Search PubMed⌕ Search

Biomedical subjects

F B Livingstone

Publications and source records attributed to F B Livingstone.

16 recordsLinked to original sources
PubMed1992

Polymorphism and differential selection for the sexes.

Various genetic models with different fitnesses for the sexes are investigated. Only a limited set of fitness values will result in a stable polymorphism, and the rate of approach to these equilibrium frequencies is extremely slow. These results indicate that there are problems associated with the interpretation of some human genetic traits by such models.

Albinism↗
PubMed1992

Gene flow in the Pleistocene.

Previous estimates by Weiss and Maruyama (1976) and Rouhani (1989) of the time that an advantageous gene would take to disperse throughout hominid populations in the Pleistocene were considered to support the multiregional and single origin theories of the origin of modern humans, respectively. With the addition of some long-range gene flow, current simulations indicate that this dispersal could occur in 4000 generations, or in about 80,000 years. However, with a mutation rate of 10(-7) to mutants with the same selective advantage, such mutants would occur in populations before the 1 original mutant could disperse over this large area. The importance of gene flow in maintaining the species seems to be overemphasized.

Animals↗
PubMed1989

Simulation of the diffusion of the beta-globin variants in the Old World.

The distributions of the major hemoglobin variants found in the Old World are simulated assuming that each of the S, C, and E variants had a single origin and that beta-thalassemia occurred as many different mutations. The present distributions of these variants are considered unstable and were best approximated after about 100-150 generations of diffusion and selection. The model is considered to approximate the distributions of these variants better than hypotheses based on multiple mutations.

Africa, Western↗