Project description:Sakha M-bM-^@M-^S an area connecting South and Northeast Siberia M-bM-^@M-^S is significant for understanding the history of peopling of Northeast Eurasia and the Americas. Previous studies have shown a genetic contiguity between Siberia and East Asia and the key role of South Siberia in the colonization of Siberia. We report the results of a high-resolution phylogenetic analysis of 701 mtDNAs and 318 Y chromosomes from five native populations of Sakha (Yakuts, Evenks, Evens, Yukaghirs and Dolgans) and of the analysis of more than 500,000 autosomal SNPs of 758 individuals from 55 populations, including 40 previously unpublished samples from Siberia. Phylogenetically terminal clades of East Asian mtDNA haplogroups C and D and Y-chromosome haplogroups N1c, N1b and C3, constituting the core of the gene pool of the native populations from Sakha, connect Sakha and South Siberia. Analysis of autosomal SNP data confirms the genetic continuity between Sakha and South Siberia. Maternal lineages D5a2a2, C4a1c, C4a2, C5b1b and the Yakut-specific STR sub-clade of Y-chromosome haplogroup N1c can be linked to a migration of Yakut ancestors, while the paternal lineage C3c was most likely carried to Sakha by the expansion of the Tungusic people. MtDNA haplogroups Z1a1b and Z1a3, present in Yukaghirs, Evens and Dolgans, show traces of different and probably more ancient migration(s). Analysis of both haploid loci and autosomal SNP data revealed only minor genetic components shared between Sakha and the extreme Northeast Siberia. Although the major part of West Eurasian maternal and paternal lineages in Sakha could originate from recent admixture with East Europeans, mtDNA haplogroups H8, H20a and HV1a1a, as well as Y-chromosome haplogroup J, more probably reflect an ancient gene flow from West Eurasia through Central Asia and South Siberia. Our high-resolution phylogenetic dissection of mtDNA and Y-chromosome haplogroups as well as analysis of autosomal SNP data suggests that Sakha was colonized by repeated expansions from South Siberia with minor gene flow from the Lower Amur/Southern Okhotsk region and/or Kamchatka. The minor West Eurasian component in Sakha attests to both recent and ongoing admixture with East Europeans and an ancient gene flow from West Eurasia. 40 samples were analysed with the Illumina platform Human660W-Quad v1.0 and are described herein.
Project description:A microarray was developed to screen rodent samples for pathogens of zoonotic importance In the work described here, a homologue to Yersinia pestis was found in rodent samples after screening with the microarray A number of rodent samples from the UK and Canada were identified as carrying a homologue to a Yersinia pestis gene
Project description:Sakha – an area connecting South and Northeast Siberia – is significant for understanding the history of peopling of Northeast Eurasia and the Americas. Previous studies have shown a genetic contiguity between Siberia and East Asia and the key role of South Siberia in the colonization of Siberia. We report the results of a high-resolution phylogenetic analysis of 701 mtDNAs and 318 Y chromosomes from five native populations of Sakha (Yakuts, Evenks, Evens, Yukaghirs and Dolgans) and of the analysis of more than 500,000 autosomal SNPs of 758 individuals from 55 populations, including 40 previously unpublished samples from Siberia. Phylogenetically terminal clades of East Asian mtDNA haplogroups C and D and Y-chromosome haplogroups N1c, N1b and C3, constituting the core of the gene pool of the native populations from Sakha, connect Sakha and South Siberia. Analysis of autosomal SNP data confirms the genetic continuity between Sakha and South Siberia. Maternal lineages D5a2a2, C4a1c, C4a2, C5b1b and the Yakut-specific STR sub-clade of Y-chromosome haplogroup N1c can be linked to a migration of Yakut ancestors, while the paternal lineage C3c was most likely carried to Sakha by the expansion of the Tungusic people. MtDNA haplogroups Z1a1b and Z1a3, present in Yukaghirs, Evens and Dolgans, show traces of different and probably more ancient migration(s). Analysis of both haploid loci and autosomal SNP data revealed only minor genetic components shared between Sakha and the extreme Northeast Siberia. Although the major part of West Eurasian maternal and paternal lineages in Sakha could originate from recent admixture with East Europeans, mtDNA haplogroups H8, H20a and HV1a1a, as well as Y-chromosome haplogroup J, more probably reflect an ancient gene flow from West Eurasia through Central Asia and South Siberia. Our high-resolution phylogenetic dissection of mtDNA and Y-chromosome haplogroups as well as analysis of autosomal SNP data suggests that Sakha was colonized by repeated expansions from South Siberia with minor gene flow from the Lower Amur/Southern Okhotsk region and/or Kamchatka. The minor West Eurasian component in Sakha attests to both recent and ongoing admixture with East Europeans and an ancient gene flow from West Eurasia.
Project description:The etiologic agent of bubonic plague, Yersinia pestis, senses cell density-dependent chemical signals to synchronize transcription between cells of the population in a process named quorum sensing. Though the closely related enteric pathogen Y. pseudotuberculosis uses quorum sensing system to regulate motility, the role of YpeIR quorum sensing in Y. pestis has been unclear. YpeIR is one of the AHL quorum sensing system in Y. pestis. In this study we performed transcriptional profiling experiments to identify Y. pestis YpeIR quorum sensing regulated functions at 37°C.
Project description:A microarray was developed to screen rodent samples for pathogens of zoonotic importance In the work described here, a homologue to Yersinia pestis was found in rodent samples after screening with the microarray
Project description:Affymetrix single nucleotide polymorphism (SNP) array data were collected to study genome-wide patterns of genomic variation across a broad geographical range of Island Southeast Asian populations. This region has experienced an extremely complex admixture history. Initially settled ~50,000 years ago, Island Southeast Asia has since been the recipient of multiple waves of population movements, most recently by Austronesian-speaking groups ultimately from Neolithic mainland Asia and later arrivals during the historic era from India and the Middle East. We have genotyped SNPs in ~500 individuals from 30 populations spanning this entire geographical region, from communities close to mainland Asia through to New Guinea. Particular attention has been paid to genomic data that are informative for population history, including the role of recent arrivals during the historic era and admixture with archaic hominins.
Project description:Quorum sensing is a cell to cell communication process that involves chemical signaling. Yersinia pestis, the agent of plague, has two functional AHL quorum sensing systems Ysp and Ype. For several reasons, it was not clear what effect AHL pathways have on virulence gene expression and survival in the two different hosts, flea and human. To investigate to what effect AHL quorum sensing has on gene expression, we conducted microarray studies comparing Yersinia pestis CO92 (∆pgm) to a double AHL mutant strain (∆pgm ΔypeIR) at 30°C.
Project description:Quorum sensing is a cell to cell communication process that involves chemical signaling. Yersinia pestis, the agent of plague, has two functional AHL quorum sensing systems Ysp and Ype. For several reasons, it was not clear what effect AHL pathways have on virulence gene expression and survival in the two different hosts, flea and human. To investigate to what effect AHL quorum sensing has on gene expression, we conducted microarray studies comparing Yersinia pestis CO92 (∆pgm) to a double AHL mutant strain (∆pgm ΔypeIR ΔyspIR) at 37°C.