Investigação da fertilidade diferencial das heterozigotas como um eventual mecanismo homeostatico de manutenção do polimorfismo da hemoglobina S e da talassemia beta

AUTOR(ES)

Michelle Marcondes Mazzi

DATA DE PUBLICAÇÃO

2002

RESUMO

Homeostatic mechanisms that maintain hemoglobin S and beta thalasemia are not completely clear so far, being considered the presence of mechanisms either complimentary or alternative concerning the hypothesis of favorable selection of heterozygous by malaria. Increased fertility of heterozygous women is one of the suggested processes, though it has only been tested so far in indirect surveys and/or ones that have been carried out in areas with endemic malaria, which makes it difficult to split apart the influence of this disease over the reproductive behavior of heterozygous women. In the present work, the fertility of sickle-cell trait women (heterozygous AS) and thalasemic trait (heterozygous AT) was directly compared to the fertility of their sisters carrying normal hemoglobin (homozygous AA). The samples were obtained in a non-endemic malaria area (Araras, SP). It has been studied 53 AS women and their 43 AA sisters, both either married or sharing a stable relationship with their husband AA, as well as 68 AT women and their 45 AA sisters, also married with normal hemoglobin husbands. The average number of children per heterozygous AS and AT women (3.0755 and 2.7647 respectively) did not differ significantly from those observed among their control sisters (3.0000 and 2.3778 respectively). In addition, it was not observed a significant difference between the proportion of married women without children between the heterozygous women and their control sisters. The results herein presented hence does not support the hypothesis of increased fertility of heterozygous women as being a homeostatic mechanism able to maintain the polymorphism of either hemoglobin S and beta thalasemia

ASSUNTO(S)

polimorfismo (genetica) reprodução humana genetica de populações hemoglobinopatia

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