Biomedical subjects

J C Magalhães

Publications and source records attributed to J C Magalhães.

3 recordsLinked to original sources

PubMed2001

Suppes predicate for genetics and natural selection.

Patrick Suppes' slogan that "to axiomatize a theory is to present a set-theoretical predicate" was used in the synthetic theory of evolution. The system presented here extends the axiomatics of the evolutionary theory presented by M. Williams to encompass aspects of genetics. Some biological implications of the system are discussed, including the relationship between the Darwinian concept of fitness, as applied to organisms, and the concept of fitness as applied to genotypes, as it is normally used in population genetics. This paper should be viewed as an adjunct to the speculations on the logical-mathematical foundations of biological sciences.

Animals↗

PubMed1987

Study on a Brazilian isolate. I. Population structure and random genetic drift.

A number of parameters were evaluated in order to determine the level of isolation of a small Brazilian community existing in partial geographic isolation and thereby evaluate the random genetic drift potential in the population. On a theoretical basis, it is concluded that the probability of genetic drift is low but cannot be excluded. The relatively small proportion of migrants (26%), the limited individual mobility, as given by marital distance (29 +/- 7 km), the mean migrational distance (46 +/- 11 km), the small effective size (122), and the value of the product Neme (26) agree with the possibility of genetic drift in this population. The observed coefficient of inbreeding (0.00239) is lower than that expected (0.0066) for random mating, suggesting some pressures against consanguineous marriage.

Adolescent↗

PubMed1987

Study on a Brazilian isolate. II. Opportunity for selection.

The opportunity for selection, measured by prereproductive mortality and fertility, was calculated for a small and relatively isolated Brazilian population. The total index of selection opportunity (0.53) was low in comparison to those obtained for other isolated populations. The contribution of prereproductive mortality (Im = 0.28) was 40% higher than that of fertility (If = 0.20).

Brazil↗