- MeSH
- antropologie metody MeSH
- genom lidský genetika MeSH
- lidé MeSH
- neandertálci genetika MeSH
- populační genetika MeSH
- starobylá DNA * analýza izolace a purifikace MeSH
- tok genů genetika MeSH
- vývoj člověka MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
The Sahel/Savannah belt harbors diverse populations with different demographic histories and different subsistence patterns. However, populations from this large African region are notably under-represented in genomic research. To investigate the population structure and adaptation history of populations from the Sahel/Savannah space, we generated dense genome-wide genotype data of 327 individuals-comprising 14 ethnolinguistic groups, including 10 previously unsampled populations. Our results highlight fine-scale population structure and complex patterns of admixture, particularly in Fulani groups and Arabic-speaking populations. Among all studied Sahelian populations, only the Rashaayda Arabic-speaking population from eastern Sudan shows a lack of gene flow from African groups, which is consistent with the short history of this population in the African continent. They are recent migrants from Saudi Arabia with evidence of strong genetic isolation during the last few generations and a strong demographic bottleneck. This population also presents a strong selection signal in a genomic region around the CNR1 gene associated with substance dependence and chronic stress. In Western Sahelian populations, signatures of selection were detected in several other genetic regions, including pathways associated with lactase persistence, immune response, and malaria resistance. Taken together, these findings refine our current knowledge of genetic diversity, population structure, migration, admixture and adaptation of human populations in the Sahel/Savannah belt and contribute to our understanding of human history and health.
The role of adaptive divergence in the formation of new species has been the subject of much recent debate. The most direct evidence comes from traits that can be shown to have diverged under natural selection and that now contribute to reproductive isolation. Here, we investigate differential adaptation of two fire-bellied toads (Anura, Bombinatoridae) to two types of aquatic habitat. Bombina bombina and B. variegata are two anciently diverged taxa that now reproduce in predator-rich ponds and ephemeral aquatic sites, respectively. Nevertheless, they hybridise extensively wherever their distribution ranges adjoin. We show in laboratory experiments that, as expected, B. variegata tadpoles are at relatively greater risk of predation from dragonfly larvae, even when they display a predator-induced phenotype. These tadpoles spent relatively more time swimming and so prompted more attacks from the visually hunting predators. We argue in the discussion that genomic regions linked to high activity in B. variegata should be barred from introgression into the B. bombina gene pool and thus contribute to gene flow barriers that keep the two taxa from merging into one.
- MeSH
- chování zvířat MeSH
- druhová specificita MeSH
- ekosystém MeSH
- fylogeneze MeSH
- fyziologická adaptace fyziologie MeSH
- hybridizace genetická MeSH
- larva genetika metabolismus MeSH
- predátorské chování fyziologie MeSH
- selekce (genetika) MeSH
- tok genů genetika MeSH
- úniková reakce fyziologie MeSH
- žáby embryologie genetika metabolismus MeSH
- zeměpis MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Speciation mechanisms remain controversial. Two speciation models occur in Israeli subterranean mole rats, genus Spalax: a regional speciation cline southward of four peripatric climatic chromosomal species and a local, geologic-edaphic, genic, and sympatric speciation. Here we highlight their genome evolution. The five species were separated into five genetic clusters by single nucleotide polymorphisms, copy number variations (CNVs), repeatome, and methylome in sympatry. The regional interspecific divergence correspond to Pleistocene climatic cycles. Climate warmings caused chromosomal speciation. Triple effective population size, Ne , declines match glacial cold cycles. Adaptive genes evolved under positive selection to underground stresses and to divergent climates, involving interspecies reproductive isolation. Genomic islands evolved mainly due to adaptive evolution involving ancient polymorphisms. Repeatome, including both CNV and LINE1 repetitive elements, separated the five species. Methylation in sympatry identified geologically chalk-basalt species that differentially affect thermoregulation, hypoxia, DNA repair, P53, and other pathways. Genome adaptive evolution highlights climatic and geologic-edaphic stress evolution and the two speciation models, peripatric and sympatric.
- MeSH
- biologická adaptace MeSH
- biologická evoluce * MeSH
- epigeneze genetická MeSH
- genetická variace MeSH
- genom MeSH
- jednonukleotidový polymorfismus MeSH
- molekulární evoluce MeSH
- populační genetika MeSH
- reprodukční izolace MeSH
- Spalax genetika fyziologie MeSH
- sympatrie * MeSH
- tok genů MeSH
- variabilita počtu kopií segmentů DNA MeSH
- vazebná nerovnováha MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Izrael MeSH
Accurate predictive modelling facilitates efficient and effective trait selection in animal breeding and can decrease costs while maximizing profits when raising economically important animals. The objective of this study was to extend a previously developed bioeconomic model and computer program to calculate the marginal economic values (MEVs) and economic weights (EWs) for direct and maternal pig traits affected by new reproductive traits, namely the number of sow functional teats (NFTs) and boar sperm quality traits (SQTs) that included sperm volume, sperm concentration, motility percentage and percentage of abnormal spermatozoa. The MEV of NFTs represented the cost differences between naturally and artificially reared piglets until weaning and the cost differences between naturally and artificially reared finished animals. The MEVs of SQTs expressed the saved costs for artificial insemination, assuming a decreased price per insemination dose when improving the SQTs. The absolute and relative EWs for the newly defined complex of traits in the breeding objectives for pig breeds involved in the Czech national three-way crossing system (Czech Large White [CLW], Czech Landrace [CL] and Pietrain [PN]) were calculated using gene flow methods. The NFT trait was included only for dam breeds, and the relative EW averaged 3.6% of the total economic importance based on the genetic standard deviations of all 19 simultaneously evaluated traits in CLW and CL breeds. The relative EWs of the four SQTs comprised 2.0% of the total economic importance of the 19 traits in the CLW and CL dam breeds and 8% of the total economic importance of the 18 traits in the PN sire breed. Therefore, inclusion of the NFTs for dam breeds and SQTs for sire breeds in the breeding goal is recommended to aid in obtaining ideal outcomes with optimal economic values.
- MeSH
- chov zvířat ekonomika MeSH
- chov ekonomika MeSH
- ekonomické modely MeSH
- fenotyp * MeSH
- mléčné žlázy zvířat * fyziologie MeSH
- prasata genetika fyziologie MeSH
- rozmnožování genetika MeSH
- selekce (genetika) MeSH
- spermie * fyziologie MeSH
- tok genů MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Species with vast production of dust-like windborne seeds, such as orchids, should not be limited by seed dispersal. This paradigm, however, does not fit recent studies showing that many sites suitable for orchids are unoccupied and most seeds land close to their maternal plant. To explore this issue, we studied seed dispersal and gene flow of two forest orchid species, Epipactis atrorubens and Cephalanthera rubra, growing in a fragmented landscape of forested limestone hills in southwest Bohemia, Czech Republic. We used a combination of seed trapping and plant genotyping methods (microsatellite DNA markers) to quantify short- and long-distance dispersal, respectively. In addition, seed production of both species was estimated. We found that most seeds landed very close to maternal plants (95% of captured seeds were within 7.2 m) in both species, and dispersal distance was influenced by forest type in E. atrorubens. In addition, C. rubra showed clonal reproduction (20% of plants were of clonal origin) and very low fruiting success (only 1.6% of plants were fruiting) in comparison with E. atrorubens (25.7%). Gene flow was frequent up to 2 km in C. rubra and up to 125 km in E. atrorubens, and we detected a relatively high dispersal rate among regions in both species. Although both species occupy similar habitats and have similar seed dispersal abilities, C. rubra is notably rarer in the study area. Considerably low fruiting success in this species likely limits its gene flow to longer distances and designates it more sensitive to habitat loss and fragmentation.
- MeSH
- ekosystém * MeSH
- Orchidaceae * genetika MeSH
- šíření semen * MeSH
- tok genů * MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Human population history in the Holocene was profoundly impacted by changes in lifestyle following the invention and adoption of food-production practices. These changes triggered significant increases in population sizes and expansions over large distances. Here we investigate the population history of the Fulani, a pastoral population extending throughout the African Sahel/Savannah belt. RESULTS: Based on genome-wide analyses we propose that ancestors of the Fulani population experienced admixture between a West African group and a group carrying both European and North African ancestries. This admixture was likely coupled with newly adopted herding practices, as it resulted in signatures of genetic adaptation in contemporary Fulani genomes, including the control element of the LCT gene enabling carriers to digest lactose throughout their lives. The lactase persistence (LP) trait in the Fulani is conferred by the presence of the allele T-13910, which is also present at high frequencies in Europe. We establish that the T-13910 LP allele in Fulani individuals analysed in this study lies on a European haplotype background thus excluding parallel convergent evolution. We furthermore directly link the T-13910 haplotype with the Lactase Persistence phenotype through a Genome Wide Association study (GWAS) and identify another genomic region in the vicinity of the SPRY2 gene associated with glycaemic measurements after lactose intake. CONCLUSIONS: Our findings suggest that Eurasian admixture and the European LP allele was introduced into the Fulani through contact with a North African population/s. We furthermore confirm the link between the lactose digestion phenotype in the Fulani to the MCM6/LCT locus by reporting the first GWAS of the lactase persistence trait. We also explored other signals of recent adaptation in the Fulani and identified additional candidates for selection to adapt to herding life-styles.
The X and Z sex chromosomes play a disproportionately large role in intrinsic postzygotic isolation. The underlying mechanisms of this large X/Z effect are, however, still poorly understood. Here we tested whether faster rates of molecular evolution caused by more intense positive selection or genetic drift on the Z chromosome could contribute to the large Z effect in two closely related passerine birds, the Common Nightingale (Luscinia megarhynchos) and the Thrush Nightingale (L. luscinia). We found that the two species differ in patterns of molecular evolution on the Z chromosome. The Z chromosome of L. megarhynchos showed lower levels of within-species polymorphism and an excess of non-synonymous polymorphisms relative to non-synonymous substitutions. This is consistent with increased levels of genetic drift on this chromosome and may be attributed to more intense postcopulatory sexual selection acting on L. megarhynchos males as was indicated by significantly longer sperm and higher between-male variation in sperm length in L. megarhynchos compared to L. luscinia. Interestingly, analysis of interspecific gene flow on the Z chromosome revealed relatively lower levels of introgression from L. megarhynchos to L. luscinia than vice versa, indicating that the Z chromosome of L. megarhynchos accumulated more hybrid incompatibilities. Our results are consistent with the view that postcopulatory sexual selection may reduce the effective population size of the Z chromosome and thus lead to stronger genetic drift on this chromosome in birds. This can result in relatively faster accumulation of hybrid incompatibilities on the Z and thus contribute to the large Z effect.
- MeSH
- druhová specificita MeSH
- genetická variace MeSH
- genetický drift MeSH
- molekulární evoluce MeSH
- pohlavní chromozomy genetika MeSH
- sexuální výběr u zvířat * MeSH
- spermie cytologie MeSH
- tok genů MeSH
- vznik druhů (genetika) MeSH
- zpěvní ptáci genetika fyziologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Müllerian mimicry rings are remarkable symbiotic species assemblages in which multiple members share a similar phenotype. However, their evolutionary origin remains poorly understood. Although gene flow among species has been shown to generate mimetic patterns in some Heliconius butterflies, mimicry is believed to be due to true convergence without gene flow in many other cases. We investigated the evolutionary history of multiple members of a passerine mimicry ring in the poisonous Papuan pitohuis. Previous phylogenetic evidence indicates that the aposematic coloration shared by many, but not all, members of this genus is ancestral and has only been retained by members of the mimicry ring. Using a newly assembled genome and thousands of genomic DNA markers, we demonstrate gene flow from the hooded pitohui (Pitohui dichrous) into the southern variable pitohui (Pitohui uropygialis), consistent with shared patterns of aposematic coloration. The vicinity of putatively introgressed loci is significantly enriched for genes that are important in melanin pigment expression and toxin resistance, suggesting that gene flow may have been instrumental in the sharing of plumage patterns and toxicity. These results indicate that interspecies gene flow may be a more general mechanism in generating mimicry rings than hitherto appreciated.
- MeSH
- biologická evoluce * MeSH
- druhová specificita MeSH
- fenotyp MeSH
- fylogeneze MeSH
- genom * MeSH
- jedovatá zvířata genetika MeSH
- pigmentace genetika MeSH
- proteiny genetika MeSH
- tok genů * MeSH
- zpěvní ptáci klasifikace genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The columbine genus Aquilegia is a classic example of an adaptive radiation, involving a wide variety of pollinators and habitats. Here we present the genome assembly of A. coerulea 'Goldsmith', complemented by high-coverage sequencing data from 10 wild species covering the world-wide distribution. Our analyses reveal extensive allele sharing among species and demonstrate that introgression and selection played a role in the Aquilegia radiation. We also present the remarkable discovery that the evolutionary history of an entire chromosome differs from that of the rest of the genome - a phenomenon that we do not fully understand, but which highlights the need to consider chromosomes in an evolutionary context.
- MeSH
- Aquilegia genetika MeSH
- biologická adaptace * MeSH
- chromozomy rostlin * MeSH
- distribuce rostlin MeSH
- genom rostlinný * MeSH
- molekulární evoluce * MeSH
- sekvenční analýza DNA MeSH
- selekce (genetika) MeSH
- tok genů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
