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K K Bhatia

Publications and source records attributed to K K Bhatia.

30 records · Page 2Linked to original sources
PubMed1985

Extremely high frequencies of alpha-globin gene deletion in Madang and on Kar Kar Island, Papua New Guinea.

Extremely high frequencies of the deletion form of alpha(+)-thalassemia (-alpha/), as studied by the DNA mapping technique, were found in the population of Madang, a coastal province in the north of Papua New Guinea (PNG) and in the population of Kar Kar, an island situated near Madang. Ninety-seven percent of the population tested from Madang and 89% of that from Kar Kar Island were either alpha(+)-thalassemia heterozygotes or homozygotes. By contrast, no examples of the deletion form were detected in the Eastern Highlands of PNG. The haplotype frequencies of alpha(+)-thalassemia (-alpha/) in Madang and Kar Kar Island were found to be 81.33% and 66.67%, respectively. A more detailed analysis of the gene deletion revealed that in both populations 96% were of the 4.2 kilobase (kb) type and 4% were of the 3.7-kb type. Thus, this group is the only example in which the 4.2-kb deletion is predominant over 3.7-kb defect. The presence in high frequencies of alpha(+)-thalassemia in the coastal area of Madang and on the neighboring island, where malaria has long been holoendemic or hyperendemic, and its virtual absence from the nonmalarious highlands of PNG suggest the role of malaria as the selective factor in maintaining alpha(+)-thalassemia. If this selective pressure is still operating, and since alpha(+)-thalassemia has no apparent homozygous disadvantage, the abnormal haplotype (-alpha/) will be in the process of fixation in this population.

Gene Deletion↗
PubMed1981

Genetic studies on some tribes of the Telangana region, Andhra, Pradesh, India.

Phenotype distributions and gene frequencies of nine red cell enzyme systems and haemoglobin are presented for six tribal populations from the Telangana region of Andhra Pradesh. AEO, MN and Rh blood group data are presented for four of these tribes. The results have been compared with these from other Andhra Pradesh tribal Populations. The Yerukula tribe are notable for the presence of PGM7 1 at polymorphic frequency, the occurrence of a single example of PGM10 2 and the absence of Hbs.

Blood Group Antigens↗
PubMed1981

The frequency of private electrophoretic variants and indirect estimates of mutation rate in scheduled tribes from South India.

Data on private electrophoretic variants for 18 Scheduled Tribe populations from south India have been utilized to estimate mutation rate by two indirect procedures. The values of mu for the total pooled data are 0.150 x 10(-6) and 0.264 x 10(-6)/locus per generation by the methods of Kimura and Ohta30 and Nei44 respectively. Three different groups of these tribes yield the unweighted average values of mu as 0.193 x 10(-6) and 0.410 x 10(-6)/locus per generation by the two methods given above. The estimates on individual populations, however, show a wide variability, even if only the non-zero results are considered. The unweighted average of these individual tribe estimates is an order of magnitude higher than the estimates obtained for the total populations of all the 18 tribes. The problems involved in estimating mutation rate from protein data using indirect methods in tribal populations of India are considerable because of their levels of detribalization and acculturation. The validity of the low values of mu in these tribes, in comparison with the much higher estimates for the populations from the other parts of the world, is discussed.

Electrophoresis↗
PubMed1981

Frequency of private electrophoretic variants and indirect estimates of mutation rate in Papua New Guinea.

Data on rare and private electrophoretic variants have been used to estimate mutation rates for populations belonging to 55 language groups in Papua New Guinea. Three different methods yield values of 1.42 x 10(-6), 1.40 x 10(-6), and 5.58 x 10(-6)/locus per generation. The estimates for three islands populations off the north coast of New Guinea--Manus, Karkar, and Siassi--are much lower. The variability in mutation rates estimated from rare electrophoretic variants as a function of population size is discussed. The mean mutation rate in Papua New Guinea is less than half the estimates obtained for Australian Aborigines and Amerindians.

Enzymes↗
PubMed1979

The frequency of private electrophoretic variants in Australian aborigines and indirect estimates of mutation rate.

The number of "private" electrophoretic variants of enzymes controlled by 25 loci has been used to obtain estimates of mutation rate in Australian Aborigines. Three different methods yield values of 6.11 X 10(-6), 2.78 X 10(-6), and 12.86 X 10(-6)/locus per generation for the total sample of Aborigines. One tribal population of Waljbiri in central Australia gives values of 2.99 X 10(-6) and 2.04 X 10(-6) for two of the methods, the third being unapplicable. The mean mutation rate for the total Aboriginal sample of 7.25 X 10(-6) is very similar to the value obtained by Neel and his colleagues for Amerindians in South America.

Australia↗
PubMedDate not supplied

Occurrence of the erythrocyte band 3 (AE1) gene deletion in relation to malaria endemicity in Papua New Guinea.

South-east Asian ovalocytosis status was determined in 1629 individuals originating from 12 different geographical areas of Papua New Guinea, representing different ethnic groups and degrees of malaria endemicity. This was achieved by using polymerase chain reaction amplification to demonstrate a 27 base pair deletion in the erythrocyte band 3 (AE1) gene. By using this method, the prevalence of erythrocyte band 3 gene deletion was determined to range from zero in both the lowland inland area of Wosera, East Sepik Province and the highland region of Goroka, Eastern Highlands Province to 35% on the north coast of Madang Province. In general, the prevalence correlated well with altitude, being highest on the coast where malaria transmission is high, intermediate in the lowlands, and lowest in the non-malarious highlands. However, Wosera, a lowland area in the Sepik River Plains, which is hyperendemic for malaria, was an exception in that no ovalocytosis was detected. These results largely confirm the prevalence rates that have been reported in the past using microscopy. In keeping with the autosomal dominant mode of inheritance, the male:female ratio was 1.02 and no homozygote was detected, indicating that homozygosity for the ovalocytosis band 3 gene deletion is lethal.

Adolescent↗
PubMedDate not supplied

Factors affecting electromorph mutation rates in man: an analysis of data from Australian Aborigines.

The constraints of molecular size and structure on the relative magnitudes of electromorph mutation rates as calculated indirectly have been studies using data for Australian Aborigines. The role of sample size in detecting rare electromorphs is important. In addition, subunit size shows a positive and subunit number a negative correlation with mutation rate. The differences in mutation rates were 2--9-fold when calculated for different categories of the data. The importance of physicochemical constraints are discussed.

Alleles↗
PubMedDate not supplied

Rare allele heterozygosity and relative electromorph mutation rates in man.

Previous studies of human populations have failed to find a significant relationship between genetic variability, as measured by total heterozygosity, and cistron size, as measured by subunit molecular weight of proteins, but the number of different rare alleles in human populations has been shown to be correlated with subunit size. The present paper examines these relationships further, utilizing data on electrophoretic variants at 27 loci for 12 human populations with a total of 800 000 individual system observation. The results indicate that, if genetic variability is measured by rare allele heterozygosity instead of total heterozygosity, there is a significant correlation with subunit size. In addition, there are significant differences for rare allele heterozygosity between multimeric and monomeric proteins, the range of variability being less in the multimers (and in the total) than for monomers. Finally, rare allele heterozygosity has a much bigger range of variability than the range of subunit size. By contrast, the range of rare allele heterozygosity between populations is less than ten-fold, a factor not evident in effective population sizes. Both interlocus and interpopulational estimates of relative electromorph mutation rates (REMR) have been calculated, utilizing the distributions of the number of different rare alleles as well as rare allele heterozygosity. The range of these estimates are much lower than the estimates given by Zouros (1979) using total heterozygosity as input.

Alleles↗