Project description:A 6,000-year-long genomic transect from the Bogotá Altiplano reveals multiple genetic shifts in the demographic history of Colombia
Project description:With the largest genomic dataset to date of Bantu-speaking populations, including newly generated data of modern-day and ancient DNA from previously unsampled regions in Africa, we shed fresh light on the expansion of peoples speaking Bantu languages that started ~4000 years ago in western Africa. We have generated whole-genome sequences from 12 Late Iron Age individuals. Our comprehensive genetic analysis of the expansion of people speaking Bantu languages reveals a complex history of serial founder events, variable levels of contact with local groups, and spread-over-spread events.
Project description:Core histone hyperacetylation, in particular of H4, is concentrated in the promoter-upstream regions of active genes and in certain cases is locuswide. Antibodies to hyperacetylated H4 were used to immunoprecipitate dinucleosomal chromatin derived from K562 human erythroleukemic cells by micrococcal nuclease digestion. The extracted DNA was made into a genomic library and was expected to contain sequences from genes active in K562 cells (an active, 'aDNA' library). Clones (180) were randomly selected from the library; 24 of 103 tested (23%) contained highly repeated sequences, as determined by their hybridization to total genomic DNA, and were not analyzed further. An additional 10 clones (6%) were shown to contain no insert DNA. The remaining 146 were sequenced and compared with the nucleic acid databases and in all six frames to the protein databases: Sixeen clones could be assigned to known genes, the majority of which (12) were tissue specific. All but 2 of these 16 corresponded to segments 5' of the coding sequences, as expected if H4 acetylation is concentrated at promoter regions. Thirty-three clones (23%) displayed high sequence identity to cDNAs in the expressed sequence tag database (dbEST). Northern blots and reverse transcription (RT)-PCR were used to determine the proportion of clones representing sequences expressed in K562 cells: Although only 1 of 34 tested clones showed a band in Northern hybridization, RT-PCR demonstrated that at least 12 of 40 tested clones (30%) were present in the mRNA population. Because a further 8 of these 40 clones were identified as gene fragments by database sequence comparisons, it follows that about half of this subset of 40 clones is derived from genes. The aDNA library is thus very gene rich and not skewed toward the most highly expressed sequences, as in mRNA libraries. The aDNA library is also rich in promoters and could be a valuable source of such sequences, particularly those that lack CpG islands or other features that allow their specific selection.
Project description:Investigation of whole genome gene expression AdnA in Pseudomonas fluorescens, an ortholog of FleQ in P. aeruginosa, regulates both motility and flagella-mediated attachment to various surfaces. A whole genome microarray determined the AdnA transcriptome by comparing the gene expression pattern of wild-type Pf0-1 to that of Pf0-2x (adnA-) in broth culture. In the absence of AdnA, expression of 92 genes was decreased, while 11 genes showed increased expression. Analysis of 16 of these genes fused to lacZ confirmed the microarray results. Several genes were further evaluated for their role in motility and biofilm formation. Two genes, Pfl01_1508 and Pfl01_1517, affected motility and had different effects on biofilm formation in Pf0-1. These two genes are predicted to encode proteins similar to the glycosyl transferases FgtA1 and FgtA2, which have been shown to be involved in virulence and motility in P. syringae. Three other genes, Pfl01_1516, Pfl01_1572, and Pfl01_1573, not previously associated with motility and biofilm formation in Pseudomonas had similar affects on biofilm formation in Pf0-1. Deletion of each of these genes led to different motility defects. Our data revealed an additional level of complexity in the control of flagella function beyond the core genes known to be required, and may yield insights into processes important for environmental persistence of P. fluorescens Pf0-1.