Drosophila mercatorum is a species that can give rise to totally homozygous parthenogenetic strains. Using the technique of DNA-DNA hybridization, we have assessed the overall single-copy DNA differences among three independently derived strains that represent three independent genomes. Among strains, the average difference between homoduplex and heteroduplex median melting temperatures is 1.3 ...

The classic evolutionary hypothesis of ecological opportunity proposes that both heterogeneity of resources and freedom from enemies promote phenotypic divergence as a response to increased niche availability. Although phenotypic divergence and speciation have often been inferred to be the primary consequences of the release from competition or predation that accompanies a shift to a new adapti...

Numerous studies have asked whether communities with many species deter invasions more so than do species-poor communities or whether dominant species deter invasion by colonizing species. However, little is known about whether high intraspecific diversity can deter biological invasions or whether particular genotypes might deter invasions. In this study, we present experimental evidence that i...

This paper re-evaluated the use of DNA barcodes in earthworm species identification by re-analyzing sequence data for the mitochondrial cytochrome c oxidase subunit 1 (COI) gene. This analysis unveiled and confirmed taxonomic inconsistencies which significantly affect data interpretation. When considering synonymy and misidentification in published records, our results revealed no shared COI ha...

Imprinted gene expression occurs during seed development in plants and is associated with differential DNA methylation of parental alleles, particularly at proximal transposable elements (TEs). Imprinting variability could contribute to observed parent-of-origin effects on seed development. We investigated intraspecific variation in imprinting, coupled with analysis of DNA methylation and small...

Intraspecific morphological variation in fish is typically associated with sexual dimorphism, or one of three common environmental gradients: variation in intensity of predation, variation in water velocity, or variation in feeding niche. The preponderance of examples of environment-associated morphological variation within fish species has been documented in freshwater systems. It is not clear...

Theories to explain the diversity of species have required that individual species occupy unique niches and/or vary in their response to environmental factors. Positive interactions within a species, although common in communities, have not been thought to maintain species diversity because in non-spatial models the more abundant species always outcompetes the rarer species. Here, we show, usin...

The discovery and characterization of informative intraspecific genetic markers is fundamental for evolutionary and conservation genetics studies. Here, we used nuclear ribosomal ITS sequences to access intraspecific genetic diversity in 23 species of the genus Passiflora L. Some degree of variation was detected in 21 of these. The Passiflora and Decaloba (DC.) Rchb. subgenera showed significan...

Divergence in mate recognition systems can lead to reproductive isolation. In this study, we investigate patterns of intraspecific variation that contribute to premating isolation within and between two haplodiploid species, Nasonia vitripennis and N. longicornis. In a broad-scale survey of 17 North American isofemale lines encompassing the two species, we report strong asymmetric sexual isolat...

Empirical data sets of intraspecific restriction site polymorphism in Drosophila have been gathered in order to test hypotheses derived from coalescent theory. Three main ideas are tested: (1) haplotype frequency in the sample contains information on the topological position of a given haplotype in a cladogram, (2) the frequency of a haplotype is related to the number of mutational connections ...