RESUMO
Determining the functional consequences of karyotypic changes is invariably challenging because evolution tends to obscure many of its own footprints, such as accumulated mutations, recombination events, and demographic perturbations. Here, we describe the assembly of a chromosome-level reference genome of the gayal (Bos frontalis) thereby revealing the structure, at base-pair-level resolution, of a telo/acrocentric-to-telo/acrocentric Robertsonian translocation (2;28) (T/A-to-T/A rob[2;28]). The absence of any reduction in the recombination rate or genetic introgression within the fusion region of gayal served to challenge the long-standing view of a role for fusion-induced meiotic dysfunction in speciation. The disproportionate increase noted in the distant interactions across pro-chr2 and pro-chr28, and the change in open-chromatin accessibility following rob(2;28), may, however, have led to the various gene expression irregularities observed in the gayal. Indeed, we found that many muscle-related genes, located synthetically on pro-chr2 and pro-chr28, exhibited significant changes in expression. This, combined with genome-scale structural variants and expression alterations in genes involved in myofibril composition, may have driven the rapid sarcomere adaptation of gayal to its rugged mountain habitat. Our findings not only suggest that large-scale chromosomal changes can lead to alterations in genome-level expression, thereby promoting both adaptation and speciation, but also illuminate novel avenues for studying the relationship between karyotype evolution and speciation.
Assuntos
Cromatina , Genoma , Animais , BovinosRESUMO
Photodetectors are one of the most critical components for future optoelectronic systems and it undergoes significant advancements to meet the growing demands of diverse applications spanning the spectrum from ultraviolet (UV) to terahertz (THz). 2D materials are very attractive for photodetector applications because of their distinct optical and electrical properties. The atomic-thin structure, high carrier mobility, low van der Waals (vdWs) interaction between layers, relatively narrower bandgap engineered through engineering, and significant absorption coefficient significantly benefit the chip-scale production and integration of 2D materials-based photodetectors. The extremely sensitive detection at ambient temperature with ultra-fast capabilities is made possible with the adaptability of 2D materials. Here, the recent progress of photodetectors based on 2D materials, covering the spectrum from UV to THz is reported. In this report, the interaction of light with 2D materials is first deliberated on in terms of optical physics. Then, various mechanisms on which detectors work, important performance parameters, important and fruitful fabrication methods, fundamental optical properties of 2D materials, various types of 2D materials-based detectors, different strategies to improve performance, and important applications of photodetectors are discussed.
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Much like other indigenous domesticated animals, Tibetan chickens living at high altitudes (2,200-4,100 m) show specific physiological adaptations to the extreme environmental conditions of the Tibetan Plateau, but the genetic bases of these adaptations are not well characterized. Here, we assembled a de novo genome of a Tibetan chicken and resequenced whole genomes of 32 additional chickens, including Tibetan chickens, village chickens, game fowl, and Red Junglefowl, and found that the Tibetan chickens could broadly be placed into two groups. Further analyses revealed that several candidate genes in the calcium-signaling pathway are possibly involved in adaptation to the hypoxia experienced by these chickens, as these genes appear to have experienced directional selection in the two Tibetan chicken populations, suggesting a potential genetic mechanism underlying high altitude adaptation in Tibetan chickens. The candidate selected genes identified in this study, and their variants, may be useful targets for clarifying our understanding of the domestication of chickens in Tibet, and might be useful in current breeding efforts to develop improved breeds for the highlands.
Assuntos
Adaptação Fisiológica/genética , Altitude , Galinhas/genética , Genoma , Animais , Sinalização do Cálcio/genética , Genética Populacional , Seleção Genética , TibetRESUMO
With the assistance of their human companions, dogs have dispersed into new environments during the expansion of human civilization. Tibetan Mastiff (TM), a native of the Tibetan Plateau, was derived from the domesticated Chinese native dog and, like Tibetans, has adapted to the extreme environment of high altitude. Here, we genotyped genome-wide single-nucleotide polymorphisms (SNPs) from 32 TMs and compared them with SNPs from 20 Chinese native dogs and 14 gray wolves (Canis lupus). We identified 16 genes with signals of positive selection in the TM, with 12 of these candidate genes associated with functions that have roles in adaptation to high-altitude adaptation, such as EPAS1, SIRT7, PLXNA4, and MAFG that have roles in responses to hypoxia. This study provides important information on the genetic diversity of the TM and potential mechanisms for adaptation to hypoxia.
Assuntos
Aclimatação/genética , Altitude , Cães/genética , Cães/fisiologia , Aclimatação/fisiologia , Animais , China , Cães/classificação , Evolução Molecular , Variação Genética , Genética Populacional , Genoma , Humanos , Modelos Genéticos , Animais de Estimação/classificação , Animais de Estimação/genética , Animais de Estimação/fisiologia , Filogenia , Polimorfismo de Nucleotídeo Único , Tibet , Lobos/genéticaRESUMO
We analyzed genetic diversity of 215 mitochondrial DNA (mtDNA) D-loop sequences from seven populations of domesticated helmeted guinea fowl (Numida meleagris) in Nigeria and compared that with results of samples collected in Kenya (n = 4) and China (n = 22). In total, 241 sequences were assigned to 22 distinct haplotypes. Haplotype diversity in Nigeria was 0.693 ± 0.022. The network grouped most matrilines into two main haplogroups: A and B. There was an absence of a geographic signal, and two haplotypes dominated across all locations with the exception of the Kebbi population in the northwest of the country; AMOVA also confirmed this observation (FST = 0.035). The low genetic diversity may be a result of recent domestication, whereas the lack of maternal genetic structure likely suggests the extensive genetic intermixing within the country. Additionally, the differentiation of the Kebbi population may be due to a certain demographic history and/or artificial selection that shaped its haplotype profile. The current data do not permit us to make further conclusions; therefore, more research evidence from genetics and archaeology is still required.
Assuntos
Animais Domésticos/genética , DNA Mitocondrial/genética , Galliformes/genética , Variação Genética , Genética Populacional , Animais , China , Haplótipos , Quênia , Dados de Sequência MolecularRESUMO
Frequently, Pleistocene climatic cycling has been found to be the diver of genetic structuring in populations, even in areas that did not have continental ice sheets, such as on the Qinghai-Tibetan Plateau (QTP). Typically, species distributed on the plateau have been hypothesized to re-treat to south-eastern refugia, especially during the Last Glacial Maximum (LGM). We evaluated sequence variation in the mitochondrial DNA gene Cytb and the nuclear DNA gene RAG-1 in Rana kukunoris, a species endemic to the QTP. Two major lineages, N and S, were identified, and lineage N was further subdivided into N1 and N2. The geographical distribution and genealogical divergences supported the hypothesis of multiple refugia. However, major lineages and sublineages diverged prior to the LGM. Demographical expansion was detected only in lineage S and sublineage N2. Sublineage N1 might have survived several glacial cycles in situ and did not expand after the LGM because of the absence of suitable habitat; it survived in river islands. Genetic analysis and environment modelling suggested that the north-eastern edge of QTP contained a major refugium for R. kukunoris. From here, lineage S dispersed southwards after the LGM. Two microrefugia in northern Qilian Mountains greatly contributed to current level of intraspecific genetic diversity. These results were found to have important implications for the habitat conservation in Northwest China.
Assuntos
Variação Genética , Genética Populacional , Filogenia , Ranidae/genética , Animais , Núcleo Celular/genética , China , DNA Mitocondrial/genética , Geografia , Haplótipos , Ilhas , Dinâmica Populacional , Rios , Análise de Sequência de DNARESUMO
Background: The Tibetan Plateau has an abundance of yak milk resources. The complex microbiota found in traditional fermented yak milk produced and sold by local Tibetans endows the yak milk with unique quality characteristics such as tissue morphology, flavor, and function. However, the diversity of bacterial flora in traditional fermented yak milk have not been elucidated. Methods: In this study, 15 samples of fermented yak milk were collected for 16S rRNA high-throughput sequencing to analyze the bacterial community composition and function. Results: After filtering for quality, 792,642 high-quality sequences were obtained, and 13 kinds of different phyla and 82 kinds of different genera were identified, of which the phylum Firmicutes (98.94%) was the dominant phylum, Lactobacillus (64.73%) and Streptococcus (28.48%) were identified as the dominant genus, in addition, the bacterial community richness and diversity were higher in Manang Village, followed by Bola Village. Bacterial community richness and diversity in Huage Village were relatively low. Based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) functional classification, the microorganisms in traditional fermented yak milk have rich metabolic functions (77.60%). These findings suggest that a large number of bacteria in traditional fermented yak milk contain abundant metabolic genes and can carry out a variety of growth and metabolic activities. This study established a theoretical foundation for further exploring the microbial flora of traditional fermented yak milk in Gannan.
Assuntos
Bactérias , Leite , Animais , Bovinos , Leite/microbiologia , Tibet , RNA Ribossômico 16S/genética , Bactérias/genética , Sequenciamento de Nucleotídeos em Larga EscalaRESUMO
In order to achieve a thorough coverage of the basal lineages in the Chinese matrilineal pool, we have sequenced the mitochondrial DNA (mtDNA) control region and partial coding region segments of 6,093 mtDNAs sampled from 84 populations across China. By comparing with the available complete mtDNA sequences, 194 of those mtDNAs could not be firmly assigned into the available haplogroups. Completely sequencing 51 representatives selected from these unclassified mtDNAs identified a number of novel lineages, including five novel basal haplogroups that directly emanate from the Eurasian founder nodes (M and N). No matrilineal contribution from the archaic hominid was observed. Subsequent analyses suggested that these newly identified basal lineages likely represent the genetic relics of modern humans initially peopling East Asia instead of being the results of gene flow from the neighboring regions. The observation that most of the newly recognized mtDNA lineages have already differentiated and show the highest genetic diversity in southern China provided additional evidence in support of the Southern Route peopling hypothesis of East Asians. Specifically, the enrichment of most of the basal lineages in southern China and their rather ancient ages in Late Pleistocene further suggested that this region was likely the genetic reservoir of modern humans after they entered East Asia.
Assuntos
Povo Asiático/genética , DNA Mitocondrial/análise , Etnicidade/genética , Genética Populacional , Sequência de Bases , Ásia Oriental , Variação Genética , Haplótipos , Humanos , Dados de Sequência Molecular , Análise de Sequência de DNARESUMO
Milk consumption is prevalent in daily diets of Tibetans. To digest the milk sugar lactose, lactase persistence (LP) should be required. However, little is known about the genetic basis of LP in Tibetans. We screened 495 Tibetan individuals for five previously reported single-nucleotide polymorphisms (SNPs): -13907C/G (rs41525747), -13910C/T (rs4988235), -13915T/G (rs41380347), -14010G/C and -22018G/A (rs182549), which are associated with the LP in populations from a vast region surrounding Tibet. The five SNPs were nearly absent in Tibetan populations, suggesting LP likely to have an independent origin in Tibetans rather than to be introduced via gene flow from neighboring populations. We identified three novel SNPs (-13838G/A, -13906T/A and -13908C/T) in Tibetans. In particular, -13838G/A might be functional as it is located in the binding motif for HNF4α that acts as a transcription factor for intestinal gene expression. To investigate the potential association of this variant with LP, further detailed studies are required in the future.
Assuntos
Povo Asiático/genética , Lactase/genética , Lactase/metabolismo , Alelos , Sítios de Ligação , Elementos Facilitadores Genéticos , Frequência do Gene , Estudos de Associação Genética , Humanos , Motivos de Nucleotídeos , Polimorfismo de Nucleotídeo Único , TibetRESUMO
Himalayas was believed to be a formidably geographical barrier between South and East Asia. The observed high frequency of the East Eurasian paternal lineages in Nepal led some researchers to suggest that these lineages were introduced into Nepal from Tibet directly; however, it is also possible that the East Eurasian genetic components might trace their origins to northeast India where abundant East Eurasian maternal lineages have been detected. To trace the origin of the Nepalese maternal genetic components, especially those of East Eurasian ancestry, and then to better understand the role of the Himalayas in peopling Nepal, we have studied the matenal genetic composition extensively, especially the East Eurasian lineages, in Nepalese and its surrounding populations. Our results revealed the closer affinity between the Nepalese and the Tibetans, specifically, the Nepalese lineages of the East Eurasian ancestry generally are phylogenetically closer with the ones from Tibet, albeit a few mitochondrial DNA haplotypes, likely resulted from recent gene flow, were shared between the Nepalese and northeast Indians. It seems that Tibet was most likely to be the homeland for most of the East Eurasian in the Nepalese. Taking into account the previous observation on Y chromosome, now it is convincing that bearer of the East Eurasian genetic components had entered Nepal across the Himalayas around 6 kilo years ago (kya), a scenario in good agreement with the previous results from linguistics and archeology.
Assuntos
DNA Mitocondrial/genética , Genética Populacional , Genoma Humano , Genoma Mitocondrial , Mitocôndrias/genética , Povo Asiático/genética , Cromossomos Humanos Y/genética , DNA Mitocondrial/classificação , Fluxo Gênico , Haplótipos , Humanos , Índia , Nepal , Filogenia , Análise de Componente Principal , Análise de Sequência de DNA , Tibet , Fatores de TempoRESUMO
Due to its numerous environmental extremes, the Tibetan Plateau--the world's highest plateau--is one of the most challenging areas of modern human settlement. Archaeological evidence dates the earliest settlement on the plateau to the Late Paleolithic, while previous genetic studies have traced the colonization event(s) to no earlier than the Neolithic. To explore whether the genetic continuity on the plateau has an exclusively Neolithic time depth, we studied mitochondrial DNA (mtDNA) genome variation within 6 regional Tibetan populations sampled from Tibet and neighboring areas. Our results confirm that the vast majority of Tibetan matrilineal components can trace their ancestry to Epipaleolithic and Neolithic immigrants from northern China during the mid-Holocene. Significantly, we also identified an infrequent novel haplogroup, M16, that branched off directly from the Eurasian M founder type. Its nearly exclusive distribution in Tibetan populations and ancient age (>21 kya) suggest that M16 may represent the genetic relics of the Late Paleolithic inhabitants on the plateau. This partial genetic continuity between the Paleolithic inhabitants and the contemporary Tibetan populations bridges the results and inferences from archaeology, history, and genetics.
Assuntos
Emigração e Imigração , Genoma Mitocondrial/genética , Paleontologia , Sequência de Bases , China , Efeito Fundador , Variação Genética , História Antiga , Humanos , Dados de Sequência Molecular , TibetRESUMO
BACKGROUND: Interspecific hybridization may lead to the introgression of genes and genomes across species barriers and contribute to a reticulate evolutionary pattern and thus taxonomic uncertainties. Since several previous studies have demonstrated that introgressive hybridization has occurred among some species within Lepus, therefore it is possible that introgressive hybridization events also occur among Chinese Lepus species and contribute to the current taxonomic confusion. RESULTS: Data from four mtDNA genes, from 116 individuals, and one nuclear gene, from 119 individuals, provides the first evidence of frequent introgression events via historical and recent interspecific hybridizations among six Chinese Lepus species. Remarkably, the mtDNA of L. mandshuricus was completely replaced by mtDNA from L. timidus and L. sinensis. Analysis of the nuclear DNA sequence revealed a high proportion of heterozygous genotypes containing alleles from two divergent clades and that several haplotypes were shared among species, suggesting repeated and recent introgression. Furthermore, results from the present analyses suggest that Chinese hares belong to eight species. CONCLUSION: This study provides a framework for understanding the patterns of speciation and the taxonomy of this clade. The existence of morphological intermediates and atypical mitochondrial gene genealogies resulting from frequent hybridization events likely contribute to the current taxonomic confusion of Chinese hares. The present study also demonstrated that nuclear gene sequence could offer a powerful complementary data set with mtDNA in tracing a complete evolutionary history of recently diverged species.
Assuntos
Núcleo Celular/genética , DNA Mitocondrial/genética , Evolução Molecular , Lebres/genética , Hibridização Genética , Animais , China , Feminino , Haplótipos , Lebres/classificação , Masculino , Dados de Sequência Molecular , FilogeniaRESUMO
Development of thoracolumbar vertebra (TLV) and rib primordium (RP) is a common evolutionary feature across vertebrates, although whole-organism analysis of the expression dynamics of TLV- and RP-related genes has been lacking. Here, we investigated the single-cell transcriptome landscape of thoracic vertebra (TV), lumbar vertebra (LV), and RP cells from a pig embryo at 27â¯days post-fertilization (dpf) and identified six cell types with distinct gene expression signatures. In-depth dissection of the gene expression dynamics and RNA velocity revealed a coupled process of osteogenesis and angiogenesis during TLV and RP development. Further analysis of cell type-specific and strand-specific expression uncovered the extremely high level of HOXA10 3'-UTR sequence specific to osteoblasts of LV cells, which may function as anti-HOXA10-antisense by counteracting the HOXA10-antisense effect to determine TLV transition. Thus, this work provides a valuable resource for understanding embryonic osteogenesis and angiogenesis underlying vertebrate TLV and RP development at the cell type-specific resolution, which serves as a comprehensive view on the transcriptional profile of animal embryo development.
Assuntos
Coluna Vertebral , Transcriptoma , Animais , Costelas , Análise de Sequência de RNA , Análise de Célula Única , Suínos/genéticaRESUMO
Hakka and Chaoshanese are two unique Han populations residing in southern China but with northern Han (NH) cultural traditions and linguistic influences. Although most of historical records indicate that both populations migrated from northern China in the last two thousand years, no consensus on their origins has been reached so far. To shed more light on the origins of Hakka and Chaoshanese, mitochondrial DNAs (mtDNAs) of 170 Hakka from Meizhou and 102 Chaoshanese from Chaoshan area, Guangdong Province, were analyzed. Our results show that some southern Chinese predominant haplogroups, e.g. B, F, and M7, have relatively high frequencies in both populations. Although median network analyses show that Hakka/Chaoshanese share some haplotypes with NH, interpopulation comparison reveals that both populations show closer affinity with southern Han (SH) populations than with NH. In consideration of previous results from nuclear gene (including Y chromosome) research, it is likely that matrilineal landscapes of both Hakka and Chaoshanese have largely been shaped by the local people during their migration southward and/or later colonization in southern China, and factors such as cultural assimilation, patrilocality, and even sex-bias in the immigrants might have played important roles during the process.
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Povo Asiático/história , DNA Mitocondrial/química , Povo Asiático/genética , China , Emigração e Imigração , Haplótipos , História Antiga , Humanos , Dinâmica Populacional , Análise de Componente Principal , Alinhamento de Sequência , Análise de Sequência de DNARESUMO
Pangolins are among the most critically endangered animals due to heavy poaching and worldwide trafficking. However, their demographic histories and the genomic consequences of their recent population declines remain unknown. We generated high-quality de novo reference genomes for critically endangered Malayan (Manis javanica, MJ) and Chinese (M. pentadactyla, MP) pangolins and re-sequencing population genomic data from 74 MJs and 23 MPs. We recovered the population identities of illegally traded pangolins and previously unrecognized genetic populations that should be protected as evolutionarily distinct conservation units. Demographic reconstruction suggested environmental changes have resulted in a population size fluctuation of pangolins. Additionally, recent population size declines due to human activities have resulted in an increase in inbreeding and genetic load. Deleterious mutations were enriched in genes related to cancer/diseases and cholesterol homeostasis, which may have increased their susceptibility to diseases and decreased their survival potential to adapt to environmental changes and high-cholesterol diets. This comprehensive study provides not only high-quality pangolin reference genomes, but also valuable information concerning the driving factors of long-term population size fluctuations and the genomic impact of recent population size declines due to human activities, which is essential for pangolin conservation management and global action planning.
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Molecular studies on donkey mitochondrial sequences have clearly defined two distinct maternal lineages involved in domestication. However, domestication histories of these two lineages remain enigmatic. We therefore compared several population characteristics between these two lineages based on global sampling, which included 171 sequences obtained in this study (including Middle Asian, East Asian, and African samples) plus 536 published sequences (including European, Asian, and African samples). The two lineages were clearly separated from each other based on whole mitochondrial genomes and partial non-coding displacement loop (D-loop) sequences, respectively. The Clade I lineage experienced an increase in population size more than 8 000 years ago and shows a complex haplotype network. In contrast, the population size of the Clade II lineage has remained relatively constant, with a simpler haplotype network. Although the distribution of the two lineages was almost equal across the Eurasian mainland, they still presented discernible but complex geographic bias in most parts of Africa, which are known as their domestication sites. Donkeys from sub-Saharan Africa tended to descend from the Clade I lineage, whereas the Clade II lineage was dominant along the East and North coasts of Africa. Furthermore, the migration routes inferred from diversity decay suggested different expansion across China between the two lineages. Altogether, these differences indicated non-simultaneous domestication of the two lineages, which was possibly influenced by the response of pastoralists to the desertification of the Sahara and by the social expansion and trade of ancient humans in Northeast Africa, respectively.
Assuntos
DNA Mitocondrial/genética , Domesticação , Equidae/genética , Variação Genética , Filogenia , Animais , HaplótiposRESUMO
Overexploitation, habitat destruction, human-driven climate change and disease spread are resulting in the extinction of innumerable species, with amphibians being hit harder than most other groups [1]. Few species of amphibians are widespread, and those that are often represent complexes of multiple cryptic species. This is especially true for range-restricted salamanders [2]. Here, we used the widespread and critically endangered Chinese giant salamander (Andrias davidianus) to show how genetically uninformed management efforts can negatively affect species conservation. We find that this salamander consists of at least five species-level lineages. However, the extensive recent translocation of individuals between farms, where the vast majority of extant salamanders now live, has resulted in genetic homogenization. Mitochondrial DNA (mtDNA) haplotypes from northern China now predominate in farms. Unfortunately, hybrid offspring are being released back into the wild under well-intentioned, but misguided, conservation management. Our findings emphasize the necessity of genetic assessments for seemingly well-known, widespread species in conservation initiatives. Species serve as the primary unit for protection and management in conservation actions [3], so determining the taxonomic status of threatened species is a major concern, especially for amphibians. The level of threat to amphibians may be underestimated, and existing conservation strategies may be inadvertently harmful if conducted without genetic assessment.
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Conservação dos Recursos Naturais/métodos , Espécies em Perigo de Extinção , Variação Genética , Hibridização Genética , Urodelos , Animais , Ecossistema , Genética Populacional , Urodelos/classificação , Urodelos/genéticaRESUMO
The Pamirs, among the world's highest mountains in Central Asia, are one of homelands with the most extreme high altitude for several ethnic groups. The settlement history of modern humans on the Pamirs remains still opaque. Herein, we have sequenced the mitochondrial DNA (mtDNA) genomes of 382 individuals belonging to eight populations from the Pamirs and the surrounding lowlands in Central Asia. We construct the Central Asian (including both highlanders and lowlanders) mtDNA haplogroup tree at the highest resolution. All the matrilineal components are assigned into the defined mtDNA haplogroups in East and West Eurasians. No basal lineages that directly emanate from the Eurasian founder macrohaplogroups M, N, and R are found. Our data support the origin of Central Asian being the result of East-West Eurasian admixture. The coalescence ages for more than 93% mtDNA lineages in Central Asians are dated after the last glacial maximum (LGM). The post-LGM and/or later dispersals/admixtures play dominant roles in shaping the maternal gene pool of Central Asians. More importantly, our analyses reveal the mtDNA heterogeneity in the Pamir highlanders, not only between the Turkic Kyrgyz and the Indo-European Tajik groups, but also among three highland Tajiks. No evidence supports positive selection or relaxation of selective constraints in the mtDNAs of highlanders as compared to that of lowlanders. Our results suggest a complex history for the peopling of Pamirs by multiple waves of migrations from various genetic resources during different time scales.
Assuntos
Povo Asiático/genética , Evolução Molecular , Genoma Mitocondrial , Migração Humana , Adulto , Ásia Central , China , Feminino , Efeito Fundador , Haplótipos , Humanos , Masculino , Herança Materna , LinhagemRESUMO
Domestic dogs have an ancient origin and a long history in Africa. Nevertheless, the timing and sources of their introduction into Africa remain enigmatic. Herein, we analyse variation in mitochondrial DNA (mtDNA) D-loop sequences from 345 Nigerian and 37 Kenyan village dogs plus 1530 published sequences of dogs from other parts of Africa, Europe and West Asia. All Kenyan dogs can be assigned to one of three haplogroups (matrilines; clades): A, B, and C, while Nigerian dogs can be assigned to one of four haplogroups A, B, C, and D. None of the African dogs exhibits a matrilineal contribution from the African wolf (Canis lupus lupaster). The genetic signal of a recent demographic expansion is detected in Nigerian dogs from West Africa. The analyses of mitochondrial genomes reveal a maternal genetic link between modern West African and North European dogs indicated by sub-haplogroup D1 (but not the entire haplogroup D) coalescing around 12,000 years ago. Incorporating molecular anthropological evidence, we propose that sub-haplogroup D1 in West African dogs could be traced back to the late-glacial dispersals, potentially associated with human hunter-gatherer migration from southwestern Europe.
Assuntos
DNA Mitocondrial/genética , Cães/genética , África Ocidental , Animais , Europa (Continente) , Variação Genética , Haplótipos , Filogenia , Análise de Sequência de DNARESUMO
To characterize the origin, genetic diversity, and phylogeographic structure of Chinese domestic sheep, we here analyzed a 531-bp fragment of mtDNA control region of 449 Chinese autochthonous sheep from 19 breeds/populations from 13 geographic regions, together with previously reported 44 sequences from Chinese indigenous sheep. Phylogenetic analysis showed that all three previously defined lineages A, B, and C were found in all sampled Chinese sheep populations, except for the absence of lineage C in four populations. Network profiles revealed that the lineages B and C displayed a star-like phylogeny with the founder haplotype in the centre, and that two star-like subclades with two founder haplotypes were identified in lineage A. The pattern of genetic variation in lineage A, together with the divergence time between the two central founder haplotypes suggested that two independent domestication events have occurred in sheep lineage A. Considerable mitochondrial diversity was observed in Chinese sheep. Weak structuring was observed either among Chinese indigenous sheep populations or between Asian and European sheep and this can be attributable to long-term strong gene flow induced by historical human movements. The high levels of intra-population diversity in Chinese sheep and the weak phylogeographic structuring indicated three geographically independent domestication events have occurred and the domestication place was not only confined to the Near East, but also occurred in other regions.