotypes and "niches" (different host plants, in this instance), and (2) that the overall genetic variation of a spe...

Species are the units used to measure ecological diversity and alleles are the units of genetic diversity. Genetic variation within and among species has been documented most extensively using allozyme electrophoresis. This reveals wide differences in genetic variability within, and genetic distances among, species, demonstrating that species are not equivalent units of diversity. The extent to...

Advances in the taxonomy and ecological aspects concerning geographical distribution and hosts of the so far genetically recognised nine taxa of the nematodes belonging to genus Anisakis (i.e. A. pegreffii, A. simplex s.s., A. simplex C, A. typica, A. ziphidarum, Anisakis sp., A. physeteris, A. brevispiculata and A. paggiae) are here summarized. Genetic differentiation and phylogenetic relation...

Astragalus bibullatus (Fabaceae) is an endangered plant species endemic to limestone cedar glades in Tennessee. Data from 134 amplified fragment length polymorphism (AFLP) fragments indicate that populations of this species are genetically very similar, with genetic identity values ranging from 0.976 to 0.991. Approximately 10% of the species' total genetic variation is due to differences among...

An emerging problem of some interest is whether we can determine the population membership of a single individual, using a population-specific "genetic fingerprint." The levels of accuracy and precision required are beyond the reach of allozyme analysis, and attention has shifted to DNA polymorphisms. There are different types of DNA markers available for population surveys: RFLPs, mini- and mi...