Neanderthal Contribution to the Modern Human Gene Pool is Minor (original) (raw)
Related papers
Neanderthal DNA and modern human origins
Quaternary International, 2013
Available online xxx a b s t r a c t Neanderthals are an extinct hominid lineage that coexisted with modern humans in Eurasia. The Neanderthal's role in the evolutionary history of modern humans is a well concerned topic. Mitochondrial DNA sequences from Neanderthal fossils support the "Out of Africa" theory of human evolution, suggesting that modern human ancestors replaced Neanderthal populations in Eurasia. Recent analyses of Neanderthal genome draft sequences indicate minor gene flow between Neanderthals and modern humans in Eurasia but not in Africa. However, these conclusions are quite controversial due to data quality and insufficient sampling, especially about when and where the genetic admixture took place, and the direction of the assumed gene flow.
Ancient gene flow from early modern humans into Eastern Neanderthals
Nature, 2016
It has been shown that Neanderthals contributed genetically to modern humans outside Africa 47,000-65,000 years ago. Here we analyse the genomes of a Neanderthal and a Denisovan from the Altai Mountains in Siberia together with the sequences of chromosome 21 of two Neanderthals from Spain and Croatia. We find that a population that diverged early from other modern humans in Africa contributed genetically to the ancestors of Neanderthals from the Altai Mountains roughly 100,000 years ago. By contrast, we do not detect such a genetic contribution in the Denisovan or the two European Neanderthals. We conclude that in addition to later interbreeding events, the ancestors of Neanderthals from the Altai Mountains and early modern humans met and interbred, possibly in the Near East, many thousands of years earlier than previously thought.
Reconstructing the genetic history of late Neanderthals
Although it has previously been shown that Neanderthals contributed DNA to modern humans 1,2 , not much is known about the genetic diversity of Neanderthals or the relationship between late Neanderthal populations at the time at which their last interactions with early modern humans occurred and before they eventually disappeared. Our ability to retrieve DNA from a larger number of Neanderthal individuals has been limited by poor preservation of endogenous DNA 3 and contamination of Neanderthal skeletal remains by large amounts of microbial and present-day human DNA 3-5. Here we use hypochlorite treatment 6 of as little as 9 mg of bone or tooth powder to generate between 1-and 2.7-fold genomic coverage of five Neanderthals who lived around 39,000 to 47,000 years ago (that is, late Neanderthals), thereby doubling the number of Neanderthals for which genome sequences are available. Genetic similarity among late Neanderthals is well predicted by their geographical location, and comparison to the genome of an older Neanderthal from the Caucasus 2,7 indicates that a population turnover is likely to have occurred, either in the Caucasus or throughout Europe, towards the end of Neanderthal history. We find that the bulk of Neanderthal gene flow into early modern humans originated from one or more source populations that diverged from the Neanderthals that were studied here at least 70,000 years ago, but after they split from a previously sequenced Neanderthal from Siberia 2 around 150,000 years ago. Although four of the Neanderthals studied here postdate the putative arrival of early modern humans into Europe, we do not detect any recent gene flow from early modern humans in their ancestry.
Gene, 2013
Human evolution Analyses of the genetic relationships and interactions among modern humans, Neanderthals and Denisovans have suggested that 1-4% of the non-Sub-Saharan African gene pool may be Neanderthal derived, while 6-8% of the Melanesian gene pool may be the product of admixture between the Denisovans and the direct ancestors of Melanesians. In the present study, we analyzed single nucleotide polymorphism (SNP) diversity among a worldwide collection of contemporary human populations with respect to the genetic constitution of these two archaic hominids and Pan troglodytes (chimpanzee). We partitioned SNPs into subsets, including those that are derived in both archaic lineages, those that are ancestral in both archaic lineages and those that are only derived in one archaic lineage. By doing this, we have conducted separate examinations of subsets of mutations with higher probabilities of divergent phylogenetic origins. While previous investigations have excluded SNPs from common ancestors in principal component analyses, we included common ancestral SNPs in our analyses to visualize the relative placement of the Neanderthal and Denisova among human populations. To assess the genetic similarities among the various hominid lineages, we performed genetic structure analyses to provide a comparison of genetic patterns found within contemporary human genomes that may have archaic or common ancestral roots. Our results indicate that 3.6% of the Neanderthal genome is shared with roughly 65.4% of the average European gene pool, which clinally diminishes with distance from Europe. Our results suggest that Neanderthal genetic associations with contemporary non-Sub-Saharan African populations, as well as the genetic affinities observed between Denisovans and Melanesians most likely result from the retention of ancient mutations in these populations.
Evaluating Neanderthal Genetics and Phylogeny
Journal of Molecular Evolution, 2007
The retrieval of Neanderthal (Homo neanderthalsensis) mitochondrial DNA is thought to be among the most significant ancient DNA contributions to date, allowing conflicting hypotheses on modern human (Homo sapiens) evolution to be tested directly. Recently, however, both the authenticity of the Neanderthal sequences and their phylogenetic position outside contemporary human diversity have been questioned. Using Bayesian inference and the largest dataset to date, we find strong support for a monophyletic Neanderthal clade outside the diversity of contemporary humans, in agreement with the expectations of the Out-of-Africa replacement model of modern human origin. From average pairwise sequence differences, we obtain support for claims that the first published Neanderthal sequence may include errors due to postmortem damage in the template molecules for PCR. In contrast, we find that recent results implying that the Neanderthal sequences are products of PCR artifacts are not well supported, suffering from inadequate experimental design and a presumably high percentage (>68%) of chimeric sequences due to ''jumping PCR'' events.
About Neanderthals: Relations and reproduction from an European prospect
2024
Currently, the existence of the Neanderthal genome in our DNA is an undeniable fact. The European territory provides us with several archaeological sites which fossil record demonstrates this evidence. Neanderthals formed small communities, but interbred with other species and with other Neanderthal groups. The severity and intensity of these relationships, along with the chronologies, genetic indices and occupations within the European context, are highlighted in the current study.
Journal of Human Evolution, 2010
A better understanding of the evolutionary relationship between modern humans and Neanderthals is essential for improving the resolution of hominin phylogenetic hypotheses. Currently, four distinct chronologies for the timing of population divergence are available, ranging from the late Middle Pleistocene to the late Early Pleistocene, each based on different interpretations of hominin taxonomy. Genetic data can present an independent estimate of the evolutionary timescale involved, making it possible to distinguish between these competing models of hominin evolution. We analysed five dated Neanderthal mitochondrial genomes, together with those of 54 modern humans, and inferred a genetic chronology using multiple age calibrations. Our mean date estimates are consistent with a process of genetic divergence within an ancestral population, commencing approximately 410e440 ka. These results suggest that a reappraisal of key elements in the Pleistocene hominin fossil record may now be required.