Leonora Buentello

Blood groups and red cell acid phosphatase types in a Mixteca population resident in Mexico City.

Several blood groups, ABO, Rh, Ss, Fy, Jk, and red cell acid phosphatase (ACP) types were studied in a native Mixteca population that has resided in Mexico City since 1950. Gene frequencies were obtained and used to establish admixture estimates with blacks and whites. The subjects came from three different geographical areas: High Mixteca, Low Mixteca, and Coast Mixteca. All frequencies were in Hardy‐Weinberg equilibrium. The difference in the ABO frequencies was statistically significant when subjects from the three areas were compared simultaneously. Rh frequencies differed only between the High and the Low Mixteca populations. The ACP frequencies were similar between the Low Mixteca population and a previously reported Mestizo population. However, there were significant differences between the High Mixteca group and a Mestizo population, all the subjects being from Oaxaca. This is the first report of Ss, Fy, Jk, and ACP frequencies in a Mixteca population. Am. J. Hum. Biol. 11:525–529, 1999.

6-Phosphogluconate dehydrogenase (6-P-GD) in Down's syndrome

The question of whether the 6‐P‐GD system is located in chromosome 21 was approached in 2 ways: by measuring the erythrocyte 6‐P‐GD levels in children with Downs syndrome, and by studying the segregation of the electrophoretic variants of this enzyme in families with Downs syndrome individuals. Accepting that maternal meiotic non‐disjunction is the most frequent cause of the disease, there should be an excess of AB‐affected individuals born to AB mothers. The results do not support earlier suggestions that the 6‐P‐GD locus is located in chromosome 21.

Absence of correlation between Y chromosome heterochromatin and several anthropometric measurements in a Mexican population

SummaryThe correlation between nine anthropometric variables and six different measurements of the Y heterochromatic regions of 146 young Mexican adults was investigated. Only the absolute heterochromatic width showed a significant correlation at the 0.02 level with the upper segment/lower segment ratio, but the biological significance of this finding is strongly questioned.