Molecular Adaptation of Modern Human Populations

Modern humans have gone through varied processes of genetic adaptations when their ancestors left Africa about 100,000 years ago. The environmental stresses and the social transitions (e.g., emergence of the Neolithic culture) have been acting as the major selective forces reshaping the genetic make-up of human populations. Genetic adaptations have occurred in many aspects of human life, including the adaptation to cold climate and high-altitude hypoxia, the improved ability of defending infectious diseases, and the polished strategy of utilizing new diet with the advent of agriculture. At the same time, the adaptations once developed during evolution may sometimes generate deleterious effects (e.g., susceptibility to diseases) when facing new environmental and social changes. The molecular (especially the genome-wide screening of genetic variations) studies in recent years have detected many genetic variants that show signals of Darwinian positive selection in modern human populations, which will not only provide a better understanding of human evolutionary history, but also help dissecting the genetic basis of human complex diseases.

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Relationship between the genetic structure of human populations and geographical and climatic parameters

Nauchno-prakticheskii zhurnal «Medicinskaia genetika» ◽

10.25557/2073-7998.2018.01.37-40 ◽

2018 ◽

pp. 37-40

Author(s):

А.А. Попович ◽

К.В. Вагайцева ◽

А.В. Бочарова ◽

В.А. Степанов

Keyword(s):

Genetic Diversity ◽

Modern Human ◽

Cold Climate ◽

Human Populations ◽

Genetic Constitution ◽

Nucleotide Polymorphisms ◽

Climatic Parameters ◽

Single Nucleotide ◽

Variability Analysis ◽

The Earth

Популяции человека проживают в различных условиях среды обитания, которые требуют адаптации, особенно к экстремальным средовым факторам. Действие адаптивной эволюции отражается и на генетической структуре популяций человека. В настоящем исследовании был проведен анализ вариабельности 25 однонуклеотидных полиморфизмов (SNP), связанных с адаптацией к холодному климату, в мировых популяциях. Показано влияние климатических и географических факторов на генетическое разнообразие популяций человека. Выявлен рост генетического разнообразия по изученным маркерам от Африки по мере расселения современного человека по земному шару. Вероятно, высокая частота аллелей, ассоциированных с адаптацией к климату, в некоторых популяциях человека может быть объяснена в рамках гипотезы канализации/деканализации геном-феномных отношений в ходе расселения современного человека. Human populations live in different environmental conditions that require adaptation, especially to extreme environmental factors. The action of adaptive evolution is also reflected on human populations’ genetic constitution. The study highlights the variability analysis of 25 SNPs single nucleotide polymorphisms (SNP) related to adaptation to a cold climate, as well as influence of climatic and geographical factors on the genetic diversity of human populations. The growth of the genetic diversity among the studied markers from Africa according to a modern human’s displacement around the earth identified. Probably, the variability of alleles associated with adaptation to climate in some populations could be explained in the framework of the hypothesis of canalization/decanalization of genome-phenome relationships under natural selection during modern human dispersion.

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Denisovan Ancestry in East Eurasian and Native American Populations.

10.1101/017475 ◽

2015 ◽

Cited By ~ 1

Author(s):

Pengfei Qin ◽

Mark Stoneking

Keyword(s):

Native American ◽

Gene Flow ◽

New Guinea ◽

Modern Human ◽

Common Source ◽

Human Populations ◽

Snp Data ◽

Genome Wide ◽

Or Gene ◽

The Relationship

Although initial studies suggested that Denisovan ancestry was found only in modern human populations from island Southeast Asia and Oceania, more recent studies have suggested that Denisovan ancestry may be more widespread. However, the geographic extent of Denisovan ancestry has not been determined, and moreover the relationship between the Denisovan ancestry in Oceania and that elsewhere has not been studied. Here we analyze genome-wide SNP data from 2493 individuals from 221 worldwide populations, and show that there is a widespread signal of a very low level of Denisovan ancestry across Eastern Eurasian and Native American (EE/NA) populations. We also verify a higher level of Denisovan ancestry in Oceania than that in EE/NA; the Denisovan ancestry in Oceania is correlated with the amount of New Guinea ancestry, but not the amount of Australian ancestry, indicating that recent gene flow from New Guinea likely accounts for signals of Denisovan ancestry across Oceania. However, Denisovan ancestry in EE/NA populations is equally correlated with their New Guinea or their Australian ancestry, suggesting a common source for the Denisovan ancestry in EE/NA and Oceanian populations. Our results suggest that Denisovan ancestry in EE/NA is derived either from common ancestry with, or gene flow from, the common ancestor of New Guineans and Australians, indicating a more complex history involving East Eurasians and Oceanians than previously suspected.

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Evolutionary and Medical Consequences of Archaic Introgression into Modern Human Genomes

Genes ◽

10.3390/genes9070358 ◽

2018 ◽

Vol 9 (7) ◽

pp. 358 ◽

Cited By ~ 10

Author(s):

Olga Dolgova ◽

Oscar Lao

Keyword(s):

Demographic History ◽

Modern Human ◽

Human Populations ◽

Human Genomes ◽

Fitness Consequences ◽

Genome Wide ◽

Anatomically Modern Humans ◽

Genome Wide Data ◽

History Of ◽

Health And Disease

The demographic history of anatomically modern humans (AMH) involves multiple migration events, population extinctions and genetic adaptations. As genome-wide data from complete genome sequencing becomes increasingly abundant and available even from extinct hominins, new insights of the evolutionary history of our species are discovered. It is currently known that AMH interbred with archaic hominins once they left the African continent. Current non-African human genomes carry fragments of archaic origin. This review focuses on the fitness consequences of archaic interbreeding in current human populations. We discuss new insights and challenges that researchers face when interpreting the potential impact of introgression on fitness and testing hypotheses about the role of selection within the context of health and disease.

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Evolutionary and Medical Consequences of Archaic Introgression into Modern Human Genomes

10.20944/preprints201806.0287.v1 ◽

2018 ◽

Cited By ~ 2

Author(s):

Olga Dolgova ◽

Oscar Lao

Keyword(s):

Demographic History ◽

Modern Human ◽

Human Populations ◽

Human Genomes ◽

Fitness Consequences ◽

Genome Wide ◽

Anatomically Modern Humans ◽

Genome Wide Data ◽

History Of ◽

Health And Disease

The demographic history of anatomically modern humans (AMH) involves multiple migration events, population extinctions and genetic adaptations. As genome-wide data from complete genome sequencing becomes increasingly abundant and available even from extinct hominins, new insights of the evolutionary history of our species are discovered. It is currently known that AMH introgressed with archaic hominins once they left the African continent. Current out of African human genomes carry fragments of archaic origin. This review focuses on the fitness consequences of archaic interbreeding in current human populations. We discuss new insights and challenges that researchers face when interpreting the potential impact of introgression on fitness and testing hypotheses about the role of selection within the context of health and disease.

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Human Prehistoric Demography Revealed by the Polymorphic Pattern of CpG Transitions

Molecular Biology and Evolution ◽

10.1093/molbev/msaa112 ◽

2020 ◽

Vol 37 (9) ◽

pp. 2691-2698 ◽

Cited By ~ 2

Author(s):

Xiaoming Liu

Keyword(s):

Population Dynamics ◽

Population Expansion ◽

Future Research ◽

Human Populations ◽

Neolithic Revolution ◽

Cpg Sites ◽

Hunting And Gathering ◽

Genome Wide ◽

Polymorphic Pattern ◽

Improved Model

Abstract The prehistoric demography of human populations is an essential piece of information for illustrating our evolution. Despite its importance and the advancement of ancient DNA studies, our knowledge of human evolution is still limited, which is also the case for relatively recent population dynamics during and around the Holocene. Here, we inferred detailed demographic histories from 1 to 40 ka for 24 population samples using an improved model-flexible method with 36 million genome-wide noncoding CpG sites. Our results showed many population growth events that were likely due to the Neolithic Revolution (i.e., the shift from hunting and gathering to agriculture and settlement). Our results help to provide a clearer picture of human prehistoric demography, confirming the significant impact of agriculture on population expansion, and provide new hypotheses and directions for future research.

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A computational reward learning account of social media engagement

Nature Communications ◽

10.1038/s41467-020-19607-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Björn Lindström ◽

Martin Bellander ◽

David T. Schultner ◽

Allen Chang ◽

Philippe N. Tobler ◽

...

Keyword(s):

Social Media ◽

Human Behavior ◽

Computational Models ◽

Average Rate ◽

Human Life ◽

Modern Human ◽

Reward Learning ◽

Learning Mechanisms ◽

Social Media Engagement ◽

Social Rewards

AbstractSocial media has become a modern arena for human life, with billions of daily users worldwide. The intense popularity of social media is often attributed to a psychological need for social rewards (likes), portraying the online world as a Skinner Box for the modern human. Yet despite such portrayals, empirical evidence for social media engagement as reward-based behavior remains scant. Here, we apply a computational approach to directly test whether reward learning mechanisms contribute to social media behavior. We analyze over one million posts from over 4000 individuals on multiple social media platforms, using computational models based on reinforcement learning theory. Our results consistently show that human behavior on social media conforms qualitatively and quantitatively to the principles of reward learning. Specifically, social media users spaced their posts to maximize the average rate of accrued social rewards, in a manner subject to both the effort cost of posting and the opportunity cost of inaction. Results further reveal meaningful individual difference profiles in social reward learning on social media. Finally, an online experiment (n = 176), mimicking key aspects of social media, verifies that social rewards causally influence behavior as posited by our computational account. Together, these findings support a reward learning account of social media engagement and offer new insights into this emergent mode of modern human behavior.

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Initial Upper Palaeolithic humans in Europe had recent Neanderthal ancestry

Nature ◽

10.1038/s41586-021-03335-3 ◽

2021 ◽

Vol 592 (7853) ◽

pp. 253-257 ◽

Cited By ~ 3

Author(s):

Mateja Hajdinjak ◽

Fabrizio Mafessoni ◽

Laurits Skov ◽

Benjamin Vernot ◽

Alexander Hübner ◽

...

Keyword(s):

Family History ◽

East Asia ◽

Late Pleistocene ◽

Modern Human ◽

Human Migration ◽

Upper Palaeolithic ◽

Modern Humans ◽

Genome Wide ◽

Genome Wide Data

AbstractModern humans appeared in Europe by at least 45,000 years ago1–5, but the extent of their interactions with Neanderthals, who disappeared by about 40,000 years ago6, and their relationship to the broader expansion of modern humans outside Africa are poorly understood. Here we present genome-wide data from three individuals dated to between 45,930 and 42,580 years ago from Bacho Kiro Cave, Bulgaria1,2. They are the earliest Late Pleistocene modern humans known to have been recovered in Europe so far, and were found in association with an Initial Upper Palaeolithic artefact assemblage. Unlike two previously studied individuals of similar ages from Romania7 and Siberia8 who did not contribute detectably to later populations, these individuals are more closely related to present-day and ancient populations in East Asia and the Americas than to later west Eurasian populations. This indicates that they belonged to a modern human migration into Europe that was not previously known from the genetic record, and provides evidence that there was at least some continuity between the earliest modern humans in Europe and later people in Eurasia. Moreover, we find that all three individuals had Neanderthal ancestors a few generations back in their family history, confirming that the first European modern humans mixed with Neanderthals and suggesting that such mixing could have been common.

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Genome-wide SNP data of Izumo and Makurazaki populations support inner-dual structure model for origin of Yamato people

Journal of Human Genetics ◽

10.1038/s10038-020-00898-3 ◽

2021 ◽

Author(s):

Timothy Jinam ◽

Yosuke Kawai ◽

Yoichiro Kamatani ◽

Shunro Sonoda ◽

Kanro Makisumi ◽

...

Keyword(s):

Phylogenetic Network ◽

Principal Component ◽

Human Populations ◽

Structure Model ◽

Rice Farming ◽

Asian Continent ◽

Dual Structure ◽

Snp Data ◽

Genome Wide ◽

Kagoshima Prefecture

AbstractThe “Dual Structure” model on the formation of the modern Japanese population assumes that the indigenous hunter-gathering population (symbolized as Jomon people) admixed with rice-farming population (symbolized as Yayoi people) who migrated from the Asian continent after the Yayoi period started. The Jomon component remained high both in Ainu and Okinawa people who mainly reside in northern and southern Japan, respectively, while the Yayoi component is higher in the mainland Japanese (Yamato people). The model has been well supported by genetic data, but the Yamato population was mostly represented by people from Tokyo area. We generated new genome-wide SNP data using Japonica Array for 45 individuals in Izumo City of Shimane Prefecture and for 72 individuals in Makurazaki City of Kagoshima Prefecture in Southern Kyushu, and compared these data with those of other human populations in East Asia, including BioBank Japan data. Using principal component analysis, phylogenetic network, and f4 tests, we found that Izumo, Makurazaki, and Tohoku populations are slightly differentiated from Kanto (including Tokyo), Tokai, and Kinki regions. These results suggest the substructure within Mainland Japanese maybe caused by multiple migration events from the Asian continent following the Jomon period, and we propose a modified version of “Dual Structure” model called the “Inner-Dual Structure” model.

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Language and life history: A new perspective on the development and evolution of human language

Behavioral and Brain Sciences ◽

10.1017/s0140525x0600906x ◽

2006 ◽

Vol 29 (3) ◽

pp. 259-280 ◽

Cited By ~ 103

Author(s):

John L. Locke ◽

Barry Bogin

Keyword(s):

Life History ◽

Adult Development ◽

Homo Sapiens ◽

Human Life ◽

Modern Human ◽

Linguistic Knowledge ◽

Human Language ◽

Juvenile Period ◽

Development Of Language ◽

New Perspective

It has long been claimed that Homo sapiens is the only species that has language, but only recently has it been recognized that humans also have an unusual pattern of growth and development. Social mammals have two stages of pre-adult development: infancy and juvenility. Humans have two additional prolonged and pronounced life history stages: childhood, an interval of four years extending between infancy and the juvenile period that follows, and adolescence, a stage of about eight years that stretches from juvenility to adulthood. We begin by reviewing the primary biological and linguistic changes occurring in each of the four pre-adult ontogenetic stages in human life history. Then we attempt to trace the evolution of childhood and juvenility in our hominin ancestors. We propose that several different forms of selection applied in infancy and childhood; and that, in adolescence, elaborated vocal behaviors played a role in courtship and intrasexual competition, enhancing fitness and ultimately integrating performative and pragmatic skills with linguistic knowledge in a broad faculty of language. A theoretical consequence of our proposal is that fossil evidence of the uniquely human stages may be used, with other findings, to date the emergence of language. If important aspects of language cannot appear until sexual maturity, as we propose, then a second consequence is that the development of language requires the whole of modern human ontogeny. Our life history model thus offers new ways of investigating, and thinking about, the evolution, development, and ultimately the nature of human language.

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