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1.
Batsheva Bonn-Tamir Sarah Ashbel Shulamit Bar-Shani 《American journal of physical anthropology》1978,49(4):465-471
One hundred and ninety-six Moroccan Jews now settled in Israel were typed for 7 blood groups, 12 red cell enzymes and 2 plasma protein systems. Their blood group picture is in agreement with results previously obtained on different samples of Moroccan Jews: rather high B in ABO, somewhat elevated frequencies of cDE and cDe in Rh and K in Kell. Differences in various blood markers exist between them and other North African Jewish communities. This fact, together with data on disease distribution and HLA frequencies, supports our assumption that Jews in the North African diaspora lived as small secluded isolates even within the same geographical zones. Comparisons with meager data on the neighboring non-Jewish populations do not disclose any resemblance to either Arab or Berber inhabitants of Morocco. 相似文献
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3.
Scarano FR 《Annals of botany》2002,90(4):517-524
The Brazilian Atlantic rainforest consists of a typical tropical rainforest on mountain slopes, and stands out as a biodiversity hotspot for its high species richness and high level of species endemism. This forest is bordered by plant communities with lower species diversity, due mostly to more extreme environmental conditions than those found in the mesic rainforest. Between the mountain slopes and the sea, the coastal plains have swamp forests, dry semi-deciduous forests and open thicket vegetation on marine sand deposits. At the other extreme, on top of the mountains (>2000 m a.s.l.), the rainforest is substituted by high altitude fields and open thicket vegetation on rocky outcrops. Thus, the plant communities that are marginal to the rainforest are subjected either to flooding, drought, oceanicity or cold winter temperatures. It was found that positive interactions among plants play an important role in the structuring and functioning of a swamp forest, a coastal sandy vegetation and a cold, high altitude vegetation in the state of Rio de Janeiro. Moreover, only a few species seem to adopt this positive role and, therefore, the functioning of these entire systems may rely on them. Curiously, these nurse plants are often epiphytes in the rainforest, and at the study sites are typically terrestrial. Many exhibit crassulacean acid metabolism. Conservation initiatives must treat the Atlantic coastal vegetation as a complex rather than a rainforest alone. 相似文献
4.
Investigations on the ethnic variability of the ABO blood group polymorphism in Iran 总被引:2,自引:0,他引:2
H Walter D D Farhud H Danker-Hopfe P Amirshahi 《Zeitschrift für Morphologie und Anthropologie》1991,78(3):289-306
112 Iranian population samples with a total of 600954 individuals are analyzed concerning the ethnic variability of ABO allele frequencies. The genetic heterogeneity within and between these population samples is considerable. This heterogeneity is discussed with regard to the ethnohistory of Iran. The most striking ABO allele frequencies are observed in Assyrians, Armenians and Zoroastrians, which differ extremely from that of all the other hitherto studied ethnic groups of Iran. Obviously varying ABO allele frequencies are seen also in Yazdis as well as in Turkomans and Arabs living in Iran. And finally the Iranian Jews reveal clear frequency differences in comparison with all the other Iranian population groups. It can be assumed that the specific ABO allele frequencies found in the above mentioned ethnic groups are connected with their different geographical origin as well as with their marked endogamy. 相似文献
5.
Peter S. Ashton 《Biodiversity and Conservation》2010,19(2):343-356
Borneo, the World’s fourth largest island, represents a continental mass sandwiched between volcanic arcs. Patterns of tree
species richness, here proposed as proxy for overall biodiversity, and endemism within the island are described and interpreted
with special reference to Dipterocarpaceae. Most of Borneo’s surface is sedimentary shales, mostly inland, and sandstones,
mostly coastal, deposited in past epicontinental seas. The shales mainly support the regional West Malesian (Sundaland) tree
flora, while the Neogene coastal hills, especially in the north-west, support the richest communities which are also richest
in endemics. The forests of these hills, which include the richest tree communities in the Old World and are therefore of
global significance, are accessible and critically endangered. Priorities for their future management are outlined. 相似文献
6.
J. S. Murty B. Muralidhar J. D. Goud P. Jagan Mohan Rao B. Ramesh Babu V. Srinivas Rao 《American journal of physical anthropology》1993,90(2):169-183
Gene diversity and genetic structure of tribal populations of Andhra Pradesh, India, have been analyzed under a hierarchical model consisting of five regions of the state, tribes within the regions, and local subpopulations within the tribes. Average gene diversity has been estimated from gene frequency data for 15 polymorphic loci by using nested gene diversity analysis of GST. The intralocation coefficient of gene diversity was estimated at 96% of the total, whereas the intertribal, within—and between—regional gene diversities were found to be only 1.90, 0.95, and 1.43%, respectively. The estimate of gene diversity was higher for loci with higher degrees of polymorphism such as ABO, MN, ESD, and PTC and lower for loci with low-level polymorphism and extreme gene frequencies such as Hb, Tf, PHI, 6PGD, and Hp. The nature of selective preference or neutrality at the loci seems to be important in this respect. Tribes of the plains exhibit the least gene diversity, apparently because of higher gene flow among them. The contribution of loci with intermediate gene frequencies in intertribal and regional gene diversity was found to be higher than for loci with extreme allelic frequencies. These results suggest that the most significant component of variation is between individuals within locations and that variation between local subpopulations is negligible in the genetic structure of a population. Forces like selection, gene flow and drift also influence the diversity depending upon the nature of the locus. © 1993 Wiley-Liss, Inc. 相似文献
7.
The population of Nicobar is not a single random mating population but divided into a number of subpopulations within each of which essentially random mating takes place. Heterogeneity tests indicate that there is a significant difference among subpopulations for the ABO blood group system but not for the MN system. The overall gene frequencies of the ABO system were: r = 0·914; p = 0·033; q = 0·053. The gene frequencies of the MN system are much more consistent in the area as a whole than in the ABO system. The gene frequencies of the MN system were: M = 0·92 and N = 0·08. The Wahlund's principle yields the value of Ø = 0·0358 for the MN system and the unweighted mean value of Øs equals 0·0301 for the ABO system. The founder effect may have a far greater effect than the effects of chance in the genetical structure of Nicobar subpopulations. 相似文献
8.
Tripathy V Satapathy KC Gupta R 《Human biology; an international record of research》2006,78(2):229-233
A study of ABO and Rh D polymorphisms was conducted on 923 Tibetans living in exile in four different places (both high and low altitudes) in India. The frequencies of alleles p, q, and r for the ABO blood group system were found to be 0.1295, 0.2544, and 0.6152, respectively, and for alleles D and d of the Rh blood group system the allele frequencies were 0.9428 and 0.0572, respectively, for the total data. No significant difference was found for the allele frequencies among the four places for the two blood group systems. The allele frequencies were in Hardy-Weinberg equilibrium for the ABO blood group system and show East Asian affinity for the Tibetans. 相似文献
9.
The Distribution of Microbial Communities in Anaerobic and Aerobic Zones of a Shallow Coastal Plain Aquifer 总被引:2,自引:0,他引:2
Abstract
Randomly amplified polymorphic DNA (RAPD) fingerprinting was used to determine the genetic similarity of whole-community DNA
extracts from unattached microorganisms in several groundwater wells. The study site was a shallow coastal plain aquifer on
the Eastern Shore of Virginia that contains distinct regions of anaerobic and aerobic groundwater. Several wells in each region
were sampled, and principal component and cluster analyses showed a clear separation of the microbial communities from the
two chemical zones of the aquifer. Within these zones, there was no relationship between the genetic relatedness of a pair
of communities and their spatial separation. Two additional sets of samples were taken at later times, and the same clear
separation between communities in the different zones of the aquifer was observed. The specific relationships between wells
within each zone changed over time, however, and the magnitude and direction of these changes corresponded to concurrent changes
in the groundwater chemistry at each well. Together, these results suggest that local variation in groundwater chemistry can
support genetically distinct microbial communities, and that the composition of the microbial communities can follow seasonal
fluctuations in groundwater chemistry.
Received: 25 May 1999; Accepted: 4 August 1999; Online Publication: 9 December 1999 相似文献
10.
Apple farming is an important activity and profession of farmer communities in the Himalayan states of India. At present, the traditional apple farming is under stress due to changes in climate. The present study was undertaken in an Indian Himalayan state, Himachal Pradesh, with the major aim of studying perceptions of farmers on the effects of climate change on apple farming along the altitudinal gradient. Through questionnaire survey, the perceptions of farmers were recorded at low hills (<2500 m), mid-hills (2500–3000 m), and upper hills (>3000 m). At all elevation range the majority of farmers reported that there was increase in atmospheric temperature, and hence at low hills 72% farmers believed that this increase in temperature was responsible for decline in fruit size and so that the quality. Thirty five percent farmers at high hills and 30% at mid hills perceived frost as a major cause for damaging apple farming whereas at low hills 24% farmers perceived hailstorm as the major deterrent for apple farming. The majority of farmers, along the altitude (92% at high hills, 79% at mid hills and 83% at low hills), reported decrease in snowfall. The majority of farmers at low altitude and mid altitude reported decline in apple farming whereas 71% farmers at high hill areas refused decline in apple farming. About 73–83% farmers admitted delay in apple’s harvesting period. At mid hills apple scab and at low hills pest attack on apple crops are considered as the indicators of climate change. The change in land use practices was attributed to climate change and in many areas the land under apple farming was replaced for production of coarse grains, seasonal vegetables and other horticulture species. Scientific investigation claiming changes in Indian Himalayan climate corroborates perceptions of farmers, as examined during the present study. 相似文献
11.
This study compares the segregation of the ABO and Rh systems between malformed newborns and a control group with two purposes: (1) to evaluate the participation of genetic factors associated with these blood groups in the production of congenital malformations, and (2) to prove, indirectly, the existence of reproductive losses associated with congenital malformations. The newborns and their mothers were typed for ABO and Rh groups. Gene frequencies were similar in malformed and control newborns. In the female malformed newborns, an excess of O-B pairs and a deficit of B-B pairs in the ABO system, and an excess of Rh(-)-Rh- pairs in the Rh system were found. 相似文献
12.
Anthropologists have assumed that reduced genetic diversity in extant Native Americans is due to a founder effect that occurred during the initial peopling of the Americas. However, low diversity could also be the result of subsequent historical events, such as the population decline following European contact. In this study, we show that autosomal DNA from ancient Native American skeletal remains can be used to investigate the low level of ABO blood group diversity in the Americas. Extant Native Americans exhibit a high frequency of blood type O, which may reflect a founder effect, genetic drift associated with the historical population decline, or natural selection in response to the smallpox epidemics that occurred following European contact. To help distinguish between these possibilities, we determined the ABO genotypes of 15 precontact individuals from eastern North America. The precontact ABO frequencies were not significantly different from those observed in extant Native Americans from the same region, but they did differ significantly from the ABO frequencies in extant Siberian populations. Studies of other precontact populations are needed to better test the three hypotheses for low ABO blood group diversity in the Americas, but our findings are most consistent with the hypothesis of a founder effect during the initial settlement of this continent. 相似文献
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14.
Attached algae were examined from eight sites in Central Colorado streams (five sites on St. Vrain Creek and three on the
Snake River) between June and November, 1995. The sites ranged in elevation from 1600 m to 3500 m a.s.l.(plains zone to alpine
zone). Seasonal variation in algal communities were qualified in forms of species composition and abundance (cell counts and
biovolumes). The Ochiai coefficient of similarity was used to estimate degree of similarity between communities at different
times, on different streams, and at different locations on the same stream. The composition of communities across streams
for alpine and foothills zones was very close, but montane communities differed greatly across streams (similarity < 0.1).
Temporal variability of attached algae was almost absent in the alpine zone, but was high in other zones. The composition
of the alpine community in August developed downstream with a temporal shift: October in the montane and foothills zones,
November in the plains zone.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
Tom Smith Kuldeep Bhatia Madhuri Prasad George Koki Michael Alpers 《American journal of physical anthropology》1994,95(2):155-168
Class I HLA gene frequencies show considerable variation over short geographical distances in Papua New Guinea. Hypotheses to account for this invoke natural selection, population structure, the pattern of population movement, or past demographic changes. To determine the role of the various factors in shaping this distribution, we have studied correlations between HLA-based genetic distances, geographical distances, altitude, and linguistic differences in Papua New Guinea. Linguistic differences at the family or stock level within the Trans-New Guinea Phylum generally correspond to genetic differences. However, on the basis of their HLA gene frequencies, speakers of Austronesian (AN) languages do not form a distinct group of populations. Linguistic variation and spatial autocorrelation do not fully account for the altitudinal cline differences noted in gene frequencies, particularly at the HLA-A locus. We propose that the distribution of HLA gene frequencies in Papua New Guinea is partially under the control of selection operating differentially along the altitude gradient. © 1994 Wiley-Liss, Inc. 相似文献
16.
Study of red blood cell and serum enzymes in five Pyrenean communities and in a Basque population sample 总被引:2,自引:0,他引:2
H Vergnes J Constans J C Quilici P Lefèvre-Witier J Sevin M Stevens 《Human heredity》1980,30(3):171-180
Until recently, no data on genetic polymorphisms in the populations living on the northern side of the Pyrenees have been available, except for the Basques. Several investigations were done lately on rural communities in various geographic zones in the Pyrenees from the eastern to the western part. In this paper, the results for the following enzyme polymorphisms are reported: acid phosphatases, AK, ADA, PGM1 and PGM2, 6PGD, NADH diaphorase, SOD, MDH, TGP, G6PD, C5 esterase (E2 locus), serum cholinesterase (E1 locus). Significant variation in gene frequencies was observed over the distinct geographic zones for the main polymorphic system. Furthermore, some rare alleles were found: a new G6PD variant (Luz-Saint-Sauveur), the presence of ADA3 and ADA5 alleles in two groups of the Central Pyrenees, a Dia2 gene among Basques and in the Pays de Sault, a high rate of Ea1 allele in the Basque group. The values obtained for the degree of heterozygosity are in agreement with the relative isolation of the different groups studied and confirm the importance of sociocultural factors in the evolution of the genetic background of rural communities in Europe. 相似文献
17.
海南岛景观空间结构分析 总被引:82,自引:9,他引:73
景观空间结构分析是景观生态学研究的核之一。运用景观生态学原理,借助地理住处系统技术,选取斑块密度、边缘密度、分维数、景观多样性、景观优势度和平均接近指数等指标,分析了海南岛不同景观类型的空间分布和空间格局,特征,探讨了该地区人类活动与景观结构之间的关系。结果显示从中部山地圈带到台地丘陵圈带到沿海平原圈带,平均接近指数从9231.493到1993.585到481.251,呈明显减少趋势,景观破碎程度增大;景观多样性指数从0.787到1.370到1.537,呈增大趋势;平均斑块分维数从1.067到1.064到1.059,呈减少趋势,另外,结果也显示从中部山地圈沿海平原圈带的人工景观类型优势度明显增大,表明受人类活动影响愈来愈强烈。 相似文献
18.
MORBILLIVIRUS INFECTION IN BOTTLENOSE DOLPHINS: EVIDENCE FOR RECURRENT EPIZOOTICS IN THE WESTERN ATLANTIC AND GULF OF MEXICO 总被引:1,自引:0,他引:1
Pádraig J. Duignan Carol House Daniel K. Odell Randall S. Wells Larry J. Hansen Michael T. Walsh David J. St . Aubin Bert K. Rima Joseph R. Geraci 《Marine Mammal Science》1996,12(4):499-515
Morbillivirus infection is widespread among odontocetes of the western Atlantic and Gulf of Mexico. Serologic evidence of infection in bottlenose dolphins, Tursiops truncatus , was first detected during an epizootic along the mid-Atlantic coast in 1987. Here, we report recurrent epizootics in the coastal dolphin population since at least the early 1980s based on serological surveys and regional stranding frequencies. The first observed epizootic of this series occurred in the Indian and Banana Rivers in 1982 and was followed by others on the mid-Atlantic coast in 1987–1988 and in the Gulf of Mexico between 1992 and 1994. This temporal pattern of infection is likely facilitated by the population size and its fragmentation into relatively discrete coastal communities. Introduction of morbillivirus into a community with a sufficient number of naive hosts may precipitate an epizootic, depending on the potential for transmission within the group. Propagation of an epizootic along the coast is probably determined by frequency of contact between adjacent communities and seasonal migrations.
Morbillivirus antibodies were also detected in serum from offshore bottlenose dolphins. The sero-prevalence in the latter may be higher than in coastal dolphins because of their close association with enzootically infected pilot whales ( Globicephala spp.). Occasional contact between offshore and coastal dolphins may provide an epizootiologic link between pilot whales and coastal dolphin communities. 相似文献
Morbillivirus antibodies were also detected in serum from offshore bottlenose dolphins. The sero-prevalence in the latter may be higher than in coastal dolphins because of their close association with enzootically infected pilot whales ( Globicephala spp.). Occasional contact between offshore and coastal dolphins may provide an epizootiologic link between pilot whales and coastal dolphin communities. 相似文献
19.
Cattle of Dagestan are infested with several nematode species from the suborders Spirurata and Filariata, and extensiveness of the invasion depends greatly on the altitude above sea level. Level of infestation with Thelazia rhodesi, Th. gulosa, and Th. skrjabini is 38% in plains, 20% in submontane, and 5% in mountain zone. The same tendency is observed for the species Gongylonema pulchrum--45, 22, and 10%, respectively. Infestation with Setaria labiato-papillosa is 27.3% on average. Infestation with Onchocerca gutturosa and O. lienalis is 11% in plains and 3% in mountain and submontane zones; infestation with Stephanofilaria assamensis and S. stilesi in these zones is 18 and 5%, respectively. In mountain localities situated higher than 1000 m a. s. l. only G. pulchrum is occurred. 相似文献
20.
根据中国13个人口逾百万的民族及台湾高山族的红细胞血型座位的基因频率,分析了各血型系统的分化程度。结果表明,中国人群在MNSs系统上的分化十分显著。对各民族间的亲缘关系分析表明,汉族、朝鲜族、蒙古族、回族,满族和藏族等北方民族首先聚集在一起,侗族、高山族、壮族和彝族等聚集在一起,然后白族与南北两大人集聚集在一起,最后才是维吾尔族与其它人群相聚。本文以华北汉族作为蒙古人种的代表,探讨了世界上三大人种间的遗传关系,结果表明,黄种人与黑种人之间的遗传差异最小,而黑种人与白种人之间的遗传差异最大。根据基因分化系数(G_(ST))和Shannon信息测度(H),中国民族间的遗传差异均仅占中国人总遗传变异量的2%左右,这说明,绝大部分遗传变异存在于各民族之内。 相似文献