181 research outputs found
Looking for signatures of sex-specific demography and local adaptation on the X chromosome
A genome-wide study of X chromosome genetic diversity in human populations shows the impact of social organization and local adaptation
Transmission of Migration Propensity Increases Genetic Divergence Between Populations
The advent of molecular genetics has brought invaluable information, which is now routinely used by anthropologists in their attempt to reconstruct our demographic past. Since the mitochondrial DNA loci are much more similar between populations than are the Y chromosome loci, it has been suggested that women had a much higher migration rate than men throughout history. Based on an examination of intergenerational migration patterns in three large demographic databases, we bring this inference into question. In some early Canadian settlements (St. Lawrence Valley and Saguenay), and in the past Krummhörn region of Northwest Germany, men whose father was a migrant were more likely to migrate, while the migration probability of women was largely independent of that of their mothers. As a result, menâs movements were less effective in preventing genetic differentiation between populations than womenâs movements. If it is largely prevalent among human societies, this male-specific transmission of migration propensity could partly explain the geographical clustering of Y chromosome distributions. In order to account for its impact, we propose a slight modification of Wrightâs Island model. We also address the relevance of this model with respect to previously reported measures of population differentiation and we discuss the supporting historical and anthropological literature. We conclude that the widespread patrilocal rules of post-marital residence have generated both a higher female migration rate and a patrilineal dependency in the propensity to migrate
Matrilineal Fertility Inheritance Detected in HunterâGatherer Populations Using the Imbalance of Gene Genealogies
Fertility inheritance, a phenomenon in which an individual's number of offspring is positively correlated with his or her number of siblings, is a cultural process that can have a strong impact on genetic diversity. Until now, fertility inheritance has been detected primarily using genealogical databases. In this study, we develop a new method to infer fertility inheritance from genetic data in human populations. The method is based on the reconstruction of the gene genealogy of a sample of sequences from a given population and on the computation of the degree of imbalance in this genealogy. We show indeed that this level of imbalance increases with the level of fertility inheritance, and that other phenomena such as hidden population structure are unlikely to generate a signal of imbalance in the genealogy that would be confounded with fertility inheritance. By applying our method to mtDNA samples from 37 human populations, we show that matrilineal fertility inheritance is more frequent in hunterâgatherer populations than in food-producer populations. One possible explanation for this result is that in hunterâgatherer populations, individuals belonging to large kin networks may benefit from stronger social support and may be more likely to have a large number of offspring
ContinuitĂ© gĂ©nĂ©tique des populations anciennes et rĂ©centes dâAsie Centrale
Depuis la prĂ©histoire, lâAsie centrale mĂ©ridionale est une rĂ©gion au carrefour des mouvements de populations, de cultures et de marchandises. Aujourdâhui lâAsie Centrale est peuplĂ©e par des populations rĂ©parties dans deux groupes culturels et linguistiques : le groupe Indo-iranien et le groupe Turco-mongol. LâĂ©tablissement dâune base de donnĂ©es gĂ©nĂ©tiques sur ces populations a permis dâĂ©tudier leur structure gĂ©nĂ©tique en mettant en Ă©vidence la migration de populations dâAsie de lâest Ă lâorig..
beDNA : un projet visant Ă la collection systĂ©matique dâĂ©chantillons humains archĂ©ologiques Ă vocation palĂ©ogĂ©nĂ©tique â une premiĂšre expĂ©rimentation
La palĂ©ogĂ©nĂ©tique occupe dĂ©sormais une place importante dans les problĂ©matiques archĂ©ologiques. Toutefois, les analyses dâADN ancien peuvent ĂȘtre desservies, voire empĂȘchĂ©es, par lâĂ©tat de prĂ©servation des Ă©chantillons en raison de contamination par de lâADN moderne ou de mauvaises conditions de stockage. Le projet beDNA, "banque dâĂ©chantillons et de DonnĂ©es Nationale ArchĂ©ogĂ©nĂ©tique", souhaite donner les moyens dâanalyses palĂ©ogĂ©nĂ©tiques futures, en proposant le stockage systĂ©matique dâĂ©chantillons des squelettes humains tenant compte des contraintes inhĂ©rentes Ă la prĂ©servation de lâADN ancien. Le projet implique (1) un protocole systĂ©matique dâĂ©chantillonnage "propre" des restes humains sur le terrain commun Ă toutes les opĂ©rations archĂ©ologiques, (2) un espace de stockage dĂ©diĂ© Ă ces Ă©chantillons adaptĂ© Ă la conservation de lâADN ancien, (3) une base de donnĂ©es faisant le lien entre les sites et les Ă©chantillons conservĂ©s dans la banque, (4) lâapprobation par lâĂtat des demandes dâanalyse dâĂ©chantillons aprĂšs expertise. La phase de test du projet, initiĂ©e en septembre 2020 sur la rĂ©gion Ăle-de-France, nous a permis dâĂ©valuer et dâajuster le protocole dâĂ©chantillonnage sur le terrain et les dispositifs de transfert vers la banque. Cette note prĂ©sente les Ă©tapes envisagĂ©es pour chaque Ă©chantillon, depuis les terrains jusquâaux laboratoires dâanalyse gĂ©nĂ©tique, ainsi que le dĂ©roulement de sa phase test, en cours, et les premiers retours dâexpĂ©rience.Palaeogenetics is becoming increasingly important in tackling archaeological issues. However, analyses of ancient DNA can be hampered or even prevented by the state of preservation of samples due to poor storage conditions, and because of contamination by modern DNA. The beDNA project for a national archaeological genetic data and sample bank (banque dâĂ©chantillons et de DonnĂ©es Nationale ArchĂ©ogĂ©nĂ©tique) is developing the means to enable future palaeogenetic analyses by systematically storing human skeletal samples, with the constraints inherent to the preservation of ancient DNA taken into account. This project comprises (1) a systematic protocol for "clean" sampling of human remains to be common to all archaeological operations, (2) a dedicated storage space for samples, suited to aDNA preservation, (3) a database linking sites with the samples stored in the bank, (4) approval of sample analysis requests by authorities, after expert review. The test phase of the project, which began in September 2020 in the Ăle-de-France region, enabled us to evaluate and adjust both the sampling protocol in the field and the transfer process to the beDNA bank. This note describes the different stages envisaged for each sample, from the archaeological field to the genetics laboratory, as well as the development of the experimental phase and initial feedback from it
Interview with Laura Fortunato, Winner of the 2011 Gabriel W. Lasker Prize
An international jury composed of Michael Crawford (University of Kansas, USA), Dennis O\u27Rourke (University of Utah, USA), and Stephen Shennan (University College London, UK) has awarded the Gabriel Ward Lasker Prize 2011 to Dr. Laura Fortunato for her articles entitled Reconstructing the History of Residence Strategies in Indo-EuropeanâSpeaking Societies and Reconstructing the History of Marriage Strategies in Indo-EuropeanâSpeaking Societies considered as the best contribution to the 83rd volume of Human Biology (2011). Laura Fortunato is an Omidyar Fellow at the Santa Fe Institute in Santa Fe, New Mexico. She received her Ph.D. in anthropology from University College London in 2009; her doctoral research focused on the evolution of kinship and marriage systems. In particular, she has investigated the evolution of marriage strategies, wealth transfers at marriage, residence strategies, and inheritance strategies. Laura\u27s current research activities apply conceptual and methodological tools developed in evolutionary biology to a diverse range of topics in anthropology, from matrilineal kinship organization to cultural evolution
Genetic diversity and the emergence of ethnic groups in Central Asia
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
The epigenomic landscape of African rainforest hunter-gatherers and farmers
International audienceThe genetic history of African populations is increasingly well documented, yet their patterns of epigenomic variation remain uncharacterized. Moreover, the relative impacts of DNA sequence variation and temporal changes in lifestyle and habitat on the human epigenome remain unknown. Here we generate genome-wide genotype and DNA methylation profiles for 362 rainforest hunter-gatherers and sedentary farmers. We find that the current habitat and historical lifestyle of a population have similarly critical impacts on the methylome, but the biological functions affected strongly differ. Specifically, methylation variation associated with recent changes in habitat mostly concerns immune and cellular functions, whereas that associated with historical lifestyle affects developmental processes. Furthermore, methylation variationâparticularly that correlated with historical lifestyleâshows strong associations with nearby genetic variants that, moreover, are enriched in signals of natural selection. Our work provides new insight into the genetic and environmental factors affecting the epigenomic landscape of human populations over time
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