31 research outputs found
Phylogenetic analysis of mitochondrial DNA sequences reveals polyphyly in the goitred gazelle (Gazella subgutturosa)
No full text
Networks, strata and ageing: towards a compositional demography of vulnerability
No full textIn a recent commentary, Kreager (2011) has argued for the “strategic value of studying population composition” in order better to identify the units of population relevant for understanding vulnerability. Conventional approaches, relying on census and survey sources which model populations as homogenous, bounded and composed of discrete households, have failed to accomplish this. Drawing on ethnographic and demographic fieldwork in rural Indonesia, this paper attempts a contribution to ‘compositional demography’ by illustrating a methodology for identifying the subpopulations within a community which are relevant for understanding vulnerability in later life. Key differentials at the local level include the availability of children and socio-economic strata; combining these two dimensions begins to point to significant vulnerable subgroups but falls short of explaining outcomes in later life, because demographic and socio-economic characteristics are mediated by membership of wider networks. The paper therefore characterises a number of indicative and contrasting kinship networks in the study community in terms of their demographic success, marital alliances, land ownership and occupational identities, and examines how these networks have differentially aligned themselves with broader religious, economic and social shifts. Some networks are better able to exploit the opportunities that education or migration entail, others founder on fragmentation of assets, fecklessness and disharmony, and the loss of reputation that entails. It becomes possible to distinguish ascending and descending, locally-bound and translocalizing, and ‘traditional’ and ‘modernising’ networks. Once older people are located within these different kinds of networks, their treatment and differential vulnerability need no longer be modelled purely on their individual characteristics or immediate household or family contexts, but can be understood as the outcome of negotiations, manoeuvrings and sometimes failures of the networks to which they belong. The needs and priorities of elders themselves are rarely of central concern to key agents within the networks, a fact which underlines the limitations of treating ‘the older population’ in isolation. In short, the paper makes an argument for treating networks as the population components of relevance for understanding socio-demographic processes, including population ageing. Identifying and modelling networks raises important conceptual and methodological challenges, but in virtue of being multi-generational, reproductive identities which encompass diversity and cut across strata and space, networks are socially meaningful and empirically grounded population units within which to understand human behaviour<br/
The genetic structure of the British populations and their surnames
No full textUntil large-scale ancient DNA studies of archaeological samples become practical, genetic studies of current human populations, with a few caveats, are a productive way to investigate past movements of peoples (Røyrvik 2010). Recent advances in techniques for typing and analysing thousands of genetic markers in large numbers of individuals offer exciting opportunities to investigate population structure at a fine geographic level. For example, investigating population structure between regions of the British Isles can shed light on the impact people from different parts of Europe had on Britain. These methods are a natural progression from earlier studies on a small number of genetic markers into the underlying genetic structure of Europe and the processes that are the likely causes. One of the earliest such informative studies was based on data from the human leukocyte antigen (HLA)region, a gene rich region, many of which are associated with the immune response. Menozzi et al. (1978) used a principle components analysis (PCA) approach to demonstrate that there was a genetic gradient from the Middle East to north-west Europe. This gradient suggested that there was a gradual migration of people, leading to a corresponding dilution of difference between the origin and extremity. This is likely to have started in the Middle East about 10,000 years ago, moving north-west at about 1 km a year, in parallel with agriculture, and reaching the UK about 5,000 years ago. When investigating smaller geographic area, a good example of hidden heterogeneity is ‘Little England beyond Wales’ (Watkin 1956; 1960). This is the region of south Pembrokeshire that is linguistically and toponymically different from the rest of the region, most likely due to settlement of Vikings in the 9th century AD(Loyn 1976) and/or Flemish farmers, settled by Henry I in the early 12th century (MacKintosh 1866). Watkin (1956; 1960) observed that there was a higher frequency of blood group ABOtype A in that region than amongst the Welsh in general. He thought that this was likely to be caused by Viking settlement because the Norwegians had a similar frequency of A. Contradicting this, a PCA analysis of Y chromosome data, that included samples from Haverfordwest, groups Haverfordwest with the rest of Wales and appears to rule out a Norse contribution, although this analysis is only of the male lineage (Capelli et al. 2003)
Mulberry harbour 1944-1994
No full textOverview of the construction of the caissons and the construction of the invasion port at Arromanches in Normandy, France. Includes interviews with the engineers involved
Two reciprocally monophyletic mtDNA lineages elucidate the taxonomic status of Mountain gazelles (<i>Gazella gazella</i>)
No full textMountain gazelles (Gazella gazella) rank among the most critically endangered mammals on the Arabian Peninsula. Past conservation efforts have been plagued by confusion about the phylogenetic relationship among various 'phenotypically discernable' populations, and even the question of species boundaries was far from being certain. This lack of knowledge has had a direct impact on conservation measures, especially ex situ breeding programmes, hampering the assignment of captive stocks to potential conservation units. Here, we provide a phylogenetic framework, based on the analysis of mtDNA sequences (360 bp cytochrome b and 213 bp Control Region) of 126 individuals collected from the wild throughout the Arabian Peninsula and from captive stocks. Our analyses revealed two reciprocally monophyletic genetic lineages within the presumed species Gazella gazella: one 'northern clade' on the Golan Heights (Israel/Syrian border) and one genetically diverse larger clade from the rest of the Arabian Peninsula including the Arava Valley (Negev, Israel). Applying the Strict Phylogenetic Species Concept (sensu Mishler & Theriot, 2000) allows assigning species status to these two major clades
Rare variant hypothesis for multifactorial inheritance: susceptibility to colorectal adenomas as a model.
No full textThe rare variant hypothesis postulates that genetic susceptibility to colorectal neoplasia within the general population is due to a number of low frequency variants in a variety of different genes. Each variant confers a moderate, but detectable, increase in relative risk of developing the disease. Recent evidence suggests that a quarter of patients with multiple adenomatous polyps are due to rare but functionally important variants in just five genes
Is Dupuytren’s disease really a “disease of the Vikings”?
No full textIt has been suggested that Dupuytren’s Disease has an origin in Norse countries. We harnessed data from a genome-wide association study of Dupuytren’s Disease and the People of the British Isles study to determine evidence for a Norse origin of Dupuytren’s Disease. We computed Wright’s Fixation Index between Orkney (Norse ancestry), Wales (ancient British) and South East England (Anglo-Saxons); compared mean Wright’s Fixation Index in cases versus controls; used permutation to determine any excess of Norse inheritance in disease associated variants; constructed a genetic risk score for Dupuytren’s Disease and applied this to the People of the British Isles dataset to look for systematic differences between counties with known high and low levels of Norse ancestry. Finally, chromosome painting was used to see whether Dupuytren’s Disease associated single nucleotide polymorphisms are geographically structured. In all analyses, no evidence was found for an excess of Norse ancestry in Dupuytren’s Disease. We conclude that there is no genetic evidence for a “Viking origin of Dupuytren’s Disease”
