Increased Neanderthal ancestry in genomic regions associated with lipid catabolism in contemporary Europeans
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ABSTRACT: While Neanderthals are extinct, fragments of their genome still persist in the genomes of contemporary humans. Here, we show that such Neanderthal-like sequences are not distributed randomly in contemporary human genomes. Specifically, while genome-wide frequency of Neanderthal-like sites is close to 6% in all out-of-Africa populations, genes involved in lipid catabolism contain large excess Neanderthal-like sequences in Europeans (24.3%), but not in Asians (12.4%). While lipid catabolism cannot be assayed in Neanderthals, we took advantage of genetic divergence between human populations, chimpanzees and Neanderthals to predict metabolic divergence expected from the observed excess of Neanderthal gene flow into Europeans. We confirmed predicted changes in lipid catabolism using hydrophobic metabolome measurements in the brain tissue and further linked these metabolic changes to gene expression divergence.
Project description:While Neanderthals are extinct, fragments of their genome still persist in the genomes of contemporary humans. Here, we show that such Neanderthal-like sequences are not distributed randomly in contemporary human genomes. Specifically, while genome-wide frequency of Neanderthal-like sites is close to 6% in all out-of-Africa populations, genes involved in lipid catabolism contain large excess Neanderthal-like sequences in Europeans (24.3%), but not in Asians (12.4%). While lipid catabolism cannot be assayed in Neanderthals, we took advantage of genetic divergence between human populations, chimpanzees and Neanderthals to predict metabolic divergence expected from the observed excess of Neanderthal gene flow into Europeans. We confirmed predicted changes in lipid catabolism using hydrophobic metabolome measurements in the brain tissue and further linked these metabolic changes to gene expression divergence. 14 human and 6 chimpanzee samples were sequenced.
Project description:Humans co-existed and interbred with other hominins which later became extinct. These archaic hominins are known to us only through fossil records and for two cases, genome sequences. Here we engineer Neanderthal and Denisovan sequences into thousands of artificial genes to reconstruct the pre-mRNA processing patterns of these extinct populations. Of the 5,224 alleles tested in this massively parallel splicing reporter assay (MaPSy), we report 969 exonic splicing mutations (ESMs) that correspond to differences in exon recognition between extant and extinct hominins. Using MaPSy splicing variants, predicted splicing variants, and splicing quantitative trait loci, we show that splice-disrupting variants experienced greater purifying selection in anatomically modern humans than in Neanderthals. Adaptively introgressed variants were enriched for moderate effect splicing variants, consistent with positive selection for alternative spliced alleles following introgression. As particularly compelling examples, we characterized a novel tissue-specific alternative splicing variant at the adaptively introgressed innate immunity gene TLR1, as well as a novel Neanderthal introgressed alternative splicing variant in the gene HSPG2 that encodes perlecan. We further identified potentially pathogenic splicing variants found only in Neanderthals and Denisovans in genes related to sperm maturation and immunity. Finally, we found splicing variants that may contribute to variation among modern humans in total bilirubin, balding, hemoglobin levels, and lung capacity. Our findings provide novel insights into natural selection acting on splicing in human evolution and demonstrate how functional assays can be used to identify candidate causal variants underlying differences in gene regulation and phenotype.
Project description:Denisovans are an extinct hominin group defined by ancient genomes of Middle to Late Pleistocene fossils from southern Siberia. Although genomic evidence suggests their widespread distribution throughout eastern Asia and possibly Oceania, so far only a few fossils from the Altai and Tibet are confidently identified molecularly as Denisovan. We identified a hominin mandible (Penghu 1) from Taiwan (10,000 to 70,000 years ago or 130,000 to 190,000 years ago) as belonging to a male Denisovan by applying ancient protein analysis. We retrieved 4241 amino acid residues and identified two Denisovan-specific variants. The increased fossil sample of Denisovans demonstrates their wider distribution, including warm and humid regions, as well as their shared distinct robust dentognathic traits that markedly contrast with their sister group, Neanderthals.
Project description:Regulatory changes are broadly accepted as key drivers of phenotypic divergence. However, identifying regulatory changes that underlie human-specific traits has proven very challenging. Here, we use 63 DNA methylation maps of ancient and present-day humans, as well as of six chimpanzees, to detect differentially methylated regions that emerged in modern humans after the split from Neanderthals and Denisovans. We show that genes affecting the face and vocal tract went through particularly extensive methylation changes. Specifically, we identify widespread hypermethylation in a network of face- and voice-affecting genes (SOX9, ACAN, COL2A1, NFIX and XYLT1). We propose that these repression patterns appeared after the split from Neanderthals and Denisovans, and that they might have played a key role in shaping the modern human face and vocal tract
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:For a long time, Neanderthals were considered hunters of large mammals, whereas the diversification of the exploited faunal spectrum to include smaller taxa, including birds, was assumed to be specific to anatomically modern humans. In recent decades, archaeozoological analyses of faunal remains from layers associated with Middle Palaeolithic lithic industries have revealed traces of human manipulation of small taxa, indicating the exploitation of a wider range of animals than previously thought, including small or fast-moving animals such as molluscs, leporids and birds. These new data have challenged the view that Neanderthals did not exploit small animals, thereby narrowing the behavioral gap with anatomically modern humans. Nevertheless, the information currently available comes almost exclusively from southern Europe and the nature of Neanderthal small fauna exploitation in northern Europe remains largely unknown. The present study aims to fill this gap by applying archaeozoological methods, including detailed taphonomic and traceological analyses, to 118 bird remains recovered from levels containing Middle Palaeolithic industries at Scladina cave, southern Belgium. Analyses of proteomics were applied to clarify the taxonomic identity of two morphologically non-diagnostic elements. Compared to mammal remains, bird bones, most of which belong to the order Galliformes, are scarce at Scladina Cave. This is likely due to conservation bias. Traces of non-human predators or scavengers, suggest that mammalian carnivores are responsible for accumulating a considerable portion of the avian assemblage. In total, seven bird bones exhibit anthropogenic traces, and one element presents questionable traces. Various Galliformes and a cormorant were exploited likely for their meat, during MIS 5 and/or 6 and MIS 6. The terminal posterior phalanx (talon) of a raptor of the size of a pomarine eagle displays intense polishing that could be linked to human manipulation of this element (MIS 5 and/or 6), although in the absence of tool marks this remains hypothetical at this stage. On the radius of a Western capercaillie, two deep incisions may indicate bone working, and intense use-wear on one of the fractured ends indicates that the bone has been utilized, potentially on soft organic material (MIS 6). This study provides the first evidence of the exploitation of birds during the Middle Palaeolithic in Belgium and constitutes the only detailed archaeozoological analysis of bird material in northwestern Europe. The likely transformation and use of a bird bone is only the second example recovered from Neanderthal occupations. The novel taxa identified as Neanderthal prey highlight the plasticity of Neanderthal ecological behavior, adapting to different landscapes and climates and exploiting the full spectrum of locally available prey.
Project description:The ancient preserved molecules in bones offer the opportunity to gain a better knowledge on the biological past. In recent years, bones proteomics has become an attractive method to study extinct species and phylogenetic evolution as an alternative to DNA analysis which is limited by DNA amplification present in ancient samples and its contamination. The analysis of fossils must consume a low quantity of material to avoid damaging the samples. Another difficulty is the absence of genomic data for most of the extinct species. This study applied a proteomic methodology to mammalian bones of 130,000 / 120,000 years old from the last Chibanian and the earlier Upper Pleistocene site of Waziers (France). The presence of lithic artefacts and the traces of butchery observed on the bones indicate the presence of Neanderthal Man on this site. Starting from 5 milligram samples, our results show that most detected peptides match collagen I alpha 1 and alpha 2 proteins with a sequence coverage up to 60 %. Using sequence homology with modern sequences, a biological classification was successfully achieved. Each bone taxonomic rank by proteomics was consistent with the existing osteomorphological studies and palaeoenvironmental and palaeodietary data.