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1.
Liang Zhong Chen Simon Easteal Philip G. Board Kim M. Summers Kuldeep K. Bhatia Robert L. Kirk 《Human genetics》1990,85(1):89-97
Summary We have determined the various haplotypic combinations between alleles as well as restriction fragment length polymorphisms of two linked genetic markers, albumin and vitamin D-binding protein or group-specific component, in a number of Asian-Pacific populations. Using the partial maximum likelihood method, we constructed a phylogenetic network from the haplotype frequencies to assess relationships among the populations sampled. No systematic linkage disequilibrium was detected between most of the combinations, suggesting a lack of operation of any selection pressure at the two loci. The phylogenetic analysis confirmed the known interrelationships among various populations in the Asian-Pacific region. The Australian aborigines clustered closely with the non-Austronesian-speaking highlanders from Papua New Guinea, as expected. Similarly, the Austronesian-speaking Polynesians, Micronesians, and the Southeast Asians branched off together as a separate group. The position of the Austronesian-speaking Tolais from New Britain with respect to other populations from the Southwest Pacific was anomalous. The Tolais revealed a strong affinity with the Australian aborigines, which is inexplicable. The populations from China formed a tight cluster with other populations from the Asian-Pacific region. Genetic interrelationships of these populations with the white Australians were remote, which is in accordance with the known affinities of various human racial groups. 相似文献
2.
Summary A new restriction fragment length polymorphism detected with the restriction endonuclease BglII (AGATCT) is presented. 相似文献
3.
The effect ofl-ascorbic acid on the biosynthesis of aflatoxin inAspergillus parasiticus was studied. Ascorbic acid at lower concentrations did not inhibit the growth of fungus but markedly induced aflatoxin biosynthesis. At a concentration of 1000 ppm of ascorbic acid, 4.8-fold higher levels of aflatoxin were detected. Copper did not enhance the induction of toxin synthesis by ascorbic acid when added to the growth medium. Ascorbic acid at 1000 ppm was also found to induce aflatoxin synthesis in resting mycelia. Chloroform (1% vol/vol) was found to induce aflatoxin synthesis under similar conditions. Ascorbic acid in the presence of ferrous ion can cause lipid peroxidation, which in turn is responsible for the induction of aflatoxin synthesis. During the induction of aflatoxin synthesis by ascorbic acid, the uptake of carbon source (acetate) was not affected. This observation suggests that on ascorbic acid treatment a precursor or an intermediate of aflatoxin biosynthesis is synthesized in vivo and is responsible for the higher levels of toxin without increasing the uptake of acetate. 相似文献
4.
HLA and autoimmunity in North Indian type I (insulin-dependent) diabetic multiplex families 总被引:1,自引:0,他引:1
The HLA haplotype segregation and autoantibody spectrum in 7 type I (insulin-dependent) diabetic multiplex families of North Indian origin were determined. Of the total of 17 diabetic sibs, 7 shared both haplotypes and 3 shared one haplotype with the proband. No HLA-non-identical sibs were observed. This distribution of haplotypes was non-random (P approximately equal to 0.005). The mode of inheritance was compatible with an autosomal recessive model, while a dominant model was unlikely. Pancreatic islet-cell antibodies were found in 23.5% of affected sibs, but in no healthy family member. A high incidence of other autoantibodies (parietal-cell and thyroglobulin/thyroid microsomal antibodies) was detected in both the diabetic patients (26.3%), and in healthy first-degree relatives (22.2%). These findings emphasize the role of HLA-linked genes and autoimmunity in the pathogenesis of type I diabetes in North India. 相似文献
5.
6.
The number of antibody molecules on individual erythrocytes was counted in A1, A2, A3 B and A group individuals using immunoautoradiography (IAR) and monoclonal IgM anti-A1. Quantitation was also done for A group pregnant women. The number of antibody molecules on different red cells of an individual varied widely. Gross variations were also noted in cells of different individuals from one and the same group. The mean values of the uptake of the number of antibody molecules showed the following range A1 greater than A2 greater than Ax greater than A3B. When compared to the average for total A1 adults, red cells of pregnant women and newborn infants showed a 10.7% and 19.7% reduction respectively, in antibody uptake. The mean number of antibody molecules per A1 adult red cells was 5.6 +/- 3 X 10(4), while A2 had 0.85 +/- 0.35 X 10(4) molecules, thus showing a significant quantitative variation. 相似文献
7.
Extremely high frequencies of alpha-globin gene deletion in Madang and on Kar Kar Island, Papua New Guinea. 总被引:3,自引:0,他引:3
P T Yenchitsomanus K M Summers K K Bhatia J Cattani P G Board 《American journal of human genetics》1985,37(4):778-784
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. 相似文献
8.
9.
N. M. Blake B. R. Hawkins R. L. Kirk K. Bhatia P. Brown R. M. Garruto D. C. Gajdusek 《American journal of physical anthropology》1983,62(4):343-361
As part of a multidisciplinary survey of populations in the Banks and Torres Islands of Vanuatu and the Southern and Central Districts of the Solomon Islands, nearly 2,400 persons have been tested for ABO blood groups and a number of serum protein and red cell enzyme genetic marker systems. For the ABO system, the populations are characterized in general by high gene O and low gene B frequencies except in two of the Polynesian Outlier Islands, Rennell and Bellona, which have high frequencies of B. Among the serum proteins, several alleles have distributions indicating significant movement of people between islands. These include Albumin New Guinea and the transferrin alleles Tf, and Tf, and Tf. Similar specific alleles for red cell enzymes also show distributions reflecting interisland population movement as well as contact with persons from outside the southern Pacific region. Examples are ACP in the acid phosphatase system, PGM and PGM, PGM and PGM, PGK4 and also HbJTongariki. The data available for 11 polymorphic systems were used to generate genetic distances. Of the four Polynesian Outlier Islands, Anuta is most remote genetically, with Rennell and Bellona also relatively isolated. The fourth Polynesian Outlier, Tikopia, occupies a position genetically close to the Melanesian populations of the Banks and Torres Islands and the southern Solomons. The history of early European contact and voyaging in the Pacific, as well as archaeological and linguistic evidence and local legends, indicate that significant movements of people occurred between islands and provided opportunities for genes to be introduced from Europeans, Africans, and Asians. The genetic marker studies give evidence for genes from all these sources, though at a low level. Despite this admixture, the Polynesian Outlier and Melanesian populations have preserved their own distinctive genetic patterns. 相似文献
10.
Summary Five rates of limestone and 4 rates of fertilizers were used in a split-plot design to study their effects under field conditions
on Mo, Cu, B, Mn, and Zn levels in mixed forage tissue and soil, and on the forage yield. An increase in soil pH resulted
in an increase in Mo and Cu content of plant tissue while B, Mn, and Zn decreased. The micro-nutrient content of the tissue
increased as the harvesting season progressed. Increasing rates of applied fertilizer did not affect the micro-nutrient content
of the forage tissue or soil.
Liming to a pH of 5.6 and above reduced the availability of Mn and Zn in the soil. In general, the available B was low at
pH values greater than 6.1. Lime did not affect the quantities of Mo and Cu in the soil. Manganese is supplied in large quantities
by limestone and is not apt to be deficient in limed soil. However, addition of B and Zn may be required on the high pH soils
of Eastern Canada in future. Molybdenum was adequate where the soil was limed to a pH of 6.1 or greater.
The dry-matter yield of forage increased significantly with successive increases in lime up to pH 6.6 and with each increment
of fertilization.
Contribution No.226, Research Branch, Research Station, P.O. Box 1210, Charlottetown, P.E.I. and No.166, Experimental Farm, Nappan, N.S. 相似文献