Newborns were examined for the presence of slow-moving haemoglobin components, tentatively designated X components and previously found in a group of Hb H disease in which invariably one of the parents of each patient had the same slow-moving Hb X components also. Structural studies showed that the abnormal haemoglobin in Chinese was identical with Hb Constant Spring, an c-chain variant. Newborns with Hb Bart’s and slow-moving X components invariably had one parent with the X components also. When the child grew older Hb Bart’s disappeared while the Hb X components remained in the blood. The homozygous state for the X components was found in a Malay boy through his newborn brother who had the X components in addition to Hb Bart’s and had both parents with the X components. One other Malay baby had the X components and Hb A2 Indonesia inherited from the parents. The present study of newborns also showed that Hb Bart’s can accompany different abnormalities of haemoglobin production, involving alpha-chains, beta-chains as well as gamm-chains. Its presence in cord blood is, therefore, not specific for alpha-thalassaemia
Key Words: Haemoglobinopathies; Hb Bart’s; Slow-moving Hb X; Thalassaemia
Blood samples, demographic and cultural data were collected from seven settlements of Semai Senoi, a swidden farming ethnic group of Malaysia. Three genetic loci (ABO blood group, hereditary ovalcytosis, and hemoglobin) were analyzed in a total sample of 546 individuals. These data indicate a considerable degree of genetic microdifferentiation in this area of the Semai distribution. Parent-offspring birthplace data (analyzed by means of a migration matrix) and settlement histories show that settlements are not strongly isolated. Genetic differences in the study area demonstrate a reasonable correspondence with migration and the history of the settlements. Genetic convergence also occurs through the addition of migrant groups to established populations leading to new patterns of marriage between donor and recipient groups. The genetic structure of the total Semai population through time thus comprises a mosaic of shifiting allele frequencies in a series of semi-isolated local populations.
1. A total of 8 samples from three natural populations and a laboratory strain of Aedes albopictus were analysed for glycerol-3-phosphate dehydrogenase phenotypes by means of horizontal starch-gel electrophoresis. 2. The electrophoretic phenotypes were governed by three codominant Gpd alleles. 3. There was low variability, with the heterozygosity in the variable samples ranging from 0.02 to 0.12. 4. The commonest allele in all the population samples was GpdB which encoded an electrophoretic band with intermediate mobility. 5. There was no temporal or spatial variation.
Glucose phosphate isomerase of subperiodic Brugia malayi was studied by horizontal starch-gel electrophoresis. Two heterophenotypes, each represented by 3 bands of enzyme activity, were found among 38 parasites studied. This finding is attributed to the occurrence of 2 Gpi gene loci.
Three genetic markers, red-cell UMPK, PGP and serum AMY2 were investigated in Malaysians of Malay, Chinese and Indian ancestries using starch-gel and agarose-gel electrophoresis. UMPK was found to be polymorphic in all three races. Variants were observed for PGP in Malays; in Indians it is a polymorphic marker whereas it is monomorphic in Chinese. AMY2 was polymorphic only in Indians. The UMPK1 frequencies in Malays, Chinese and Indians, respectively, are 0.851, 0.880 and 0.942. The PGP1 frequencies are 0.991, 1.000, 0.962, and the AMY1(2) frequencies are 1.000, 1.000 and 0.983.