Project description:The genetic structure of some native Bolivians has been substantially influenced by admixture from Europeans, which we estimate to have occurred approximately 360 – 384 years ago. Consistent with historical accounts of male admixture, Y-chromosome haplogroups typical of Europeans were found in 39% of our Bolivian samples. No evidence of African admixture was found in native Bolivians. The Mesoamerican Totonacs have little evidence of European or African admixture. Our analysis indicates that some admixed Bolivians have Native American mtDNA and Y-chromosomes but harbor up to 30% European autosomal ancestry, demonstrating the need for autosomal markers to assess ancestry in admixed populations. From a dense genome-wide panel of 815,377 markers, we developed a set of 324 AIMs, specific for Native American ancestry. As few a 40-50 of these markers successfully predict New World ancestry in the ascertainment panel of Bolivians and Totonacs. The markers easily distinguish New World from Old World ancestry, even for populations more closely related to the Americas such as central and eastern Asians, and were effective for New World vs. Old World comparisons in five other geographically and culturally distinct populations of the Americas. SNPs demonstrating very high divergence between the two Native American populations and major Old World populations are found on haplotypes that are shared and occur at similar frequencies in other indigenous low-admixture American populations examined here (i.e. Pima, Maya, Colombian, Karitiana, and Surui). After excluding the possibility of recent relatedness, our results indicate that native Bolivians and Totonacs share ancestry with other American populations through a substantial contribution from a common founding population, population bottlenecks, and possible natural selection on functional variation.
Project description:Background: Drug resistance is a major problem in leishmaniasis chemotherapy. RNA expression profiling using DNA microarrays is a suitable approach to study simultaneous events leading to a drug-resistance phenotype. Genomic analysis has been performed primarily with Old World Leishmania species and here we investigate molecular alterations in antimony resistance in the New World species L. amazonensis. Methods/Principal Findings: We selected populations of L. amazonensis for resistance to antimony by step-wise drug pressure. Gene expression of highly resistant mutants was studied using DNA microarrays. RNA expression profiling of antimony-resistant L. amazonensis revealed the overexpression of genes involved in drug resistance including the ABC transporter MRPA and several genes related to thiol metabolism. The MRPA overexpression was validated by quantitative real-time PCR and further analysis revealed that this increased expression was correlated to gene amplification as part of extrachromosomal linear amplicons in some mutants and as part of supernumerary chromosomes in other mutants. The expression of several other genes encoding hypothetical proteins but also nucleobase and glucose transporter encoding genes were found to be modulated. Conclusions/Significance: Mechanisms classically found in Old World antimony resistant Leishmania were also highlighted in New World antimony-resistant L. amazonensis. These studies were useful to the identification of resistance molecular markers.
Project description:We compared gene expression patterns between the occipital cortex tissues of four male and four female individuals in three species: an ape (human, Homo sapiens), an Old World monkey (macaque; Macaca fascicularis), and a New World monkey (marmoset; Callithrix jacchus). To do so, we hybridized cDNA from each sample (n = 24) to a human cDNA microarray that contains 46,128 probes. (Human 46k cDNA, http://www.biotech.kth.se/molbio/microarray/). We used a loop hybridization study design restricted to within-species comparisons only, in which we co-hybridized on each slide samples from the opposite sex.
Project description:Vitrification is replacing slow freezing as the most popular method for human embryo cryopreservation in clinics world-wide. Several studies demonstrated that cryopreservation alters gene expression of mammalian embryos, but none of them analysed what happen with those embryos that get implanted and follow with the gestation. The aim of this study was to evaluate the effect of vitrification technique on rabbit embryonic and fetal development by performing a transcriptomic analysis of 6 day old embryos and 14 days old fetal placentas.
2013-09-26 | GSE51208 | GEO
Project description:Comparison of complete mitochondrial DNA sequences of Aphis craccivora from old and new world
| PRJNA375106 | ENA
Project description:Cyanobacteria diversity in limestone monuments in Old Cathedral of Coimbra, Portugal (UNESCO World Heritage Site)