Genetic relationships among native americans based on beta-globin gene cluster haplotype frequencies

The distribution of b-globin gene haplotypes was studied in 209 Amerindians from eight tribes of the Brazilian Amazon: Asurini from Xingú, Awá-Guajá, Parakanã, Urubú-Kaapór, Zoé, Kayapó (Xikrin from the Bacajá village), Katuena, and Tiriyó. Nine different haplotypes were found, two of which (n. 11 and 13) had not been previously identified in Brazilian indigenous populations. Haplotype 2 (+ - - - -) was the most common in all groups studied, with frequencies varying from 70% to 100%, followed by haplotype 6 (- + + - +), with frequencies between 7% and 18%. The frequency distribution of the b-globin gene haplotypes in the eighteen Brazilian Amerindian populations studied to date is characterized by a reduced number of haplotypes (average of 3.5) and low levels of heterozygosity and intrapopulational differentiation, with a single clearly predominant haplotype in most tribes (haplotype 2). The Parakanã, Urubú-Kaapór, Tiriyó and Xavante tribes constitute exceptions, presenting at least four haplotypes with relatively high frequencies. The closest genetic relationships were observed between the Brazilian and the Colombian Amerindians (Wayuu, Kamsa and Inga), and, to a lesser extent, with the Huichol of Mexico. North-American Amerindians are more differentiated and clearly separated from all other tribes, except the Xavante, from Brazil, and the Mapuche, from Argentina. A restricted pool of ancestral haplotypes may explain the low diversity observed among most present-day Brazilian and Colombian Amerindian groups, while interethnic admixture could be the most important factor to explain the high number of haplotypes and high levels of diversity observed in some South-American and most North-American tribes.

Ambiente de moradia e controle primário em idosos

Este trabalho investigou a relação entre ambiente de moradia e duas modalidades de controle percebido controle primário (CP) e controle secundário (CS), referentes a esforços empreendidos para adaptar o ambiente às próprias necessidades e realizar metas (CP); adaptar-se ao ambiente (CS). Participaram 315 idosos (105 homens; 210 mulheres) residentes em Brasília-DF, entre 60 e 92 anos, selecionados de forma não-probabilística, por cotas de gênero. Os dados foram coletados no domicílio por meio de entrevista incluindo questões sócio-demográficas e uma escala de controle. Os resultados apontam: (1) Relação inversa entre CP e densidade social do ambiente de moradia - DESAM (r = -0,119; p ≤ 0,05); (2) Percepção de controle significativamente maior nos que dispunham de quarto exclusivo (t = 2,21; df = 313; p ≤ 0,05). Conclui-se que baixa DESAM facilita o CP nessa fase da vida em que muitas atividades são realizadas no domicílio, convertendo a liberdade de ação e a privacidade em necessidades importantes.