1,721,067 research outputs found
The evolutionary history of Southern Africa
Full text linkThe genomic variability of Southern African groups is characterised by an exceptional degree
of diversity, which is the result of long-term local evolutionary history, migrations and
gene-flow. Over the last few years several investigations have characterized the signatures of
these processes, revealing how ancient and more recent events have shaped the structure and
ancestry composition of local populations. Here we discuss recent insights into the genetic
history of the Southernmost part of the African continent provided by the analysis of modern
and ancient genomes. Future work is expected to clarify the population dynamics associated
with the emergence of H. sapiens across Africa and the details of the process of dispersion
and admixture associated with the arrival of Bantu-speaking groups in the region
Group membership, geography and shared ancestry: Genetic variation in the Basotho of Lesotho.
No full textObjectives The investigation of the evolution of cultural and genetic traits and how they interact represents a vibrant area of research in evolutionary genetics, whose dynamics are particularly relevant for our species. One of the key assumptions of the "gene-culture coevolution" framework is the coinheritance of cultural and genetic traits. A corollary of the model is that culturally defined groups with a unique (or a limited number of) common origin(s) whose membership is inherited only through the male or female line are expected to show a relatively low intragroup variation for genetic markers similarly transmitted. Across human societies this is expected to be the case for cultural toponymies and family names within patrilineal and matrilineal groups considered in association with the nonrecombining region of the Y chromosome (NRY) and the mitochondrial DNA (mtDNA) portion of the genome, respectively. This study aims at exploring the degree of correlation between culture and genetics by investigating the genetic variation of culturally and geographically defined groups. Methods We analyzed the genetic variation at NRY and mtDNA in 181 individuals from the Basotho, a Southern African patrilineal population from Lesotho, in combination with information about group membership and geographic origin. Results Our results show that (a) the genetic distance between individuals belonging to the same culturally defined group is lower than the population as a whole when NRY markers are considered; (b) cultural traits have a bigger impact than geography for the within-group variation of Y chromosome, but not mtDNA; and (c) within-group genetic variation is compatible with a more homogeneous origin for less common groups. Conclusions Our results provided additional evidence for the relevance of the dual inheritance model (culture and genetics) in understanding the patterns of human genetic variation, as implied by gene-culture coevolution theory
Searching for archaic contribution in Africa
No full textContext: Africa’s role in the narrative of human evolution is indisputably emphasised in the emergence of Homo sapiens. However, once humans dispersed beyond Africa, the history of those who stayed remains vastly under-studied, lacking the proper attention the birthplace of both modern and archaic humans deserves. The sequencing of Neanderthal and Denisovan genomes has elucidated evidence of admixture between archaic and modern humans outside of Africa, but has not aided efforts in answering whether archaic admixture happened within Africa. Objectives: This article reviews the state of research for archaic introgression in African populations and discusses recent insights into this topic. Methods: Gathering published sources and recently released preprints, this review reports on the different methods developed for detecting archaic introgression. Particularly it discusses how relevant these are when implemented on African populations and what findings these studies have shown so far. Results: Methods for detecting archaic introgression have been predominantly developed and implemented on non-African populations. Recent preprints present new methods considering African populations. While a number of studies using these methods suggest archaic introgression in Africa, without an African archaic genome to validate these results, such findings remain as putative archaic introgression. Conclusion: In light of the caveats with implementing current archaic introgression detection methods in Africa, we recommend future studies to concentrate on unravelling the complicated demographic history of Africa through means of ancient DNA where possible and through more focused efforts to sequence modern DNA from more representative populations across the African continent
A worldwide map of human structural variants
Full text linkGenomic variation extends from single nucleotide variants to large chromosomal rearrangements, but the extent of structural variation in Homo sapiens is still unclear. Almarri et al. provide a worldwide catalogue of structural variants present in human populations. Most of the reported variation is novel, with some variants being inherited from Neanderthals and Denisovans. Drift and selection shaped the distribution of these variants with some suggested to have functional implications
Influence of students’ motivation on the experience with e-learning systems: an experimental study
No full textThe use of information technologies to Support learning is an important study area for both teaching experts and HCI researchers aiming to produce efficacious e-learning systems allowing teachers, tutors and students to carry out their activities in a satisfactory and enjoyable manner. The system the user will interact with must therefore be designed not only on the basis of the classic usability principles but also of those aspects that affect the overall user experience. Aim of the present study is to see how individual characteristics of cognitive and above all motivational type affect learning while using an e-learning system, and to assess their impact on the overall e-learning user experience
Revisiting the out of Africa event with a deep-learning approach
Full text linkAnatomically modern humans evolved around 300 thousand years ago in Africa. They started to appear in the fossil record outside of Africa as early as 100 thousand years ago, although other hominins existed throughout Eurasia much earlier. Recently, several studies argued in favor of a single out of Africa event for modern humans on the basis of whole-genome sequence analyses. However, the single out of Africa model is in contrast with some of the findings from fossil records, which support two out of Africa events, and uniparental data, which propose a back to Africa movement. Here, we used a deep-learning approach coupled with approximate Bayesian computation and sequential Monte Carlo to revisit these hypotheses from the whole-genome sequence perspective. Our results support the back to Africa model over other alternatives. We estimated that there are two sequential separations between Africa and out of African populations happening around 60-90 thousand years ago and separated by 13-15 thousand years. One of the populations resulting from the more recent split has replaced the older West African population to a large extent, while the other one has founded the out of Africa populations
On the relation between students’ motivation and their experience with e-learning systems
No full text- …
