Stephen J. O'Brien

Bio: Stephen J. O'Brien is an academic researcher from Saint Petersburg State University of Information Technologies, Mechanics and Optics. The author has contributed to research in topics: Population & Gene. The author has an hindex of 153, co-authored 1062 publications receiving 93025 citations. Previous affiliations of Stephen J. O'Brien include University College Cork & QIMR Berghofer Medical Research Institute.

Paternity assignment of giant panda by microsatellite genotyping

Abstract: We used genotype data across 18 microsatellite loci to establish the paternity of giant panda cubs at the Chengdu Zoo and the Chengdu Research Base of Giant Panda Breeding. The results demonstrate that the combined exclusion probability using these 18 microsatellite loci is 0.999921 while confidence is 95 % when the mother is known; if mother is unknown then the exclusion probability is 0.994109, but the confidence of this is less than 80%. Since the mother-offspring relationship is known in captive populations, the results could resolve unknown paternities in the Chengdu ex situ populations. However, to establish accurately the genetic relationships of wild giant pandas,more microsatellite loci may be required.

Application of Machine Learning Algorithms to Predict Clinically Meaningful Improvement After Arthroscopic Anterior Cruciate Ligament Reconstruction.

Abstract: Background:Understanding specific risk profiles for each patient and their propensity to experience clinically meaningful improvement after anterior cruciate ligament reconstruction (ACLR) is impor...

The Prevalence and Politics of HIV/AIDS in Zimbabwe: Examining the Ideological, Political and Historical Factors Behind the ‘Decline’

Abstract: The reported reduction in the prevalence level of the Human Immunodeficiency Virus (HIV) in Zimbabwe has been represented as one of the most significant and rapid declines within any population since the epidemic emerged as a public health issue. This paper explains how this development has been reported, challenged and eventually owned by many of the diverse stakeholders who constitute Zimbabwe's overall AIDS response. The Zimbabwean government has claimed that the decline was brought about due to its own efforts and resources. However, while the country has received considerably less AIDS funding than its neighbours, external donations still account for the vast bulk of AIDS spending in Zimbabwe. In addition, instead of collapsing, as some predicted, the Zimbabwean state can also claim that it has presided over increased availability of antiretroviral therapy. In this paper we examine how various internal and external stakeholders deployed strategic explanations in an attempt to take credit for ‘the dec...

Proceedings in Phylogeography and Genetic Ancestry of Tigers (Panthera tigris) in China and Across Their Range

Abstract: Of eight traditionally classified subspecies of the tiger Panthera tigris three have recently gone extinct and poaching, habitat loss and fragmentation continue to threaten its survival. China historically harbors four of the existing subspecies and thus has high conservation priority, yet their status, both in the wild and captivity, remains highly uncertain. A recent molecular survey (Luo et al, 2004) of 134 "voucher specimens" (taken from tigers of verified wild ancestry and geographic origin), from across the full range including China, examined three different types of molecular markers; four kilobase-pairs of mitochondrial DNA, 30 nuclear microsatellite loci and the nuclear major histocompatibility complex class II DRB gene; to elucidate the genetic structure of tiger populations. The data revealed relatively low genetic variation but nonetheless significant population subdivisions, suggesting six rather than five living subspecies: (1) Amur tiger P. t. altaica, (2) South China tiger P. t. amoyensis, (3) a refined Indochinese tiger P. t. corbetti, (4) a new subspecies Malayan tiger P. t. jacksoni, named after the tiger conservationist Peter Jackson, (5) Sumatran tiger P. t. sumatrae, and (6) Bengal tiger P. t. tigris. Reduced gene flow and genetic drift in isolated populations since the last genetic diminution about 72 000-108 000 years ago, as well as the recent anthropogenic range contraction, is likely to have caused these partitions. In particular, the proposed South China tiger lineage is tentative due to limited sampling. It is apparent that current captive South China tigers inherit at least two genetic lineages: one that is unique and distinct from the other subspecies and a second indistinguishable from the northern Indochinese tigers. An explicit genetic assessment of the captive tigers in China is urgently needed to validate the uniqueness or non-uniqueness of the South China tiger, or indeed the survival of P. t. amoyensis.

Initial sequencing and analysis of the human genome.

Abstract: The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Genome-wide association study of 14,000 cases of seven common diseases and 3,000 shared controls

Abstract: There is increasing evidence that genome-wide association ( GWA) studies represent a powerful approach to the identification of genes involved in common human diseases. We describe a joint GWA study ( using the Affymetrix GeneChip 500K Mapping Array Set) undertaken in the British population, which has examined similar to 2,000 individuals for each of 7 major diseases and a shared set of similar to 3,000 controls. Case-control comparisons identified 24 independent association signals at P < 5 X 10(-7): 1 in bipolar disorder, 1 in coronary artery disease, 9 in Crohn's disease, 3 in rheumatoid arthritis, 7 in type 1 diabetes and 3 in type 2 diabetes. On the basis of prior findings and replication studies thus-far completed, almost all of these signals reflect genuine susceptibility effects. We observed association at many previously identified loci, and found compelling evidence that some loci confer risk for more than one of the diseases studied. Across all diseases, we identified a large number of further signals ( including 58 loci with single-point P values between 10(-5) and 5 X 10(-7)) likely to yield additional susceptibility loci. The importance of appropriately large samples was confirmed by the modest effect sizes observed at most loci identified. This study thus represents a thorough validation of the GWA approach. It has also demonstrated that careful use of a shared control group represents a safe and effective approach to GWA analyses of multiple disease phenotypes; has generated a genome-wide genotype database for future studies of common diseases in the British population; and shown that, provided individuals with non-European ancestry are excluded, the extent of population stratification in the British population is generally modest. Our findings offer new avenues for exploring the pathophysiology of these important disorders. We anticipate that our data, results and software, which will be widely available to other investigators, will provide a powerful resource for human genetics research.