Population structure of blood groups in Central and South American Indians

The phenotype bioassay has been applied to samples of Indians from 12 countries of Central and South America. Using five blood group systems, more than 7,000 tested individuals were studied. The mean coefficient of kinship for pairs from the same place (a) is about 0.025, which is considerably higher than has been found for industrialized populations. The decline of kinship with distance (b) is moderate (0.003), indicating substantial migration. These results are similar to two other primitive populations.     

Tooth size of Ticuna Indians,Colombia, with phenetic comparisons to other Amerindian

This study reports on odontometric analyses of unadmixed, adult Ticuna Indians, Colombia, South America. This group is characterized by crown diameters intermediate in size relative to the known Amerindian range and, in turn, to the range in modern man. Sex dimorphism is absent in Ticuna tooth size; there is a strong retention of the M1 > M2 size sequence. The Ticuna are compared multivariately to other Indian groups reported in the literature, using the size and shape coefficients of L.S. Penrose. Tooth size clusters the groups into small, medium, and large-toothed classes, but does not yield a pattern attributable to known genetic or historical affinities. Shape coefficients distinguish Indians from non-Indians (Caucasian, Negroid, and Australian samples), primarily on the basis of I1–I2 proportionalities. Neither size nor shape discriminates between North and South American groups.     

Some Characteristics of Potyvirus Isolates from Vanilla tahitensis in French Polynesia and the Cook Islands

Further characterization of vanilla mosaic potyvirus (VaMV) confirmed that it is quite distinct from vanilla necrosis potyvirus (VNV). In immuno-blot ELISA, a polyclonal antiserum to vanilla mosaic virus from Vanilla tahitensis in French Polynesia did not react with vanilla necrosis potyvirus infected V. fragrans from Tonga. However, samples of V. tahitensis with leaf distortion and mosaic from the Cook Islands reacted strongly with the VaMV antiserum. Host range studies involving 20 plant species failed to find a host for VaMV outside the genus Vanilla, confirming that VaMV has a much more restricted host range than VNV. The mean particle length of V_aMV from purified preparations was 763 nm (Std. Dev. 48) and SDS-polyacrylamide electrophoresis indicates a single coat polypeptide of M_r 34 × lO³.     

Blood group, red cell enzyme and serum protein types in the Buka Islanders, Papua New Guinea

Genetic marker studies on a sample of 80 speakers of the Petats and Tinputs families of languages, all pupils at a single high school, indicate a homogeneity among them which can be extrapolated to their areas of origin. Buka and its offshore islands and the northern part of Bougainville Island in the North Solomons Province of Papua New Guinea. Several markers systems, most notably first-locus phosphoglucomutase and liver acetyltransferase, reinforce the morphological evidence that these peoples are quite distinct from most other Papua New Guinea populations, with whom, however, there has been some gene exchange, probably through East New Britain. Their principal affinities are with the peoples of the Solomon Islands to the south.     

Molecular modeling of glycosyltransferases involved in the biosynthesis of blood group A,blood group B,Forssman, and iGb3 antigens and their interaction with substrates

A terminal alpha1-3 linked Gal or GalNAc sugar residue is the common structure found in several oligosaccharide antigens, such as blood groups A and B, the xeno-antigen, the Forssman antigen, and the isogloboside 3 (iGb3) glycolipid. The enzymes involved in the addition of this residue display strong amino acid sequence similarities, suggesting a common fold. From a recently solved crystal structure of the bovine alpha3-galactosyltransferase complexed with UDP, homology modeling methods were used to build the four other enzymes of this family in their locked conformation. Nucleotide-sugars, the Mn2+ ion, and oligosaccharide acceptors were docked in the models. Nine different amino acid regions are involved in the substrate binding sites. After geometry optimization of the complexes and analysis of the predicted structures, the basis of the specificities can be rationalized. In the nucleotide-sugar binding site, the specificity between Gal or GalNAc transferase activity is due to the relative size of two clue amino acids. In the acceptor site, the presence of up to three tryptophan residues define the complexity of the oligosaccharide that can be specifically recognized. The modeling study helps in rationalizing the crystallographic data obtained in this family and provides insights on the basis of substrate and donor recognition.