首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The genetic structure of mangrove species is greatly affected by their geographic history. Nine natural populations of Ceriops tagal were collected from Borneo, the Malay Peninsula, and India for this phylogeographic study. Completely different haplotype compositions on the east versus west coasts of the Malay Peninsula were revealed using the atpB-rbcL and trnL-trnF spacers of chloroplast DNA. The average haplotype diversity (Hd) of the total population was 0.549, nucleotide diversity (θ) was 0.030, and nucleotide difference (π) was 0.0074. The cladogram constructed by the index of population differentiation (G ST) clearly separated the South China Sea populations from the Indian Ocean populations. In the analysis of the minimum spanning network, the Indian Ocean haplotypes were all derived from South China Sea haplotypes, suggesting a dispersal route of C. tagal from Southeast Asia to South Asia. The Sunda Land river system and surface currents might be accountable for the gene flow directions in the South China Sea and Bay of Bengal, respectively. The historical geography not only affected the present genotype distribution but also the evolution of C. tagal. These processes result in the genetic differentiation and the differentiated populations that should be considered as Management Units (MUs) for conservation measurements instead of random forestation, which might lead to gene mixing and reduction of genetic variability of mangrove species. According to this phylogeographic study, populations in Borneo, and east and west Malay Peninsula that have unique genotypes should be considered as distinct MUs, and any activities resulting in gene mixing with each other ought to be prevented.  相似文献   

2.
ObjectivesTo examine whether self reported health status and use of health services varies in children of different social class and ethnic group.DesignCross sectional study from the 1999 health survey for England.Subjects6648 children and young adults aged 2-20 years.SettingPrivate households in England.ResultsLarge socioeconomic differences were observed between ethnic subgroups; a higher proportion of Afro-Caribbean, Indian, Pakistani, and Bangladeshi children belonged to lower social classes than the general population. The proportion of children and young adults reporting acute illnesses in the preceding two weeks was lower in Bangladeshi and Chinese subgroups (odds ratio 0.41, 95% confidence interval 0.27 to 0.61 and 0.46, 0.28 to 0.77, respectively) than in the general population. Longstanding illnesses was less common in Bangladeshi and Pakistani children (0.52, 0.40 to 0.67 and 0.57, 0.46 to 0.70) than in the general population. Irish and Afro-Caribbean children reported the highest prevalence of asthma (19.5% and 17.7%) and Bangladeshi children the lowest (8.2%). A higher proportion of Afro-Caribbean children reported major injuiries than the general population (11.0% v 10.0%), and children from all Asian subgroups reported fewer major and minor injuries than the general population. Indian and Pakistani children were more likely to have consulted their general practitioner in the preceding fortnight than the general population (1.86, 1.35 to 2.57 and 1.51, 1.13 to 2.01, respectively). Indian, Pakistani, Bangladeshi, and Chinese children were less likely to have attended outpatient departments in the preceding three months. No significant differences were found between ethnic groups in the admission of inpatients to hospitals. Acute and chronic illness were the best predictors of children''s use of health services. Social classes did not differ in self reported prevalence of treated infections, major injuries, or minor injuries, and no socioeconomic differences were seen in the use of primary and secondary healthcare services.ConclusionsChildren''s use of health services reflected health status rather than ethnic group or socioeconomic status, implying that equity of access has been partly achieved, although reasons why children from ethnic minority groups are able to access primary care but receive less secondary care need to be investigated.

What is already known on this topic

Children from lower socioeconomic classes and from Indian ethnic subgroups may make more use of general practitioners'' services than other childrenAfro-Caribbean, Indian, Pakistani, and Bangladeshi children are less likely to be referred to outpatient and inpatient services at hospitals than white children

What this study adds

Indian, Pakistani, and Bangladeshi children reported less acute and chronic illness, asthma, and injuries than the general population, whereas Afro-Caribbean children reported moreChildren''s self reported health status and use of health services did not vary by social classIndian and Pakistani children make more use of general practitioners'' services, but Indian, Pakistani, Bangladeshi, and Chinese children are less likely to be referred to outpatient clinicsSelf reported health status rather than socioeconomic status or ethnicity is the best predictor of use of primary and secondary services  相似文献   

3.
Recent UK Labour Force Survey data are used to investigate marriage and family formation among the white and ethnic minority populations in Britain. The different age‐sex structures of the white and ethnic minority groups are analysed and the increasing number of UK‐born or ‘second‐generation’ persons identified. Large differentials are seen between ethnic minority groups in the propensity to cohabit, marry and experience marital disruption. Average spousal age differences and the propensity to form interethnic unions are also distinctive. Resulting patterns of family and household composition are described. In particular, the data suggest important divergences between individuals of Indian and those of Pakistani and Bangladeshi ethnic origin, such that we cannot talk about the demography of the South Asian population as a whole. Comparisons of marriage patterns among ‘first‐’ and ‘second‐generation’ individuals within each ethnic group suggest some assimilation in marriage patterns among the Indian, Pakistani and Bangladeshi populations towards those of the white population.  相似文献   

4.
Discussion over marriage migration in the UK has largely focused on the South Asian groups, identified in survey data as Indian, Pakistani, and Bangladeshi. This paper uses qualitative interviews and national Labour Force Survey data to gain some insights into how UK-born Pakistani and Bangladeshi women view marriage and, in particular, marriage to a partner from their country of origin; the extent to which UK-born Indian, Pakistani, and Bangladeshi women and men marry partners from overseas and the key factors that influence this; and the effect on the level of economic activity for Indian, Pakistani, and Bangladeshi women of marriage to a UK-born/raised partner versus a partner from overseas.  相似文献   

5.
The musk shrew (Suncus murinus) is an insectivore species that inhabits tropical and subtropical Asia widely. To clarify the genetic relationship among wild musk shrew populations, we examined the electrophoretic variants of biparentally inherited genetic markers at 10 loci coding for eight blood proteins/enzymes in a total of 639 animals and compared the results obtained from the mitochondrial DNA data. The principal-component analysis performed using the allele frequency data revealed that the 17 populations could be divided into two major groups, a South Asian group and a Southeast Asian group that includes several island populations bound by Myanmar. The degrees of genetic divergence among populations were higher within the Southeast Asian group than within the South Asian group. This finding was incongruent with the mtDNA diversity. Analysis conducted at the individual level showed that a shrew from the central region in Myanmar that carries a South Asian type of mtDNA showed the electrophoretic variants specific to the Southeast Asian group, suggesting that this region is a contact zone between the two major groups.  相似文献   

6.
Utilization of multiple putatively neutral DNA markers for inferring evolutionary history of species population is considered to be the most robust approach. Molecular population genetic studies have been conducted in many species of Anopheles genus, but studies based on single nucleotide polymorphism (SNP) data are still very scarce. Anopheles minimus is one of the principal malaria vectors of Southeast (SE) Asia including the Northeastern (NE) India. Although population genetic studies with mitochondrial genetic variation data have been utilized to infer phylogeography of the SE Asian populations of this species, limited information on the population structure and demography of Indian An. minimus is available. We herewith have developed multilocus nuclear genetic approach with SNP markers located in X chromosome of An. minimus in eight Indian and two SE Asian population samples (121 individual mosquitoes in total) to infer population history and test several hypotheses on the phylogeography of this species. While the Thai population sample of An. minimus presented the highest nucleotide diversity, majority of the Indian samples were also fairly diverse. In general, An. minimus populations were moderately substructured in the distribution range covering SE Asia and NE India, largely falling under three distinct genetic clusters. Moreover, demographic expansion events could be detected in the majority of the presently studied populations of An. minimus. Additional DNA sequencing of the mitochondrial COII region in a subset of the samples (40 individual mosquitoes) corroborated the existing hypothesis of Indian An. minimus falling under the earlier reported mitochondrial lineage B.  相似文献   

7.
Background: The patterns of primary liver cancer incidence and survival are not known for detailed ethnic groups within the UK. Methods: Data on patients resident in England diagnosed with primary liver cancer (ICD-10 C22) between 2001 and 2007 were extracted from the National Cancer Data Repository. Age-standardised incidence rate ratios (IRRs) were calculated for different ethnic groups separately for males and females, using the White ethnic groups as baselines. Overall survival was analysed using Cox regression, adjusting sequentially for age, socioeconomic deprivation and co-morbidity. Results: Ethnicity data were available for 75% (13,139/17,458) of primary liver cancer patients. Compared with the White male baseline, Chinese males had the highest IRR. Black African, Bangladeshi, Pakistani and Indian men also had statistically significant high IRRs. Black Caribbean men had a marginally elevated incidence rate compared with White men. In comparison with White women, Pakistani women had the highest IRR. Bangladeshi, Chinese, Black African and Indian women also had high IRRs. As observed in men, Black Caribbean women had an incidence rate closer to that of White women. Pakistani men and women, Black African women and Chinese men had statistically significantly better survival compared with their White counterparts. Conclusion: The variation found in the incidence of primary liver cancer, could be due to established risk factors such as hepatitis B and C infection being more prevalent among certain ethnic groups. Country of birth, age at migration and length of stay in England are likely to be important factors in this disease, and future research should examine these where possible.  相似文献   

8.
Very little is known about the genes and mechanisms affecting skin lightening in Asian populations. In this study, two coding SNPs, c.G1129A (R163Q) at the MC1R (melanocortin 1 receptor) gene and c.A1962G (H615R) at the OCA2 (oculocutaneous albinism type II) gene, were investigated in a total of 1,809 individuals in 16 populations from various areas. The Q163 and R615 alleles prevailed almost exclusively in East and Southeast Asian populations. Wright’s F ST was 0.445 for R163Q and 0.385 for H615R among the 16 populations. The frequency of the Q163 allele was higher in Northeast Asians than in Southeast Asians. The frequency of the R615 allele was highest in South China and unlikely to be associated with levels of ultraviolet radiation. This allele may be a good marker to study the genetic affinity among East Asians because of its restricted distribution and marked difference in allele frequency.  相似文献   

9.
South Asia harbors one of the highest levels genetic diversity in Eurasia, which could be interpreted as a result of its long-term large effective population size and of admixture during its complex demographic history. In contrast to Pakistani populations, populations of Indian origin have been underrepresented in previous genomic scans of positive selection and population structure. Here we report data for more than 600,000 SNP markers genotyped in 142 samples from 30 ethnic groups in India. Combining our results with other available genome-wide data, we show that Indian populations are characterized by two major ancestry components, one of which is spread at comparable frequency and haplotype diversity in populations of South and West Asia and the Caucasus. The second component is more restricted to South Asia and accounts for more than 50% of the ancestry in Indian populations. Haplotype diversity associated with these South Asian ancestry components is significantly higher than that of the components dominating the West Eurasian ancestry palette. Modeling of the observed haplotype diversities suggests that both Indian ancestry components are older than the purported Indo-Aryan invasion 3,500 YBP. Consistent with the results of pairwise genetic distances among world regions, Indians share more ancestry signals with West than with East Eurasians. However, compared to Pakistani populations, a higher proportion of their genes show regionally specific signals of high haplotype homozygosity. Among such candidates of positive selection in India are MSTN and DOK5, both of which have potential implications in lipid metabolism and the etiology of type 2 diabetes.  相似文献   

10.
Hair morphology is a highly divergent phenotype among human populations. We recently reported that a nonsynonymous SNP in the ectodysplasin A receptor (EDAR 1540T/C) is associated with head hair fiber thickness in an ethnic group in Thailand (Thai-Mai) and an Indonesian population. However, these Southeast Asian populations are genetically and geographically close, and thus the genetic contribution of EDAR to hair morphological variation in the other Asian populations has remained unclear. In this study, we examined the association of 1540T/C with hair morphology in a Japanese population (Northeast Asian). As observed in our previous study, 1540T/C showed a significant association with hair cross-sectional area (P = 2.7 × 10−6) in Japanese. When all populations (Thai-Mai, Indonesian, and Japanese) were combined, the association of 1540T/C was stronger (P = 3.8 × 10−10) than those of age, sex, and population. These results indicate that EDAR is the genetic determinant of hair thickness as well as a strong contributor to hair fiber thickness variation among Asian populations. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

11.
We have analyzed 105 autosomal polymorphic short tandem repeat (STR) loci for nine East and South-eastern Asian populations (two Japanese, five Han Chinese, Thai, and Burmese populations) and a Caucasian population using a multiplex PCR typing system. All the STR loci are genomewide tetranucleotide repeat markers of which the total number of observed alleles and the observed heterozygosity were 756 and 0.743, respectively, for Japanese populations. Phylogenetic analysis for these allele frequency data suggested that the Japanese populations are more closely related with southern Chinese populations than central and/or northern ones. STRUCTURE program analysis revealed the almost clearly divided and accountable population structure at K=2–6, that the two Japanese populations always formed one group separated from the other populations and never belong to different groups at K≥3. Furthermore, our new allele frequency data for 91 loci were analyzed with those for 52 worldwide populations published by previous studies. Phylogenetic and multidimensional scaling (MDS) analyses indicated that Asian populations with large population size (six Han Chinese, three Japanese, two Southeast Asia) formed one distinct cluster and are closer to each other than other ethnic minorities in east and Southeast Asia. This pattern may be the caviar of comparing populations with greatly differing population sizes when STR loci were analyzed.  相似文献   

12.
GLUT is the major glucose transporter in mammalian cells. Single nucleotide polymorphisms (SNP) at GLUT1 promoter and regulatory regions have been associated to the risk of developing nephropathy in different type 1 and type 2 diabetic populations. It has been demonstrated that differences in allelic and genotypic frequencies of GLUT1 gene (SLC2A1) polymorphisms occur among different populations. Therefore, ethnic differences in distribution of GLUT1 gene polymorphisms may be an important factor in determining gene-disease association. In this study, we investigated the XbaIG > T and HaeIIIT > C polymorphisms in six different Brazilian populations: 102 individuals from Salvador population (Northern Brazil), 56 European descendants from Joinville (South Brazil), 85 Indians from Tiryió tribe (North Brazil) and 127 samples from Southern Brazil: 44 from European descendants, 42 from African descendants and 41 from Japanese descendants. Genotype frequencies from both sites did not differ significantly from those expected under the Hardy–Weinberg equilibrium. We verified that the allele frequencies of both polymorphisms were heterogeneous in these six Brazilian ethnic groups.  相似文献   

13.
Northeast India, the only region which currently forms a land bridge between the Indian subcontinent and Southeast Asia, has been proposed as an important corridor for the initial peopling of East Asia. Given that the Austro-Asiatic linguistic family is considered to be the oldest and spoken by certain tribes in India, Northeast India and entire Southeast Asia, we expect that populations of this family from Northeast India should provide the signatures of genetic link between Indian and Southeast Asian populations. In order to test this hypothesis, we analyzed mtDNA and Y-Chromosome SNP and STR data of the eight groups of the Austro-Asiatic Khasi from Northeast India and the neighboring Garo and compared with that of other relevant Asian populations. The results suggest that the Austro-Asiatic Khasi tribes of Northeast India represent a genetic continuity between the populations of South and Southeast Asia, thereby advocating that northeast India could have been a major corridor for the movement of populations from India to East/Southeast Asia.  相似文献   

14.
Effective counselling and management of retinoblastoma families using genetic information is presently practised in many parts of the world. We studied histopathological, chromosomal and molecular-genetic data of two retinoblastoma patients from India. The two patients, one with bilateral and the other with unilateral retinoblastoma, underwent complete ophthalmic examination, cytogenetic study, retinoblastoma gene (RB1) mutational analysis andRB1 promoter region methylation screening. In the bilateral retinoblastoma patient deletion of chromosome region 13q14 in peripheral blood lymphocytes and a hemizygous novel 8-bp deletion in exon 4 ofRB1 in tumour sample were observed. In the unilaterally affected patient CGA to TGA transition protein truncation mutations were observed in exons 8 and 14 ofRB1.  相似文献   

15.
We investigated phylogeography of Larix sukaczewii and Larix sibirica using nucleotide variation at three following nuclear gene regions: 5.8 S rDNA including two internal transcribed spacers (ITS), cinnamyl alcohol dehydrogenase (CAD), and phytochrome-O (PHYO). We also included sequences of the 4-coumarate: coenzyme A ligase (4CL) gene region obtained in our recent study. CAD and PHYO showed very low nucleotide variation, but ITS and 4CL had levels of variation similar to those reported for other conifers. Pleistocene refugia have been hypothesized to exist in the Southern Urals and South Central Siberia, where four out of nine of the investigated populations occur. We found moderate to high levels of population differentiation (F ST  = 0.115 – 0.531) in some pairwise comparisons suggesting limited gene flow and independent evolution of some refugial populations. In L. sukaczewii, low levels of differentiation were found among populations from areas glaciated during the Pleistocene, indicating their recent origin. Our results also suggest these populations were created by migrants from multiple, genetically distinct refugia. Furthermore, some haplotypes observed in populations from previously glaciated areas were not found in putative refugial populations, suggesting these populations might have contributed little to the extant populations created after the Last Glacial Maximum. Some authors regard L. sukaczewii and L. sibirica as a single species, while others consider them as separate species. The observed conspicuous differences in haplotype composition and distribution between L. sukaczewii and L. sibirica, together with high values of F ST between populations of the two species, appear to support the latter classification. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Ismael A. Khatab and Kariyawasam K.G.U. Hemamali contributed equally to this work.  相似文献   

16.
Summary We have used DNA probes for the human insulin gene and apolipoprotein C-II (apo C-II) gene to determine the extent of allelic variation in different ethnic groups. The distribution of an apo C-II DNA polymorphism revealed by the restriction endonuclease Taq I showed no significant variation amongst racial groups; in contrast, an insulin gene-related DNA polymorphism showed marked variability. In Japanese, Chinese, and Asian Indian groups there was an increased frequency of homozygosity for the class 1 allele compared to Caucasian groups (P<0.001, P<0.01, and P<0.05, respectively). In Caucasian, Japanese, Chinese, and Asian Indian groups no class 2 allele was observed; but in the Negroid populations (African and West Indian) the class 2 allele frequencies were 0.23 and 0.25 respectively. Possible reasons for this variation in allele distribution are considered in relation to disease associations.  相似文献   

17.
ObjectiveTo compare coronary risk factors and disease prevalence among Indians, Pakistanis, and Bangladeshis, and in all South Asians (these three groups together) with Europeans.DesignCross sectional survey.SettingNewcastle upon Tyne.Participants259 Indian, 305 Pakistani, 120 Bangladeshi, and 825 European men and women aged 25-74 years.ResultsThere were differences in social and economic circumstances, lifestyles, anthropometric measures and disease both between Indians, Pakistanis, and Bangladeshis and between all South Asians and Europeans. Bangladeshis and Pakistanis were the poorest groups. For most risk factors, the Bangladeshis (particularly men) fared the worst: smoking was most common (57%) in that group, and Bangladeshis had the highest concentrations of triglycerides (2.04 mmol/l) and fasting blood glucose (6.6 mmol/l) and the lowest concentration of high density lipoprotein cholesterol (0.97 mmol/l). Blood pressure, however, was lowest in Bangladeshis. Bangladeshis were the shortest (men 164 cm tall v 170 cm for Indians and 174 cm for Europeans). A higher proportion of Pakistani and Bangladeshi men had diabetes (22.4% and 26.6% respectively) than Indians (15.2%). Comparisons of all South Asians with Europeans hid some important differences, but South Asians were still disadvantaged in a wide range of risk factors. Findings in women were similar.ConclusionRisk of coronary heart disease is not uniform among South Asians, and there are important differences between Indians, Pakistanis, and Bangladeshis for many coronary risk factors. The belief that, except for insulin resistance, South Asians have lower levels of coronary risk factors than Europeans is incorrect, and may have arisen from combining ethnic subgroups and examining a narrow range of factors.

Key messages

  • South Asians have more coronary heart disease than Europeans despite apparently lower levels of risk factors
  • This study shows that Indians, Pakistanis and Bangladeshis differ in a wide range of coronary risk factors and combining their data is misleading
  • Among South Asians, Indians were least and Bangladeshis most disadvantaged in a range of coronary risk factors. South Asians were disadvantaged in comparison with Europeans
  • Future research and prevention strategies for coronary heart disease in South Asians should acknowledge a broad range of risk factors, the heterogeneity of these populations, linguistic and cultural needs, and environmental factors
  相似文献   

18.
In a survey of all notifications of tuberculosis in England and Wales for the first six months of 1983 56% of the 3002 newly notified patients who had not been treated before were of white and 37% were of Indian subcontinent (Indian, Pakistani, or Bangladeshi) ethnic origin, findings similar to those of a survey in 1978-9. In the four and a quarter years between the surveys the number of patients notified had declined by 26%, the decline being 28% among those of white and 23% among those of Indian subcontinent ethnic origin. The white patients were on average older than the patients of Indian subcontinent ethnic origin, and a higher proportion of them had respiratory disease (82% compared with 66%). The pulmonary lesions were on average larger and more often bacteriologically positive in the white patients. There were considerable differences between the ethnic groups in the estimated yearly rates of notifications per 100 000 population in England in 1983. The highest rates occurred in the Indian (178) and the Pakistani and Bangladeshi (169) populations and were roughly 25 times the rate in the white population (6 X 9). In the Indian subcontinent ethnic groups the highest rates occurred among those who had arrived in the United Kingdom within the previous five years.  相似文献   

19.
Anthropological and sociological literature points to the importance of religion as a basis for understanding the diverse nature of Britain's South Asian population. Using a rare quantitative source, the 1994 National Survey of Ethnic Minorities, and against a backdrop of relative neglect by quantitative social scientists, this article considers the religious dimension to observed differences in economic activity among South Asians. The analysis reports substantial differences between religious sub-groups (by age and sex) across a range of key measures, including: differences in the proportion who are economically active; differences in the proportion of the economically active who successfully gain employment; among the employed, differences in the type of jobs held and in reported income. The analysis suggests a more complex picture than the Muslim/non-Muslim dichotomy often inferred from analysis using conventional ethnic group classifications, with notable differences between Indian Sikhs and Hindus, and between Indian Muslims and Pakistani and Bangladeshi Muslims.  相似文献   

20.
Selection and genetic drift can create genetic differences between populations. Cytokines and chemokines play an important role in both hematopoietic development and the inflammatory response. We compared the genotype frequencies of 45 SNPs in 30 cytokine and chemokine genes in two healthy Chinese populations and one Caucasian population. Several SNPs in IL4 had substantial genetic differentiation between the Chinese and Caucasian populations (F ST ~0.40), and displayed a strikingly different haplotype distribution. To further characterize common genetic variation in worldwide populations at the IL4 locus, we genotyped 9 SNPs at the IL4 gene in the Human Diversity Panel’s (N = 1056) individuals from 52 world geographic regions. We observed low haplotype diversity, yet strikingly different haplotype frequencies between non-African populations, which may indicate different selective pressures on the IL4 gene in different parts of the world. SNPs in CSF2, IL6, IL10, CTLA4, and CX3CR1 showed moderate genetic differentiation between the Chinese and Caucasian populations (0.15 < F ST < 0.25). These results suggest that there is substantial genetic diversity in immune genes and exploration of SNP associations with immune-related diseases that vary in incidence across these two populations may be warranted.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号