PubMed Health⌕ Search

Biomedical subjects

Y M Parsons

Publications and source records attributed to Y M Parsons.

11 recordsLinked to original sources
PubMed2002

Mapping unexplored genomes: a genetic linkage map of the Hawaiian cricket Laupala.

As with many organisms of evolutionary interest, the Hawaiian cricket Laupala genome is not well characterized genetically. Mapping such an unexplored genome therefore presents challenges not often faced in model genetic organisms and not well covered in the literature. We discuss the evolutionary merits of Laupala as a model for speciation studies involving prezygotic change, our choice of marker system for detecting genetic variation, and the initial genetic expectations pertaining to the construction of any unknown genomic map in general and to the Laupala linkage map construction in particular. We used the technique of amplified fragment length polymorphism (AFLP) to develop a linkage map of Laupala. We utilized both EcoRI/MseI- and EcoRI/PstI-digested genomic DNA to generate AFLP bands and identified 309 markers that segregated among F(2) interspecific hybrid individuals. The map is composed of 231 markers distributed over 11 and 7 species-specific autosomal groups together with a number of putative X chromosome linkage groups. The integration of codominant markers enabled the identification of five homologous linkage groups corresponding to five of the seven autosomal chromosomal pairs found in Laupala.

Animals↗
PubMed2001

Species boundaries and genetic diversity among Hawaiian crickets of the genus Laupala identified using amplified fragment length polymorphism.

Crickets of the genus Laupala represent one of the many morphologically cryptic groups of insects, with the most closely related species distinguished only by the male calling song. Cryptic groups provide a challenge in determining the genetic boundaries between closely related populations and species. We have addressed the question of species boundaries in the Hawaiian cricket, Laupala, using nuclear DNA patterns sampled by the amplified fragment length polymorphism (AFLP) technique. This method has been used widely by plant researchers to facilitate the rapid assessment of genetic diversity in very closely related species and varieties. The AFLP technique is simple and robust, can be applied to any organism, and overcomes problems associated with cost, development time, information content and reproducibility that can plague other marker systems. Our results support previously hypothesized taxonomic relationships among sympatric populations and suggest close genetic relationships among allopatric, conspecific populations.

Animals↗
PubMed1996

Genetic variation in Australian Merino sheep.

Variation at 22 gene loci was investigated in a flock of Australian Merino sheep using restriction fragment length polymorphism (RFLP) analysis. Polymorphism was observed at 20 loci, including loci for wool keratin, hormone and immunoglobulin light chain genes. Eleven loci yielded unambiguous genotypes suitable for population data analysis. Average heterozygosity, determined from these and two monomorphic loci, was estimated as 0.107 (SE = 0.024). Average heterozygosity excluding all monomorphic data as estimated at 0.377 (SE = 0.031), which is comparable with human RFLP heterozygosities for loci chosen in the same way that we selected sheep loci.

Animals↗
PubMed1994

Linkage relationships between keratin-associated protein (KRTAP) genes and growth hormone in sheep.

The ovine hair keratin-associated protein (KRTAP) genes are grouped into several families. In this study, we analyzed linkage relationships between members of four KRTAP families and growth hormone and beta-hemoglobin. Restriction fragment length polymorphisms and a microsatellite polymorphism were typed in 10 sire groups from a flock of Australian Merino sheep. Two linkages, both previously undetected in sheep or any other mammal, were found. They were between growth hormone (GH) and the high-sulfur keratin gene family KRTAP1 (previously called high-sulfur B2C) at theta = 0.10, Z = 3.01 and between two high-glycine-tyrosine class genes, KRTAP6 (previously high-glycine-tyrosine type II) and KRTAP8 (previously high-glycine-tyrosine type I-F), at theta = 0.15, Z = 5.0. The high level of conservation of the mammalian genome at these recombination values suggests that these linkages might be found in distantly related mammalian species.

Animals↗
PubMed1994

Evidence of linkage between high-glycine-tyrosine keratin gene loci and wool fibre diameter in a Merino half-sib family.

Candidate genes for quantitative trait loci have been studied in a Medium Peppin Merino flock. Obvious candidates for effects on wool production traits are genes for the major proteins expressed in the wool fibre, the keratin and keratin-associated protein genes. Two keratin-associated protein loci, KRTAP6 and KRTAP8, have previously been shown to be linked. The results of analyses between these two loci and production traits gave significant evidence of linkage with wool fibre diameter in one out of eight half-sib groups tested. High-glycine-tyrosine proteins (KRTAP6, 7 and 8) are known to vary considerably in abundance in wool fibres and it is possible that a gene for major effect on fibre diameter is located within the same chromosomal region as KRTAP6 and KRTAP8.

Alleles↗