Electrophoretically detectable variation in the fungus Neurospora intermedia has been surveyed among isolates from natural populations in Malaya, Papua, Australia and Florida. The principal result is a pattern of genetic variation within and between populations that is qualitatively no different than the well documented patterns for Drosophila and humans. In particular, there is a high level of genetic variation, the majority of which occurs at the level of local populations. Evidence is presented which argues that N. intermedia has a population structure analogous to that of an annual vascular plant with a high level of vegetative reproduction. Sexual reproduction appears to be a regular feature in the biology of the species. Substantial heterokaryon function seems unlikely in natural populations of N. intermedia. Theoretical considerations concerning the mechanisms underlying the observed pattern of variation most likely should be consistent with haploid selection theory. The implications of this constraint upon the theory are discussed in detail, leading to the presentation of a model based upon the concept of environmental heterogenicity. The essence of the model, which is equally applicable to haploid and diploid situations, is a shifting distribution of multiple adaptive niches among local populations such that a given population has a small net selective pressure in favor of one allele or another, depending upon its particular distribution of niches. Gene flow among neighboring populations with differing net selective pressures is postulated as the principal factor underlying intrapopulational allozyme variation.
All subspecies of black rats (Rattus rattus) used in the present study are characterized by having large and clear C-bands at the centromeric region. The appearance of the bands, however, is different in the subspecies. Chromosome pair No. 1 in Asian type black rats (2n=42), which are characterized by an acrocentric and subtelocentric polymorphism, showed C-band polymorphism. In Phillipine rats (R. rattus mindanensis) the pair was subtelocentric with C-bands, but in Malayan black rats (R. rattus diardii) it was usually acrocentric with C-bands. In Hong-Kong (R. rattus flavipectus) and Japanese black rats (R. rattus tanezumi) it was polymorphic with respect to the presence of acrocentrics with C-bands or subtelocentrics without C-bands. The other chromosomes pairs showed clear C-bands, but in Hong-Kong black rats the pairs No. 2 and 5 were polymorphic with and without C-bands. In Japanese black rats, 6 chromosome pairs (No. 3, 4, 7, 9, 11 and 13) were polymorphic in regard to presence and absence of C-bands, but the other 5 chromosome pairs (No. 2, 5, 6, 8 and 10) showed always absence of C-bands. Only pair No. 12 usually showed C-bands. C-bands in small metacentric pairs (No. 14 to 20) in Asian type black rats generally large in size, but those in the Oceanian (2n=38) and Ceylon type black rats (2n=40) were small. In the hybrids between Asian and Oceanian type rats, heteromorphic C-bands, one large and the other small, were observed. Based on the consideration of karyotype evolution in the black rats, the C-band is suggested to have a tendency toward the diminution as far as the related species are concerned.
The jungle habitat of the Temuan aborigines harbors a variety of infectious diseases, the most notable being malaria. Our study of 15 genetic systems in the Temuan revealed substantial polymorphism and within-population genetic diversity. The polymorphisms for Hb beta, G6PD, and El are of interest in regard to genetic adaptation to malaria. Among the polymorphisms investigated we conclude that G6PD deficiency and elliptocytosis are likely to have malaria-resistant effects as evidenced by their low association with malarial parasitemia or their higher frequency in adults than in children. These findings suggest that the malarial habitat of the Temuans is livable in the long range sense for them because of the cluster of malaria-resistant alleles in their gene pool (G6PD)-, El, and possibly, but not tested here because of its low frequency, Hb beta E). The same condition probably holds for the Semai, the nearest aborigine neighbors of the Temuan (although the Semai have not been tested for malarial parasitemia and for these polymorphisms simultaneously), since the Semai have substantial Hb betaE, G6PD-, and El. The Temuan have a cultural identity system of rituals, beliefs, and certain aspects of language which effectively isolates them genetically from Malays and other nonaborigines. This system hinders the dilution of the malaria-resistant alleles of the Temuan gene pool with the malaria-susceptible alleles of the nonaborigine gene pools.
The salivary chromosomes of four species of the nasuta complex of Drosophila, D. sulfurigaster albostrigata, D, kohkoa, D. albomicans, and D. kepulauana were studied and chromosome maps of each species are presented; the maps of the latter three species are based on the map of D. sulfurigaster albostrigata. Three of the species D. sulfurigaster albostrigata, D. albomicans, and D. kohkoa were shown to be highly polymorphic for chromosomal inversions while the available evidence indicated that D. kepulauana is much less polymorphic. These facts are correlated with the geographic distribution of the species. Transitional homoselection has not been complete in the evolution of three of the species since D. sulfurigaster albostrigata, D. kohkoa, and D. albomicans have a number of naturally occurring polymorphisms in common.
alpha1-Antitrypsin types were determined in 200 individual specimens of Malaysian Macaca irus. We found the pattern B in 76 samples, BC in 116, and C in 8. Assuming that these patterns are determined by codominant alleles at one locus, this distribution constitutes a significant (P less than 0.001) deviation from Hardy-Weinberg equilibrium, because of an excess of BC and low prevalence of C. We found no clear evidence for the presence of alpha1-antitrypsin deficiency comparable to the situation in man.
Malaysians of Malay, Chinese, and Indian ancestries were electrophoretically phenotyped for Amy1 and saliva esterase region 1 (Set-1) from saliva, Amy2 from plasma, soluble and mitochondrial GOT and PGM3 from leukocyte and placenta. Kadazans and Bajaus, the indigenous people of Sabah, East Malaysia were surveyed for Amy2. Three types of variants were observed for Amy1, one type for Amy2. Only Indians were found to be polymorphic for Amy1. Two GOTs 2-1 and three GOTm 2-1 variants were found among 281 Chinese while three GOTm 2-1 variants were found among 311 Malays. Malaysian Malays, Chinese, and Indians were found to be polymorphic for Set-1 and PGM3. The gene frequencies in Malays are Set-1F=0.601 +/- 0.021, Set-1S = 0.399 +/- 0.021; PGM13 = 0.788 +/- 0.020, PGM23 = 0.212 +/- 0.020; in Chinese Set-1F = 0.497 +/- 0.028, Set-1S = 0.503 +/- 0.028; PGM13 = 0.745 +/- 0.24, PGM23 = 0.255 +/- 0.024; in Indians, Set-1F = 0.449 +/- 0.031, Set-1S = 0.551 +/- 0.031; PGM13 = 0.755 +/- 0.029, PGM23 = 0.245 +/- 0.029.
812 West Malaysian Orang Asli belonging to four ethnic groups were surveyed for adenosine deaminase (ADA; EC 3.5.4.4) using starch gel electrophoresis. Only the common ADA1 and ADA2 alleles were found, with the frequencies of the latter being 0.025, 0.103, 0.115 and 0.028 in the Semai, Semelai, Temuan, and Jakun groups, respectively. A new 'breeding genetic distance' was applied to these gene frequencies and the Semelai and Temuan were found to be more closely related to each other, and to have considerably more evolutionary flexibility on this scale of 'micro-evolution' than the other two groups. The Semai and Jakun were more similar to each other on the basis of these ADA gene frequencies.
Four red cell enzyme systems were studied in Malaysian mothers and their newborn belonging to three racial groups, the Malays, Indians and Chinese. No significant heterogeneity was observed in the distribution of phosphoglucomutase (PGM1), adenosine deaminase (ADA), 6-phosphogluconate dehydrogenase (6PGD) and acid phosphatase (AP) phenotypes between mothers and their newborn of the three groups. Pooled mother and child acid phosphatase data show a significant heterogeneity between the Malays and Chinese, and between the Malays and Indians. This is comparable to previous studies conducted. For the placental phosphoglucomutase (PGM3) system, a significant heterogeneity was observed between the Chinese and Malays only. No significant heterogeneity was detected in the distribution of PGM1, ADA and 6PGD phenotypes among Malays, Chinese and Indians.
Human alcohol dehydrogenase ADH2 and ADH3 were investigated in liver and stomach specimens of Chinese and Indians from West Malaysia. Eight-nine percent of the Chinese carry the atypical ADH2 type, a proportion very similar to that reported in Japanese. However, among 43 Indian specimens there was not a single case of atypical ADH2. In Indians, the gene frequency of ADH13 is 0.64 and of ADH23 0.36, similar to the frequencies in Caucasians, whereas in Chinese, the gene frequency for ADH13 and ADH23 is 0.91 and 0.09, respectively. We also report some unusual enzymatic characteristics in the course of our study.
The genetics of glucosephosphate isomerase (E.C. 5.3.1.9) in two strains (Malaysian and Taiwan) of Aedes togoi is reported. Three electrophoretic phenotypes were presented in both sexes. The zymogram patterns were identical in both strains of A. togoi. The phenotypes were governed by a pair of codominant alleles. The allele frequency of the slow-moving band was 0.63 in the Malaysian strain adn was 0,86 and 0.82 in F161 and F169 generations, respectively, of the Taiwan strain. The sample studied was in good accord with Hardy-Weinberg expectation.
Three human saliva genetic markers, namely, salivary peroxidase (SAPX), Pm, and Ph proteins, were investigated in the three major ethnic groups of Malaysia: Malays, Chinese, and Indians. For Pm, the allelic frequencies of Pm+ for Malays, Chinese, and Indians are 0.385 +/- 0.030, 0.282 +/- 0.026, and 0.289 +/- 0.026 respectively. For Ph, the allelic frequencies of Ph+ are 0.082 +/- 0.016 for Malays, 0.109 +/- 0.017 for Chinese, and 0.062 +/- 0.013 for Indians. For SAPX, the allelic frequencies of SAPX1 in Malays, Chinese, and Indians are 0.762 +/- 0.027, 0.755 +/- 0.027, and 0.723 +/- 0.026 respectively.