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Variation within the gene for the proinflammatory cytokine interleukin (IL)-18 has been associated with inter-individual differences in levels of free protein and disease risk. We investigated the frequency of function-associated IL18 gene haplotypes in an extensive sample (n=2357) of African populations from across the continent. A previously identified five tagging SNP (single-nucleotide polymorphism) haplotype (here designated hGTATA), known to be associated with lower levels of IL-18, was observed at a frequency of 27% in a British population of recent European ancestry, but was found at low frequency (

The expansion of the Bantu-speaking people (EBSP) during the past 3000–5000 years is an event of great importance in the history of humanity. Anthropology, archaeology, linguistics and, in recent decades, genetics have been used to elucidate some of the events and processes involved. Although it is generally accepted that the EBSP has its origin in the so-called Bantu Homeland situated in the area of the border between Nigeria and the Grassfields of Cameroon, and that it followed both western and eastern routes, much less is known about the number and dates of those expansions, if more than one. Mitochondrial, Y-chromosome and autosomal DNA analyses have been carried out in attempts to understand the demographic events that have taken place. There is an increasing evidence that the expansion was a more complex process than originally thought and that neither a single demographic event nor an early split between western and eastern groups occurred. In this study, we analysed unique event polymorphism and short tandem repeat variation in non-recombining Y-chromosome haplogroups contained within the E1b1a haplogroup, which is exclusive to individuals of recent African ancestry, in a large, geographically widely distributed, set of sub-Saharan Africans (groups=43, n=2757), all of whom, except one Nilo-Saharan-speaking group, spoke a Niger-Congo language and most a Bantu tongue. Analysis of diversity and rough estimates of times to the most recent common ancestors of haplogroups provide evidence of multiple expansions along eastern and western routes and a late, exclusively eastern route, expansion.

The Alps are one of the most significant geographical barriers in Europe and several isolated Swiss and Italian valleys retain the distinctive Ladin and Romansch languages, alongside the modern majority of Italian and German languages. Linguistically, Ladin belongs to the Romance languages, but some studies on mitochondrial DNA (mtDNA) variation have suggested a major Middle Eastern component to their genealogical origin. Furthermore, an observed high degree of within-population diversity has been interpreted as reflecting long-standing differentiation from other European populations and the absence of a major bottleneck in Ladin population history. To explore these issues further, we examined Y chromosome and mtDNA variation in two samples of Ladin speakers, two samples of German speakers and one sample of metropolitan Italian speakers. Our results (1) indicate reduced diversity in the Ladin-speaking and isolated German-speaking populations when compared to a sample of metropolitan Italian speakers, (2) fail to identify haplotypes that are rare in other European populations that other researchers have identified, and (3) indicate different Middle Eastern components to Ladin ancestry in different localities. These new results, in combination with Bayesian estimation of demographic parameters of interest (population size, population growth rate, and Palaeolithic/Neolithic admixture proportions) and phylogeographic analysis, suggest that the Ladin groups under study are small genetically isolated populations (subject to strong genetic drift), having a predominantly European ancestry, and in one locality, may have a greater Palaeolithic component to that ancestry than their neighbours.