Biomedical subjects

M Stoneking

Publications and source records attributed to M Stoneking.

93 records · Page 6Linked to original sources

PubMed1979

Genetic variation, inheritance, and quaternary structure of malic enzyme in brook trout (Salvelinus fontinalis).

Electrophoretic variation is described for malic enzyme (ME) for the first time in brook trout (Salvelinus fontinalis). Since the quaternary structure of ME was not clear from examination of banding patterns in brook trout alone, ME phenotypes in rainbow trout (Salmo gairdneri)X brook trout hybrids as wel as in esocid species demonstrated that ME is tetrameric. A model of two duplicated loci is proposed to account for the observed variation. One locus (ME-2) is fixed and one locus (ME-1) is variable with three electrophoretically distinct alleles; the protein products of ME-1 are reduced in activity relative to the protein products of ME-2. Joint segregation was examined between ME-1, ME-2, and nine other biochemical loci in a splake--lake trout (Salvelinus namaycush) X brook trout hybrid--backcross. All pairwise examinations showed random assortment except ME-2 with an isocitrate dehydrogenase locus (IDH-3), which showed complete linkage in the splake backcross. This may be due to a chromosomal aberration.

Animals↗

PubMedDate not supplied

Mitochondrial DNA and human evolution.

Mitochondrial DNAs from 147 people, drawn from five geographic populations have been analysed by restriction mapping. All these mitochondrial DNAs stem from one woman who is postulated to have lived about 200,000 years ago, probably in Africa. All the populations examined except the African population have multiple origins, implying that each area was colonised repeatedly.

Biological Evolution↗

PubMedDate not supplied

Pseudolinkage of the duplicate loci for supernatant aspartate aminotransferase in brook trout, Salvelinus fontinalis.

Electrophoretic variation involving three alleles is described for the duplicated loci for supernatant aspartate aminotransferase (AAT-1,2), from muscle extracts of brook trout. Both loci exhibit largely disomic inheritance. Exceptional progeny types are proposed to be the result of a form of tetrasomic inheritance. Nonrandom segregation was found among the progeny of males doubly heterozygous for AAT markers; where so-called linkage phase was known, this nonrandom assortment was shown to be pseudolinkage (78.9 percent recombination). Analyses of joint segregation of triply heterozygous males for the AAT-(1,2) loci and for the single alpha glycerophosphate dehydrogenase locus (AGP-1) revealed true linkage of AGP-1 with one AAT locus (mean r = 11 percent), but pseudolinkage with the other AAT locus (r = 74 percent). Intraindividual variation for homoeologous multivalent pairing of two acrocentric with two metacentric chromosomes in males, but with bivalent pairing in females, is proposed to account for pseudolinkage and for the tetrasomically inherited types.

Animals↗