John C. Patton

An empirical evaluation of qualitative Hennigian analyses of protein electrophoretic data

SummaryIn an empirical evaluation of a qualitative approach to construction of phylogenetic trees from protein-electrophoretic data, we have employed Hennigian cladistic principles to generate molecular trees for waterfowl, rodents, bats, and other phylads. This procedure of tree construction is described in detail. Branching structures of molecular trees produced by three different algorithms were compared against those of “model” classifications previously proposed by other systematists. In each case, the qualitative cladistic trees provided fits to model phylogenies which were strong and as good or better than those resulting from phenetic-clustering or distance-Wagner trees based on manipulation of quantitative values in matrices of genetic distance.

Genetic Variability and Population Decline in Steller Sea Lions from the Gulf of Alaska

The western stock of the Steller sea lion (Eumetopias jubatus) was listed as endangered in 1997 due to its decline in numbers since the 1960s. We examined haplotypic diversity using nucleotide-sequence analysis of the control region of the mitochondrial DNA (mtDNA) from animals collected in 1976-1978 from the western and central Gulf of Alaska and compared results to previously published data from animals collected in the 1990s from the same geographic areas. No significant differences were found in frequencies of haplotypes between the two time periods, and genotypic diversity was high for all populations and time periods studied. It is concluded that, despite reduction in numbers, populations in the Gulf of Alaska have not lost appreciable genetic diversity, and if populations are allowed to recover, no long-term change in fitness is expected.

Evolutionary genetics of birds iv. rates of protein divergence in waterfowl anatidae

An electrophoretic comparison of proteins in 26 species of waterfowl (Anatidae), representing two major subfamilies and six subfamilial tribes, led to the following major conclusions: (1) the genetic data, analyzed phenetically and cladistically, generally support traditional concepts of evolutionary relationships, although some areas of disagreement are apparent; (2) species and genera within Anatidae exhibit smaller genetic distances at protein-coding loci than do most non-avian vertebrates of equivalent taxonomic rank; (3) the conservative pattern of protein differentiation in Anatidae parallels patterns previously reported in Passeriforme birds. If previous taxonomic assignments and ages of anatid fossils are reliable, it would appear that the conservative levels of protein divergence among living species may not be due to recent age of the family, but rather to a several-fold deceleration in rate of protein evolution relative to non-avian vertebrates.Since it now appears quite possible that homologous proteins can evolve at different rates in different phylads, molecular-based conclusions about absolute divergence times for species with a poor fossil record should remain appropriately reserved. However, the recognition and study of the phenomenon of apparent heterogeneity in rates of protein divergence across phylads may eventually enhance our understanding of molecular and organismal evolution.

Mitochondrial-DNA variation among subspecies and populations of sea otters (Enhydra lutris)

We used restriction-enzyme analysis of polymerase-chain reaction-amplified, mitochondrial DNA (mtDNA) to assess genetic differentiation of subspecies and populations of sea otters, Enhydra lutris , throughout the range of the species. There were several haplotypes of mtDNA in each subspecies and geographically separate populations. MtDNA sequence divergence of haplotypes of sea otters was 0.0004–0.0041 base substitutions per nucleotide. E. L nereis appears to have monophyletic mitochondrial DNA, while E. I. lutris and E. I. kenyoni do not. Different frequencies of haplotypes of mtDNA among populations reflect current restriction of gene flow and the unique histories of different populations. There are two or three haplotypes of mtDNA and diversity of haplotypes is 0.1376–0.5854 in each population of otters. This is consistent with theoretical work, which suggests that population bottlenecks of sea otters probably did not result in major losses of genetic variation for individual populations, or the species as a whole.

Salivary Amylase Variation in Peromyscus: Use in Species Identification

Genetic variation of salivary amylase was examined within and among populations of Peromyscus maniculatus and p. leucopus . Seven electromorphs were detected, four unique to P. maniculatus and two unique to p. leucopus . a seventh variant was restricted to p. leucopus within that species’ distribution but occurred in low frequency in p. maniculatus from east-central California. Thus, positive identification of these species where they occur sympatrically is possible using only amylase phenotypes. Electromorphs are distinct, easily separable, and under simple genetic control. Because of the ease of sample collection, lack of harm to the animal, and stability of the enzyme, this electrophoretic technique may find wide application in studies of the ecology, taxonomy, and distribution of these species.

Evolutionary genetics of birds. V. Genetic distances within Mimidae (mimic thrushes) and Vireonidae (vireos)

AbstractGenetic distances (Ds) between five species within each of the families Mimidae and Vireonidae were estimated from frequencies of protein electromorphs at 23 loci. For three mimid species in the genus Toxostoma,

Apparent Chromosomal Heterosis in a Fossorial Mammal

\bar D

Molecular systematic revision of tree bats (Lasiurini): doubling the native mammals of the Hawaiian Islands

equals 0.084 (range, 0.069–0.104); and among three mimid genera,