Project description:Myanmar locates in the crossroads of South Asia, Southeast Asia, and East Asia, and is known for high culture diversity in different ethnic groups. It is considered to be important for understanding human evolutionary history and genetic diversity in East Eurasia. However, relatively few studies have examined the population structure and demographic history in Myanmar to date. In this study, we analyzed more than 220,000 genome-wide SNPs in 175 new samples of five ethnic groups from Myanmar and compared them with the published data. Our results showed that the Myanmar population is intricately substructured, with the main observed clusters corresponding roughly to western/northern highlanders (Chin, Naga, and Jingpo) and central/southern lowlanders (Bamar and Rakhine). The gene flow inferred from South Asia has a substantial influence (~11%) on the gene pool of central/southern lowlanders rather than western/northern highlanders. The genetic admixture is dated around 650 years ago. These findings suggest that the genome-wide variation in Myanmar was likely shaped by the linguistic, cultural, and historical changes.
2019-12-31 | GSE74100 | GEO
Project description:Amphibians and Reptiles of the Northern Karst Forests in Vietnam
Project description:We mapped DNA methylation in 580 animal species (535 vertebrates, 45 invertebrates), resulting in 2443 genome-scale, base-resolution DNA methylation profiles of primary tissue samples from various organs. Reference-genome independent analysis of this comprehensive dataset defined a “genomic code” of DNA methylation, which allowed us to predict global and locus-specific DNA methylation from the DNA sequence within and across species. This code appears broadly conserved throughout vertebrate evolution, with two major transitions – once in the first vertebrates and again with the emergence of reptiles. Beyond the central role of species-specific DNA sequence composition, our dataset identified the tissue type and the individual as two main sources of DNA methylation variability within species. Tissue type was the dominant factor in fish, birds, and mammals, while in invertebrates, reptiles, and amphibians both factors were similarly strong. Cross-species comparisons focusing on heart and liver tissues supported a highly conserved role of DNA methylation for tissue type and identity and cross-mapping based promoter methylation analysis revealed divergence at specific genes. In summary, this study establishes a large resource of vertebrate and invertebrate DNA methylomes, it showcases the power of reference-free epigenome analysis in species for which no reference genomes are available, and it contributes an epigenetic perspective to the study of vertebrate evolution.
Project description:Background. The Beijing family of Mycobacterium tuberculosis is dominant in countries in East Asia. Genomic polymorphisms are a source of diversity within the M.tuberculosis genome and may account for the variation of virulence among M.tuberculosis isolates. To date there are no studies that have examined the genomic composition of M.tuberculosis isolates from the high TB-burden country, Myanmar. Methodology/Principle findings. Twenty-two M.tuberculosis isolates from Myanmar were screened on whole-genome arrays containing genes from M.tuberculosis H37Rv, M.tuberculosis CDC1551 and M.bovis AF22197. Screening identified 198 deletions or extra regions in the clinical isolates compared to H37Rv. Twenty-two regions differentiated between Beijing and non-Beijing isolates and were verified by PCR on an additional 40 isolates. Six regions (Rv0071-0074 [RD105], Rv1572-1576c [RD149], Rv1585c-1587c[RD149], MT1798-Rv1755c [RD152], Rv1761c [RD152] and Rv0279c) were deleted in Beijing isolates, of which 4 (Rv1572-1576c, Rv1585c-1587c, MT1798-Rv1755c and Rv1761c) were variably deleted among ST42 isolates, indicating a closer relationship between the Beijing and ST42 lineages. The TbD1 region, Mb1582-Mb1583 was deleted in Beijing and ST42 isolates. One M.bovis gene of unknown function, Mb3184c was present in all isolates, except 11 of 13 ST42 isolates. The CDC1551 gene, MT1360 coding for a putative adenylate cyclase, was present in all Beijing and ST42 isolates (except 1). The pks15/1 gene, coding for a putative virulence factor, was intact in all Beijing and non-Beijing isolates, except in ST42 and ST53 isolates. Conclusion. This study describes previously unreported deletions/extra regions in Beijing and non-Beijing M.tuberculosis isolates. The modern and highly frequent ST42 lineage showed a closer relationship to the hypervirulent Beijing lineage than to the ancient non-Beijing lineages. The pks15/1 gene was disrupted only in modern non-Beijing isolates. This is the first report of an in-depth analysis on the genomic diversity of M.tuberculosis isolates from Myanmar. Data is also available from http://bugs.sgul.ac.uk/E-BUGS-66
2008-09-26 | E-BUGS-66 | biostudies-arrayexpress
Project description:Madagascar: Preserving a blueprint of Asteracaeae hyperendemism in a biodiversity hotspot