Ecological-evolutionary relationships in Passiflora alata from Rio Grande do Sul, Brazil / Relações ecológico-evolutivas em Passiflora alata do Rio Grande do Sul, Brasil

The geographical distribution, ecological characteristics, flowering and fruiting times, and pollinating agents of Passiflora alata are considered and related to molecular genetic data gathered simultaneously. The first report on this species in Rio Grande do Sul was made in 1934, only in cultivated gardens. Approximately 20 years later, however, the species was already classified as efferata (wild) in Porto Alegre's suburbs. The data presented here, together with the DNA investigations, indicate that P. alata is actively colonizing previously unoccupied areas of this region.

A distribuição geográfica, as características ecológicas, as épocas de florescimento e frutificação, e os agentes polinizadores de Passiflora alata são considerados e relacionados a estudos genético-moleculares desenvolvidos simultaneamente. O primeiro registro da espécie no Rio Grande do Sul foi feito em 1934, apenas em área cultivada. Cerca de 20 anos depois, no entanto, a espécie já era classificada como efferata (selvagem) nos subúrbios de Porto Alegre. Os dados aqui apresentados, junto com as investigações de DNA, indicam que P. alata está colonizando ativamente áreas previamente não ocupadas desta região.

Frequency of CCR5delta32 in Brazilian populations

A sample of 103 randomly chosen healthy individuals from Alegrete, RS, Brazil, was tested for the CCR5delta32 allele, which is known to influence susceptibility to HIV-1 infection. The CCR5delta32 allele was identified by PCR amplification using specific primers flanking the region of deletion, followed by electrophoresis on a 3 percent agarose gel. The data obtained were compared to those reported for other populations and interpreted in terms of Brazilian history. The individuals studied came from a highly admixed population. Most of them were identified as white (N = 59), while blacks and browns (mulattoes) were N = 13 and N = 31, respectively. The observed frequencies, considering the white, black and brown samples (6.8, 3.8, and 6.4 percent, respectively), suggest an important European parental contribution, even in populations identified as black and brown. However, in Brazil as a whole, this allele shows gradients indicating a relatively good correlation with the classification based on skin color and other physical traits, used here to define major Brazilian population groups.

Evolutionary implications of infra- and interspecific molecular variability of pathogenesis-related proteins

We have examined phylogenetic relationships in seven pathogenesis-related (PR) protein families. Within-family comparisons involved 79 species, 166 amino acid sequences, and 1,791 sites. For 37 species, 124 different PR isoforms were identified (an average of 3.3 per species). Thirty-one of the 37 species investigated tended to cluster together (84 percent). Of the 17 clusters distinguished in the seven phylogenetic trees, 10 (59 percent) were in agreement with their taxonomic status, ascertained at the family level. The strong similarities among the intraspecific forms, as compared to interspecific differences, argue for some kind of gene conversion, but the rare occurrence of widely different isoforms also suggests diversifying selection. PRs 1, 6, and 4 seem to be less differentiated than PRs 3, 2, 10, and 5.

Genetics, surnames, grandparents' nationalities, and ethnic admixture in Southern Brazil: do the patterns of variation coincide?

A total of 2,708 individuals from the European-derived population of Rio Grande do Sul, divided into seven mesoregions, and of 226 individuals of similar origin from Santa Catarina were studied. Seventeen protein genetic systems, as well as grandparents' nationalities, individuals' surnames, and interethnic admixture were investigated. The alleles which presented the highest and lowest differences were GLO1*2 (16 per cent) and PGD*A (2 per cent), respectively, but in general no significant genetic differences were found among mesoregions. The values observed were generally those expected for individuals of European descent, with the largest difference being a lower prevalence (34-39per cent) of P*1. Significant heterogeneity among mesoregions was observed for the other variables considered, and was consistent with historical records. The Amerindian contribution to the gene pool of European-derived subjects in Rio Grande do Sul was estimated to be as high as 11 per cent. Based on the four data sets, the most general finding was a tendency for a northeast-southwest separation of the populations studied. Seven significant phenotype associations between systems were observed at the 5 per cent level (three at the 0.1 per cent level). Of the latter, the two most interesting (since they were also observed in other studies) were MNSs/Duffy and Rh/ACP.

Protein Genetics and Paternity Determinations in Southern Brazil.

A review is made of 961 cases of paternity determinations using a battery of 18 protein genetic systems. With this set, the a priori probability of exclusion is 89% but only 16% of the accused men were exonerated. Among the non-excluded, 55% had probabilities of 95% or more of being the father of the child considered. The results are in accordance with those from other centers which use equivalent sets of protein markers. When the direct study of DNA is not possible, these tests provide a relatively low-cost, reliable alternative for such determinations.

The relative importance of familial, reproductive and environmental factors in biliary atresia: etiological implications and effect on patient survival

The clinical records of 237 patients with extrahepatic biliary atresia (EHBA) attendi9ng King's College Hospital, London, between March 1973 and October 1985 were analyzed in terms of familial and reproductive factors, as well as of their possible effect on patient survival. The male: female ratio was 0.93, and the ages of the patients'mothers and fathers were significantly higher than would have been expected from sibship data. Similarly, the number of first-born children having EHBA was less than expected. In a subsample of 189 mothers, the obstetrical histories of women who had children with associated EHBA (20% of the total) showed: 1) a higher frequency of illness before and during pregnancy; 2) a higher level of pharmaceutical drug consumption during pregnancy, and 3) more fetal losses, especially in the gestation immediately preceding the patient's birth. Age at death (average 15.1 ñ 13.2 monthjs) and survival rates depend critically on surgical intervention and were not related to the presence or absence of extrahepatic malformations or to the type of atresia. The present observations, taken together with those of others, indicate that problems in the reproductive process or exposure to noxious environmental agents may be etiological factors in associated EHBA

Extrahepatic biliary atresia and twinning

Four pairs of discordant twins were observed in a series of 237 extrahepatic biliary atresia patients ascertained in London. The twinning prevalence (1.7%) was as expedcted considering the ethnic composition of the sample. Out of a total of 17 other twin pairs reported in the literature only one was concordant for the disease. Since only 17 instances of familial cases have been described, the conclusion is that any influence of genetic factors in this condition is likely to be manifested indirectly, possibly in the form of increased susceptibility of the biliary epithelium to infectious or toxic agents