What kind of genetic variation contributes the most to adaptation is a fundamental question in evolutionary biology. By resequencing genomes of 80 individuals, we inferred the origin of genomic ...variants associated with a complex adaptive syndrome involving multiple quantitative traits, namely, adaptation between high and low altitudes, in the vinous-throated parrotbill (Sinosuthora webbiana) in Taiwan. By comparing these variants with those in the Asian mainland population, we revealed standing variation in 24 noncoding genomic regions to be the predominant genetic source of adaptation. Parrotbills at both high and low altitudes exhibited signatures of recent selection, suggesting that not only the front but also the trailing edges of postglacial expanding populations could be subjected to environmental stresses. This study verifies and quantifies the importance of standing variation in adaptation in a cohort of genes, illustrating that the evolutionary potential of a population depends significantly on its preexisting genetic diversity. These findings provide important context for understanding adaptation and conservation of species in the Anthropocene.
We report the sequencing at 131× coverage, de novo assembly and analyses of the genome of a female Tibetan wild boar. We also resequenced the whole genomes of 30 Tibetan wild boars from six major ...distributed locations and 18 geographically related pigs in China. We characterized genetic diversity, population structure and patterns of evolution. We searched for genomic regions under selection, which includes genes that are involved in hypoxia, olfaction, energy metabolism and drug response. Comparing the genome of Tibetan wild boar with those of neighboring Chinese domestic pigs further showed the impact of thousands of years of artificial selection and different signatures of selection in wild boar and domestic pig. We also report genetic adaptations in Tibetan wild boar that are associated with high altitudes and characterize the genetic basis of increased salivation in domestic pig.
Wild relatives of crops are an important source of genetic diversity for agriculture, but their gene repertoire remains largely unexplored. We report the establishment and analysis of a pan-genome of ...Glycine soja, the wild relative of cultivated soybean Glycine max, by sequencing and de novo assembly of seven phylogenetically and geographically representative accessions. Intergenomic comparisons identified lineage-specific genes and genes with copy number variation or large-effect mutations, some of which show evidence of positive selection and may contribute to variation of agronomic traits such as biotic resistance, seed composition, flowering and maturity time, organ size and final biomass. Approximately 80% of the pan-genome was present in all seven accessions (core), whereas the rest was dispensable and exhibited greater variation than the core genome, perhaps reflecting a role in adaptation to diverse environments. This work will facilitate the harnessing of untapped genetic diversity from wild soybean for enhancement of elite cultivars.
Uncovering genetic variation through resequencing is limited by the fact that only sequences with similarity to the reference genome are examined. Reference genomes are often incomplete and cannot ...represent the full range of genetic diversity as a result of geographical divergence and independent demographic events. To more comprehensively characterize genetic variation of pigs (
), we generated de novo assemblies of nine geographically and phenotypically representative pigs from Eurasia. By comparing them to the reference pig assembly, we uncovered a substantial number of novel SNPs and structural variants, as well as 137.02-Mb sequences harboring 1737 protein-coding genes that were absent in the reference assembly, revealing variants left by selection. Our results illustrate the power of whole-genome de novo sequencing relative to resequencing and provide valuable genetic resources that enable effective use of pigs in both agricultural production and biomedical research.
Pleistocene climate fluctuations shaped the patterns of genetic diversity observed in extant species. In contrast to Europe and North America where the effects of recent glacial cycles on genetic ...diversity have been well studied, the genetic legacy of the Late Pleistocene for East Asia, a region of great topographical complexity and presumably milder historical climate, remains poorly understood. We analysed 3.86 kb of the mitochondrial genome of 186 Chinese Hwamei birds, Leucodioptron canorum canorum, and found that contrary to the conventional expectation of population decline during cold periods (stadials), the demographic history of this species shows continuous population growth since the penultimate glacial period (about 170 000 years ago). Refugia were identified in the south, coastal regions, and northern inland areas, implying that topographic complexity played a substantial role in providing suitable habitats for the Chinese Hwamei during cold periods. Intermittent gene flow between these refugia during the warmer periods (interstadials) might have resulted in a large effective population of this bird through the last glacial period.
Domesticated organisms have experienced strong selective pressures directed at genes or genomic regions controlling traits of biological, agricultural or medical importance. The genome of native and ...domesticated pigs provide a unique opportunity for tracing the history of domestication and identifying signatures of artificial selection. Here we used whole-genome sequencing to explore the genetic relationships among the European native pig Berkshire and breeds that are distributed worldwide, and to identify genomic footprints left by selection during the domestication of Berkshire. Numerous nonsynonymous SNPs-containing genes fall into olfactory-related categories, which are part of a rapidly evolving superfamily in the mammalian genome. Phylogenetic analyses revealed a deep phylogenetic split between European and Asian pigs rather than between domestic and wild pigs. Admixture analysis exhibited higher portion of Chinese genetic material for the Berkshire pigs, which is consistent with the historical record regarding its origin. Selective sweep analyses revealed strong signatures of selection affecting genomic regions that harbor genes underlying economic traits such as disease resistance, pork yield, fertility, tameness and body length. These discoveries confirmed the history of origin of Berkshire pig by genome-wide analysis and illustrate how domestication has shaped the patterns of genetic variation.
The long‐term persistence of a population which has suffered a bottleneck partly depends on how historical demographic dynamics impacted its genetic diversity and the accumulation of deleterious ...mutations. Here we provide genomic evidence for the genetic effect of a recent population bottleneck in the endangered black‐faced spoonbill (Platalea minor) after its rapid population recovery. Our data suggest that the bird's effective population size, Ne, had been relatively stable (7500–9000) since 22,000 years ago; however, a recent brief yet severe bottleneck (Ne = 20) which we here estimated to occur around the 1940s wiped out >99% of its historical Ne in roughly three generations. Despite a >15‐fold population recovery since 1988, we found that black‐faced spoonbill population has higher levels of inbreeding (7.4 times more runs of homozygosity) than its sister species, the royal spoonbill (P. regia), which is not thought to have undergone a marked population contraction. Although the two spoonbills have similar levels of genome‐wide genetic diversity, our results suggest that selection on more genes was relaxed in the black‐faced spoonbill; moreover individual black‐faced spoonbills carry more putatively deleterious mutations (Grantham's score > 50), and may therefore express more deleterious phenotypic effects than royal spoonbills. Here we demonstrate the value of using genomic indices to monitor levels of genetic erosion, inbreeding and mutation load in species with conservation concerns. To mitigate the prolonged negative genetic effect of a population bottleneck, we recommend that all possible measures should be employed to maintain population growth of a threatened species.
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► Most comprehensive phylogenetic frameworks of parrotbills in terms of taxa and gene sampling. ► Incongruent mitochondrial and nuclear phylogenies caution against single marker-based ...phylogenetic inferences. ► Phylogenies help evaluate taxonomic hypotheses and outline numerous topics for further evolutionary studies.
The parrotbills (Paradoxornithidae, meaning “birds of paradox,” Aves) are a group of Old World passerines with perplexing taxonomic histories due to substantial morphological and ecological variation at various levels. In this study, phylogenetic relationships of the parrotbills were reconstructed based on sequences of two mitochondrial segments and three nuclear coding regions. Three major clades with characteristic body size and plumage coloration were found in both mtDNA and nuclear gene trees. However, mtDNA phylogeny suggested that the Paradoxornithidae is paraphyletic and relationships among three major parrotbill clades were poorly resolved. On the contrary, apparent and well-supported monophyletic relationships among the three major clades of Paradoxornithidae were revealed by concatenated nuclear dataset. Since paraphyly based on mtDNA data has commonly been found within avian taxa, the conflicting phylogenetic signal between mtDNA and nuclear loci revealed in this study indicates that results obtained from mtDNA dataset alone need to be evaluated with caution. Taxonomic implications of our phylogenetic findings are discussed. These phylogenies also point out areas for future investigation regarding the rapid diversification, morphological evolution and environmental adaptation of various parrotbill species or species complexes.
Ecogeographic rules that describe quantitative relationships between morphologies and climate might help us predict how morphometrics of animals was shaped by local temperature or humidity. Although ...the ecogeographic rules had been widely tested in animals of Europe and North America, they had not been fully validated for species in regions that are less studied. Here, we investigate the morphometric variation of a widely distributed East Asian passerine, the vinous‐throated parrotbill (Sinosuthora webbiana), to test whether its morphological variation conforms to the prediction of Bergmann's rule, Allen's rules, and Gloger's rule. We at first described the climatic niche of S. webbiana from occurrence records (n = 7838) and specimen records (n = 290). The results of analysis of covariance (ANCOVA) suggested that the plumage coloration of these parrotbills was darker in wetter/warmer environments following Gloger's rule. However, their appendage size (culmen length, beak volume, tarsi length) was larger in colder environments, the opposite of the predictions of Allen's rule. Similarly, their body size (wing length) was larger in warmer environments, the opposite of the predictions of Bergmann's rule. Such disconformity to both Bergmann's rule and Allen's rule suggests that the evolution of morphological variations is likely governed by multiple selection forces rather than dominated by thermoregulation. Our results suggest that these ecogeographic rules should be validated prior to forecasting biological responses to climate change especially for species in less‐studied regions.
The morphometric variations of the vinous‐throated parrotbill (Sinosuthora webbiana) are not conform to predictions of Bergmann’s and Allen’s rules. This figure shows the positive relationships between temperature variables (bio1 and bio5) and wing length which against the prediction of Bergmann’s rule. Also, the negative relationships between temperature variables (bio1 and bio6) and beak size do not match the prediction of Allen’s rule.
Although species specificity between fig trees and their pollinators has been considered a classic example of obligate mutualism, increasing exceptions to the one-to-one relationship suggest that ...multiple pollinator species per fig host species may be a pervasive phenomenon. Based on both mitochondrial DNA and microsatellite analyses, we found three putative pollinator species (Ceratosolen spp.) associated with Ficus spetica in southern Taiwan, two of which, that differ in color, routinely coexist within single figs. These three pollinators are substantially divergent from the pollinator of F. spetica in New Guinea, implying that wasp diversity may be highly underestimated when the one-to-one rule is assumed. Our findings not only provide the first case of coexistence of pollinators within single figs on a shared dioecious Ficus host, but also an ideal system to investigate interspecific competition and sex allocation, especially when coexisting pollinators are visually distinguishable by their colors. Abstract in Chinese is available at http://www.blackwell-synergy.com/loi/btp.
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