PubMed Health⌕ Search

Biomedical subjects

W J Diehl

Publications and source records attributed to W J Diehl.

6 recordsLinked to original sources
PubMed1999

Natural selection of the Pol gene of bovine immunodeficiency virus.

Genetic variability is a salient feature of lentiviruses, contributing to the pathogenesis of these viruses by enabling them to persist in the host and to resist anti-retroviral treatment. Bovine immunodeficiency virus (BIV), a lentivirus of unknown pathology, infects cattle in the United States and worldwide. Genetic diversity of BIV that is associated with naturally infected cattle is not well studied. We examined the genetic diversity and natural selection of a segment of the BIV pol gene amplified from the leukocyte DNA of naturally infected cattle. A portion of the reverse transcriptase domain (183 bp) of the pol region was targeted for amplification by PCR. PCR products were sequenced directly and aligned. When compared to the sequences of BIV R29-127, a molecular clone of the original BIV R29 isolate, all isolates were greater than 91% identical in nucleotide sequences and 77% identical in amino acid sequences. Pol genotypes were polymorphic at 14% of the nucleotide sites. The ratio of nonsynonymous to synonymous nucleotide substitutions (relative to the number of respective sites, Ka/Ks) was 0.16, indicating that this region of the BIV genome, like that of HIV-1, is subject to purifying selection. Based on the McDonald-Kreitman analysis, this region also was under positive Darwinian selection as HIV-1 and BIV diverged from a common progenitor. Phylogenetic analysis revealed that genotypes were geographically distinct, possibly indicating a common source of infection for animals within a herd.

Amino Acid Sequence↗
PubMed1990

Interrelationships of heterozygosity, growth rate and heterozygote deficiencies in the coot clam, Mulinia lateralis.

Allozyme surveys of marine invertebrates commonly report heterozygote deficiencies, a correlation between multiple locus heterozygosity and size, or both. Hypotheses advanced to account for these phenomena include inbreeding, null alleles, selection, spatial or temporal Wahlund effects, aneuploidy and molecular imprinting. Previous studies have been unable to clearly distinguish among these alternative hypotheses. This report analyzes a large data set (1906 individuals, 15 allozyme loci) from a single field collection of the coot clam Mulinia lateralis and demonstrates (1) significant heterozygote deficiencies at 13 of 15 loci, (2) a correlation between the magnitude of heterozygote deficiency at a locus and the effect of heterozygosity at that locus on shell length, and (3) a distribution of multilocus heterozygosity which deviates from that predicted by observed single-locus heterozygosities. A critical examination of the abovementioned hypotheses as sources of these findings rules out inbreeding, null alleles, aneuploidy, population mixing and imprinting as sole causes. The pooling of larval subpopulations subjected to varying degrees of selection, aneuploidy or imprinting could account for the patterns observed in this study.

Alleles↗
PubMed1989

The effect of glucose-6-phosphate isomerase genotype on in vitro specific activity and in vivo flux in Mytilus edulis.

Four samples of the mussel Mytilus edulis were taken between 1984 and 1987 from Stony Brook, New York, and used to study the glucose-6-phosphate isomerase (GPI) polymorphism in this species. In vitro specific activity and in vivo flux measured in the same animals were found to be significantly correlated. A significant effect of GPI genotype on flux was observed in one of the samples; overall, significant evidence of effect of genotype on enzyme activity was also obtained. GPI activities of common genotypes tend to deviate less from the population mean than those of rare (frequency less than 5%) genotypes. This suggests the possibility that rare GPI genotypes are rare as a consequence of having biochemical properties that deviate from an optimum level and, therefore, having a lower fitness. In support of this hypothesis, we found in one of our samples that shell length is a concave function of GPI activity with an intermediate optimum activity level.

Analysis of Variance↗
PubMed1988

The differential contribution by individual enzymes of glycolysis and protein catabolism to the relationship between heterozygosity and growth rate in the coot clam, Mulinia lateralis.

The locus-specific effects of heterozygosity upon individual growth rate were determined for 15 polymorphic enzymes among 1906 individuals from a single cohort sample of the marine bivalve Mulinia lateralis. Two measures of individual growth rate (total wet weight and shell length) were made at collection and after a period of growth in the laboratory. The correlation between heterozygosity and growth rate was independently determined for each locus using multiple linear regression, thereby providing a rank of individual locus effects; these differed significantly. The four estimated rankings of relative locus effects (initial length, initial weight, length added in the laboratory, and added weight) were not statistically different. That is, a locus with a large effect of heterozygosity on growth rate in nature had a similarly large effect on laboratory growth rate. The effect of a locus was not related to heterozygosity per se; some highly heterozygous loci had no detectable correlation with growth rate. The data contained two pairs of relatively tightly linked loci; in both cases one locus of a pair had significant effects on growth rate, while the other had no effect. Loci with large and significant correlations with growth rate synthesize enzymes which function in protein catabolism or glycolysis; heterozygosity in enzymes of the pentose shunt, redox balance, or other miscellaneous metabolic roles was not correlated with growth rate. Since the metabolic basis for the correlation is known to derive from individual differences in net energy status, particularly energetic costs of whole-body protein turnover, these data indicate that phenotypic effects (e.g., variation in growth rate) are determined by heterozygosity at the studied genes, not other linked loci.

Animals↗
PubMedDate not supplied

Distributions of polymorphisms among pathways of carbohydrate metabolism in the earthworm Eisenia fetida (Oligochaeta).

1. Activities and genetic banding patterns of 36 isozymes in carbohydrate metabolism were detected by spectrophotometry and starch-gel electrophoresis, respectively, in the earthworm Eisenia fetida. 2. Polymorphisms were not distributed randomly among metabolic pathways, activity levels, or gene copy numbers. 3. In glycolysis and the Krebs cycle, 16% of the loci were polymorphic and polymorphisms occurred only when multiple copies of the loci existed. 4. In other pathways, 45% of the loci were polymorphic and the distribution of polymorphisms was independent of gene copy number. 5. Polymorphisms may affect metabolic phenotypes and natural selection may have led to conserved biochemical activity in glycolysis and the Krebs cycle.

Animals↗