The nucleotide diversity across 1705 bp of the G6pd gene is studied in 50 Drosophila melanogaster and 12 D. simulans lines. Our earlier report contrasted intraspecific polymorphism and interspecific differences at silent and replacement sites in these species. This report expands the number of European and African lines and examines the pattern of polymorphism with respect to the common A/B all...

Considerable enzyme variation that is genetically controlled exists within and between natural populations of Drosophila. Our studies of two groups of sibling species show that allozyme differences can be used as species-diagnostic characters. A locus is defined as diagnostic if an individual can be correctly assigned to one of two species with a probability of 99% or higher. Between 15 and 32%...

Tuatara (two species of Sphenodon) are the last representatives of a branch of an ancient reptilian lineage, Sphenodontia, that have been isolated on the New Zealand landmass for 82 million years. We present analyses of geographic variation in allozymes, mitochondrial DNA, nuclear DNA sequences, and one-way albumin immunological comparisons. These all confirm a surprisingly low level of genetic...

Insights into processes that lead to the distribution of genetic variation within plant species require recognition of the importance of both pollen and seed movement. Here we investigate the contributions of pollen and seed movement to overall gene flow in the Central American epiphytic orchid, Laelia rubescens. Genetic diversity and structure were examined at multiple spatial scales in the tr...

Autopolyploid taxa present numerous challenges for population genetic analyses due to difficulties determining allele dosage. Dosage ambiguity hinders accurate assessment of allele frequencies, multilocus genotypes (MLGTs), as well as levels and patterns of clonality. The pervasiveness of polyploidy in the evolutionary history of plant taxa makes this a recurring problem. Whereas diploidization...

By combining 20 X chromosomes with five autosomal backgrounds, the relative importance of these factors with respect to the activity variations of G6PD and 6PGD in Drosophila melanogaster were investigated. Analysis of variance revealed that there exist significant X chromosome, autosomal background and genetic interaction effects. The effect of the X chromosome was due mainly to the two allozy...

The molecular evolution of mammalian Y-linked DNA sequences is of special interest because of their unique mode of inheritance: most Y-linked sequences are clonally inherited from father to son. Here we investigate the use of Y-linked sequences for phylogenetic inference. We describe a comparative analysis of a 515-bp region from the male sex-determining locus, Sry, in 22 murine rodents (subfam...

Previous tudies using phaseolin seed protein as a marker have revealed that cultivated common bean (Phaseolus vulgaris L.) resulted from multiple domestications in Mesoamerica and in Andean South America. Because these studies were based on variation at a single locus, confirmation was sought by analyzing patterns of diversity at nine polymorphic allozyme loci, all unlinked to the phaseolin loc...