1,721,122 research outputs found
Health in the Himalayas and the Himalayan homelands
No full textIn September 2012, the eminent Estonian population geneticist Toomas Kivisild convened and hosted a gathering at the University of Cambridge entitled High Altitude and Cold: Adaptation to Extremes. This joyous event was billed as 'a conference to discuss the latest scientific results on human physiological and genetic adaptation to high altitudes and cold environments'. Memorable speakers included Hugh Montgomery, Andrew J. Murray, Miroslava Derenko, Cynthia Beal, Maanasa Raghavan, Dennis O'Rourke, Gianpiero Cavalleri, Anna di Rienzo and Bill Amos. In addition to population geneticists and physiologists, Toomas Kivisild invited to Cambridge a single linguist, who happened to find genetics symposia more enlightening and often more full of ebullience than linguistic gatherings. Just how damaging life at high altitudes can be for people who are genetically ill-equipped to cope with cold high-altitude environments was demonstrated by Andrew J. Murray of Cambridge, who reported on an expedition called Extreme Everest. This scientific expedition aimed to study the metabolic response of heart and muscle tissue to high-altitude hypoxia. It appears that a failing heart is somehow unable to oxidise fatty acids whilst in a state of dilated cardiomyopathy. This inability has to do with hypoxia inducible factors (HIF) and metabolic regulation, with hypoxia inducible factor one-alpha (HIF-1α) accumulating in hypoxic tissues. Fortunately, in healthy individuals, heart impairment caused by high altitude can repair itself after, say, about six months. Most interesting is how this impairment plays out at the biochemical level within the cell
The study of human Y chromosome variation through ancient DNA
Full text linkHigh throughput sequencing methods have completely transformed the study of human Y chromosome variation by offering a genome-scale view on genetic variation retrieved from ancient human remains in context of a growing number of high coverage whole Y chromosome sequence data from living populations from across the world. The ancient Y chromosome sequences are providing us the first exciting glimpses into the past variation of male-specific compartment of the genome and the opportunity to evaluate models based on previously made inferences from patterns of genetic variation in living populations. Analyses of the ancient Y chromosome sequences are challenging not only because of issues generally related to ancient DNA work, such as DNA damage-induced mutations and low content of endogenous DNA in most human remains, but also because of specific properties of the Y chromosome, such as its highly repetitive nature and high homology with the X chromosome. Shotgun sequencing of uniquely mapping regions of the Y chromosomes to sufficiently high coverage is still challenging and costly in poorly preserved samples. To increase the coverage of specific target SNPs capture-based methods have been developed and used in recent years to generate Y chromosome sequence data from hundreds of prehistoric skeletal remains. Besides the prospects of testing directly as how much genetic change in a given time period has accompanied changes in material culture the sequencing of ancient Y chromosomes allows us also to better understand the rate at which mutations accumulate and get fixed over time. This review considers genome-scale evidence on ancient Y chromosome diversity that has recently started to accumulate in geographic areas favourable to DNA preservation. More specifically the review focuses on examples of regional continuity and change of the Y chromosome haplogroups in North Eurasia and in the New World
A general method for the statistical evaluation of typological distributions
No full textThe distribution of linguistic structures in the world is the joint product of universal principles, inheritance from ancestor languages, language contact, social structures, and random fluctuation. This paper proposes a method for evaluating the relative significance of each factor — and in particular, of universal principles — via regression modeling: statistical evidence for universal principles is found if the odds for families to have skewed responses (e.g. all or most members have postnominal relative clauses) as opposed to having an opposite response skewing or no skewing at all, is significantly higher for some condition (e.g. VO order) than for another condition, independently of other factors
Gene diversity among some endogamous population of Amravati District, Maharashtra, India.
Full text linkThe present work deals with the distribution of ABO, Rh and sickling alleles as markers to study the genetic structure and micro-demarcation among castes and tribal populations from the Amravati district of Maharashtra. Three loci namely, ABO, Rh and sickling were selected to measure the relative frequency of respective alleles in ten (10) endogamous populations inhabiting the Amravati District. The ABO locus was found to be less polymorphic when compared with other loci. On the other hand, Rh and sickling loci were found to be more polymorphic. Construction of a dendrogram using allele frequency data reveals an interesting relationship among the caste and tribe. An analysis shows three major clades comprising A, B and C. Clade A comprises Islamic Dawoodi Bohra and Hindu Gujrati. Clade B comprises the upper castes, Brahmin, Jain, Kashmiris and Kunbis, while Clade C shows Gonds and Katchhi. This study is a first attempt to provide a genetic landscape of castes and tribes inhabiting the Vidarbha region. The findings are discussed in light of the historical, anthropological and genetic data available for the studied group
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