Biomedical subjects

R H Gooding

Publications and source records attributed to R H Gooding.

At least 37 records · Page 2Linked to original sources

PubMed1994

Genetics of two colonies of Glossina pallidipes originating from allopatric populations in Kenya.

Two large colonies, originating from allopatric populations of Glossina pallidipes Austen, in the Shimba Hills and Nguruman, Kenya, which differ biologically and with respect to vectorial competence, were compared at fourteen enzyme loci using polyacrylamide gel electrophoresis. The colonies had similar levels of genetic diversity with approximately half of the loci being polymorphic, an average of 1.6-1.7 alleles per locus, and a mean heterozygosity per locus of approximately 18.4%. However, the colonies differed significantly in allele frequencies at the loci for phosphoglucomutase, glucose-6-phosphate dehydrogenase, xanthine oxidase, octanol dehydrogenase and phosphoglucose isomerase. The results were compared with earlier studies on this species and no evidence was found for selection of specific alleles during establishment or maintenance of colonies of G. pallidipes, nor were specific chromosomes, or marker genes, associated with the biological differences between the two colonies.

Alleles↗

PubMed1994

Genetic variability and segregation analysis in Glossina moristans moristans (Diptera: Glossinidae) using DNA fingerprinting.

DNA hybridization, using the M13 sequence as a probe, was used to analyze the genetic variability in four inbred lines of the tsetse fly Glossina morsitans morsitans Westwood. An average of 11.2 bands (ranging from 2 to 10 kb) were found per fly. An average of nine loci were detected in each line; 40% of the loci were polymorphic and the mean heterozygosity per locus varied from 0.098 to 0.29. Averaging the data across the four inbred lines, the band sharing estimates were 82.5% in males and 81.2% in females, and the mean band frequency estimates were 0.71 and 0.70 for males and females, respectively. Segregation of fragments, determined in "three generation" pedigrees, conformed to expected Mendelian ratios and two of seven fragments studied were linked to an X chromosome marker gene, ocra (body color).

Animals↗

PubMed1993

Genetic analysis by DNA fingerprinting in tsetse fly genomes.

Genomic DNA from tsetse flies (Diptera: Glossinidae: Glossina Wiedemann) was analyzed by hybridization using the whole M13 phage as a probe to reveal DNA fingerprinting (DNAfp) profiles. Intrapopulation variability, measured by comparison of DNAfp profiles of tsetse flies from a large colony of G. brevipalpis, showed a high degree of polymorphism similar to that found in other animal species. Different lines of G. m. morsitans, G. m. centralis, G. m. submorsitans, G. p. palpalis and G. p. gambiensis established from small colonies displayed less genetic variability than the G. brevipalpis population. The analysis of pedigree relationships within an inbred line of G. m. centralis conformed to a Mendelian inheritance pattern. In the pedigree presented no mutations were observed, one fragment was linked to the X chromosome, and three fragment sets were linked, but most fragments showed independent segregation. M13 revealed no characteristic DNAfp profile differences between the subgenus Glossina and the subgenus Nemorhina, but a conserved distribution pattern was found in the laboratory colonies within each subspecies. M13 also revealed line specific DNA fragments that may be useful as genetic markers to expand the present linkage map of G. m. morsitans.

Animals↗

PubMed1993

Genetic variation in a Tanzanian population of Glossina swynnertoni (Diptera: Glossinidae).

Adult Glossina swynnertoni Austen that emerged from puparia collected during 1989 and 1991 near Makuyuni, Tanzania, were examined by polyacrylamide gel electrophoresis. Fourteen of 17 enzymes were monomorphic. Midgut alkaline phosphatase (ALKPH), phosphoglucomutase (PGM), and glucose-6-phosphate isomerase (PGI) from the head and thorax were polymorphic. Banding patterns indicated that the locus for PGM was on the X chromosome and loci for ALKPH and PGI were autosomal. For the 17 loci studied, the mean heterozygosity per locus was 6.1 +/- 3.7% in the 1989 sample and 5.7 +/- 3.7% in the 1991 sample. The effective number of alleles per locus was 1.11 and 1.10 in these samples. This level of genetic variation was low compared with other populations of tsetse flies and indicated that the sample may have been drawn from a small inbred population or one that recently had gone through a genetic bottleneck.

Alleles↗

PubMed1993

Phylogenetically distant symbiotic microorganisms reside in Glossina midgut and ovary tissues.

Many blood-feeding insects, including tsetse flies (Diptera: Glossinidae), harbour intracellular bacterial symbionts. Using isolates from tissues of several Glossina species and diagnostic DNA oligonucleotide primers, a polymerase chain reaction (PCR) based assay was designed to identify symbiotic bacteria. Those inhabiting the midgut of Glossina were found to belong to the gamma subdivision, whereas ovarian Proteobacteria were of the alpha subdivision--probably genus Wolbachia (Rickettsiaceae). The presence of Wolbachia-like Rickettsia in the ovaries of G.morsitans subspecies may help to explain the maternally inherited incompatibility of some crosses within this species.

Animals↗

PubMed1992

Genetic variation in tsetse flies and implications for trypanosomiasis.

The role of tsetse flies in the transmission of trypanosomes has been known for nearly 100 years, their economic and public health impact justifying much of the research. About 20 years ago, no genetic variants of tsetses were known but the discovery of six visible mutants and the application o f protein electrophoretic techniques have changed the situation. During the intervening years many techniques have been developed to study the biology of the approximately 30 known species and subspecies of Glossina. Here, Ron Gooding summarizes recent developments in the estimation o f genetic variation in tsetse populations and speculates on the implications of this variation to population structure, vectorial capacity and disease control strategies.

Journal Article↗

PubMed1991

Genetic variation in Glossina brevipalpis, G.longipennis and G.pallidipes, and the phenetic relationships of Glossina species.

Glossina brevipalpis Newstead, G.longipennis Corti, and G.pallidipes Austen maintained at ILRAD, Nairobi, Kenya, were examined for genetic variation of fourteen enzyme loci, using polyacrylamide gel electrophoresis. G.brevipalpis had six polymorphic loci, an average of 1.46 effective alleles per locus and a mean heterozygosity per locus of 20.0 +/- 7.1%. The figures for the same parameters in G.longipennis were 3, 1.16 and 8.2 +/- 4.9%, and for G.pallidipes the figures were 7, 1.40 and 22.3 +/- 6.3%. Seven rare alleles were lost from the G.brevipalpis colony during a 1-year period, but no statistically significant changes were observed in the genetics of the colony during this period. Using allele frequency data for ten of the enzymes studied, and frequencies for these enzymes in other taxa, a phenogram was constructed that indicated that the subgenus Austenina (i.e. the fusca group) is the oldest of the three subgenera within the genus Glossina, and that the subgenus Glossina s.str. (i.e. the morsitans group) may be paraphyletic.

Alleles↗

PubMed1990

Genetic variation in two field populations and a laboratory colony of Glossina pallidipes (Diptera: Glossinidae).

Glossina pallidipes Austen from Lambwe and Nguruman in Kenya and a laboratory colony, originating from flies collected at Lambwe, were compared for 12 enzyme-gene systems using polyacrylamide gel electrophoresis. In the Nguruman, Lambwe, and colony flies, mean heterozygosities were 9.1, 15.3, and 16.5%, and polymorphism was observed in 3, 4, and 5 loci, respectively. Significant differences in number of gene products were observed between Nguruman and Lambwe flies at three loci, between Nguruman and colony flies at four loci, and between Lambwe and colony flies at two loci. Evidence is presented indicating that the locus for phosphoglucomutase is on the X chromosome, whereas loci for octanol dehydrogenase, malate dehydrogenase, phosphoglucose isomerase, and a thoracic esterase (Esterase-1) are autosomal.

Animals↗

PubMed1989

Genetics of two populations of Glossina morsitans centralis (Diptera: Glossinidae) from Zambia.

Glossina morsitans centralis Machado was collected from the main fly belt west of Mumbwa Zambia and from the apparently isolated 'Keembe pocket' and 11 gene-enzyme systems were examined by polyacrylamide gel electrophoresis. There were no significant differences in allele frequencies among flies collected entering a vehicle, from fly-rounds, or from F3 traps in the main fly belt. Mean heterozygosity per locus is slightly higher in flies from the main fly belt than it is in flies from the 'Keembe pocket'. Allele frequencies at loci for xanthine oxidase (Xo), aldehyde oxidase (Ao) and a thoracic esterase (Est-2) were significantly different in the two populations and it is concluded that there is little gene flow between them.

Alleles↗

PubMed1987

Tryptophan metabolism in tsetse flies and the consequences of its derangement.

Literature comparing salmon and wild type Glossina morsitans morsitans and that comparing tan and wild type Glossina palpalis palpalis is reviewed. New information is presented on behaviour and biochemistry of salmon and wild type G. m. morsitans. The eye color mutants result from two lesions in the tryptophan to xanthommatin pathway: lack of tryptophan oxygenase in G. m morsitans and failure to produce or retain xanthommatin in eyes (but not in testes) of G. p. palpalis. The salmon allele in G. m. morsitans is pleiotropic and profoundly affects many aspects of fly biology including longevity, reproductive capacity, vision, vectorial capacity and duration of flight, but not circadian rhythms. The tan allele in G. p. palpalis has little effect upon the biology of flies under laboratory conditions, except that tan flies appear less active than normal. Adult tsetse flies metabolize tryptophan to kynurenine which is excreted; fluctuations in activities of the enzymes producing kynurenine suggest this pathway is under metabolic control.

Animals↗

PubMed1985

Influence of the salmon mutant of Glossina morsitans morsitans on the susceptibility to infection with Trypanosoma congolense.

Four phenotypes of a sex-linked, maternally influenced semi-lethal eye color mutant of Glossina morsitans morsitans Westwood were fed on Trypanosoma congolense Broden infected guinea pigs. Infection rates were evaluated 25 days later by means of dissection. Procyclic as well as mature infections were significantly more common among females with salmon-colored eyes (sal/sal) than among heterozygous (+/sal, phenotypically wild-type) females. A tendency was found for more mature infections among sal/Y males than among wild-type males. Similarly, females tended to be more infected than males with both procyclic and mature infections. These results indicate that the genotype of the fly, exemplified by the allele salmon, might influence the development of T. congolense in G.m. morsitans. A possible explanation for this phenomenon is discussed.

Animals↗

PubMed1984

Genetics of Glossina morsitans morsitans (Diptera: Glossinidae). X. A mutant (sabr) having long scutellar apical bristles in females.

A line of Glossina morsitans morsitans Westwood was established in which females have scutellar apical bristles approximately three times as long as normal. In other respects the flies appear normal. The mutant allele, sabr, is recessive to the wild-type allele. The locus for sabr is located in linkage group III, 50 or more map units from the locus for malic dehydrogenase. Scutellar apical bristles in mutant flies are longer in flies emerging from puparia maintained at 30 degrees C than in flies emerging from puparia maintained at 25 degrees C.

Animals↗

PubMed1983

Genetics of Glossina morsitans morsitans (Diptera: Glossinidae). VII. Location of G6pd in linkage group I, and Alkph in linkage group II.

In Glossina morsitans morsitans Westwood the locus for glucose-6-phosphate dehydrogenase, G6pd, was found to be in linkage group I, approximately 35 to 42 map units to the left of ocra, the locus for body color. The locus for midgut alkaline phosphatase, Alkph, was found to be in linkage group II, within 0.41 map units of the locus for xanthine oxidase, Xo. The distance from Xo to the locus for aldehyde oxidase, Ao, was confirmed to be about 42 map units. No evidence for genetical recombination was found in male G. m. morsitans.

Alcohol Oxidoreductases↗

PubMed1981

Genetic polymorphism in three species of tsetse flies (Diptera: Glossinidae) in Upper Volta.

Natural populations of Glossina morsitans submorsitans Newstead, Glossina palpalis gambiensis Vanderplank and Glossina tachinoides Westwood occurring within 150 km of Bobo-Dioulasso, Upper Volta were examined using polyacrylamide gel electrophoresis. No variation was found in the banding pattern for arginine phosphokinase (EC 2.7.3.3). G. p. gambiensis and G. tachinoides had three alleles for each of the thoracic enzymes octanol dehydrogenase (EC 1.1.1.73), malic dehydrogenase (EC 1.1.1.37) and alpha-glycerophosphate dehydrogenase (EC 1.1.1.8) and for midgut alkaline phosphatase (EC 3.1.3.1). The same situation was found with G. m. submorsitans except that only two alleles for alpha-glycerophosphate dehydrogenase and one for alkaline phosphatase were found. In each species, and for each of the enzymes, one allele was present at a frequency of 95% or greater. There was little or no variation between populations. Two laboratory colonies of G. p. gambiensis had less genetic variation than wild populations.

Alcohol Oxidoreductases↗

PubMed1979