Project description:Over the past few years, studies of DNA isolated from human fossils and archaeological remains have generated considerable novel insight into the history of our species. Several landmark papers have described the genomes of ancient human ancestors and have demonstrated that contemporary humans harbour genetic material from ancient close relatives, the Neanderthals and Denisovans, and that ancient human individuals are often genetically distinct from nearby extant populations whilst also showing affinities with populations from further afield. Across West Eurasia, there is growing genetic evidence of large-scale, dynamic population movements over the period between 10,000 to 2,000 years ago, such that the ancestry across present-day populations is likely to be a mixture of several ancient groups. Whilst these efforts are bringing the details of West Eurasian prehistory into increasing focus, studies aimed at understanding the processes behind the generation of the current West Eurasian genetic landscape have been limited by the number of populations sampled, or have been either too regional or global in their outlook. Here, using recently described haplotype-based techniques, we present the results of a systematic survey of recent admixture history across Western Eurasia and show that admixture is a universal property across almost all groups. Admixture in all regions except North Western Europe involved the influx of genetic material from outside of West Eurasia, which we date to specific time periods. Within Northern, Western, and Central Europe, admixture tended to occur between local groups during the period 300 to 1200CE. Comparisons of the genetic profiles of West Eurasians before and after admixture show that population movements within the last 1500 years are likely to have maintained differentiation amongst groups. Our analysis provides a timeline of the gene flow events that have generated the contemporary genetic landscape of West Eurasia. 20 individuals from Croatia included as part of an analysis of admixture in West Eurasia

Project description:Over the past few years, studies of DNA isolated from human fossils and archaeological remains have generated considerable novel insight into the history of our species. Several landmark papers have described the genomes of ancient human ancestors and have demonstrated that contemporary humans harbour genetic material from ancient close relatives, the Neanderthals and Denisovans, and that ancient human individuals are often genetically distinct from nearby extant populations whilst also showing affinities with populations from further afield. Across West Eurasia, there is growing genetic evidence of large-scale, dynamic population movements over the period between 10,000 to 2,000 years ago, such that the ancestry across present-day populations is likely to be a mixture of several ancient groups. Whilst these efforts are bringing the details of West Eurasian prehistory into increasing focus, studies aimed at understanding the processes behind the generation of the current West Eurasian genetic landscape have been limited by the number of populations sampled, or have been either too regional or global in their outlook. Here, using recently described haplotype-based techniques, we present the results of a systematic survey of recent admixture history across Western Eurasia and show that admixture is a universal property across almost all groups. Admixture in all regions except North Western Europe involved the influx of genetic material from outside of West Eurasia, which we date to specific time periods. Within Northern, Western, and Central Europe, admixture tended to occur between local groups during the period 300 to 1200CE. Comparisons of the genetic profiles of West Eurasians before and after admixture show that population movements within the last 1500 years are likely to have maintained differentiation amongst groups. Our analysis provides a timeline of the gene flow events that have generated the contemporary genetic landscape of West Eurasia.

Project description:Interethnic variability in chemotherapy response is becoming increasingly evident, making approaches for customizing chemotherapy treatment to different ethnic populations desirable. At the same time, significant genetic variation has also been observed between ethnic groups, including many germline and somatic pharmacogenetic variants involved in chemotherapy pharmacology. Recently, based on meta-analyses of studies on germline pharmacogenetic variant frequencies and clinical trials, the investigators found that chemotherapy outcomes between Asians and Caucasians colorectal cancer (CRC) patients could potentially be inferred from the frequencies of variants between the ethnic groups and their respective biological functions. In this study, the investigators seek to further clarify the validity of using pharmacogenetic variants to customize chemotherapy between ethnicities through the following specific aims: (1) To verify the differences observed in the frequency of germline pharmacogenetic variants related to chemotherapy between Asian and Caucasian CRC patients, (2) To test whether variations in the frequency of somatic pharmacogenetic gene mutations between Asian and Caucasian CRC patients could be used to infer differences in clinical outcomes between the two ethnicities. (3) (4) For Aim 1, DNA samples from approximately 1000 Asian and Caucasian CRC patients each will be analyzed for the frequency of a panel of germline pharmacogenetic variants identified in our meta-analyses using high-throughput methodology. For Aim 2, meta-analyses will be performed on pharmacogenetic studies and clinical trials to establish the relative frequencies of somatic variants and clinical outcomes in Asian and Caucasian CRC patients. These frequencies will be verified on the same series of DNA samples used in Aim 1. The clinical outcomes inferred from the frequency differences and biological functions will then be compared to those summarized from clinical trials. This data could provide a basis for developing a rational approach to customizing chemotherapy in non-Caucasian populations and improve assessment of drug feasibility in different ethnic populations.If validated, this working hypothesis would be of high clinical interest, giving the opportunity to use this as a DNA prognosis biomarker in CRC. Pharmacogenetic frequencies could be a potentially useful approach for predicting likely chemotherapy outcomes in non-Caucasian populations

Project description:The domestication is an evolutionary process during which individuals will progressively adapt to an environment controlled by humans. It is accompanied by epigenetic and genetic modifications potentially leading to modifications in the transcriptomic profile in various tissues. The reproduction process is among the biological functions highly affected whatever the species and/or the way of domestication. Indeed, the reproduction success often decreases in domesticated populations. For fish, the molecular content of the eggs is crucial for the proper embryogenesis. Among these molecules the mRNA content depends directly from the gene expression and thus may reflect the genetic modifications occurring during this process. Here, we investigated the transcriptomic profile of eggs coming from females of two populations (F1 and Fx) that were reared in the same conditions and were genetically close. Our main goal was thus to determine how the domestication process may affect the reproduction success in the Eurasian perch and if it was mediated by the regulation of the transcription in the eggs. A regular follow up of the oogenesis progression showed few differences of the hormonal production between the two populations. Nevertheless, the histological study showed that the F1 females were more developed by the end of the oogenesis induction than the domesticated ones and as a result, they spawned earlier than the domesticated ones. The study of the early developmental success revealed significant differences between the populations. The microarray analysis of unfertilized eggs presented more than 350 transcripts differently expressed between the two populations. Among them, some specific genes were drastically more expressed in the domesticated (mex3B, hace1 and an uncharacterized protein) or F1 (per) populations. Our data show that the F1 population is more sensitive to the environmental conditions to advance oogenesis and reach the spawning season earlier. The transcriptomic profiles in eggs coming from the two populations were different and may lead to developmental impairments having a potential link with the domestication process. Further analyses are needed to explain these differences.

Dataset Information

Afghan Hindu Kush: where Eurasian sub-continent gene flows converge

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets