Chakouyi(CKY)horses from the Qinghai-Xizang Plateau are well known for their unique lateral gaits and high-altitude adaptation,but genetic mechanisms underlying these phenotypes remain unclear.This study presents a co...Chakouyi(CKY)horses from the Qinghai-Xizang Plateau are well known for their unique lateral gaits and high-altitude adaptation,but genetic mechanisms underlying these phenotypes remain unclear.This study presents a comparison of 60 newly resequenced genomes of gaited CKY horses with 139 public genomes from 19 horse breeds.Population structure analyses(admixture,PCA,and neighbor-joining tree)reveal a close genetic relationship between CKY and other highland breeds(Tibetan and Chaidamu horses).Compared with other Chinese breeds,CKY horses present reduced nucleotide diversity(θπ)and lower inbreeding(FROHcoefficient),suggesting possible selective pressures.A key region on chromosome 23(Chr23:22.3-22.6 Mb)is associated with the lateral gaits and harbors a highly prevalent nonsense mutation(Chr 23:22,391,254 C>A,Ser301STOP)in the DMRT3 gene,with an 88%homozygosity rate,which is strongly correlated with the distinctive gait of CKY horses.Furthermore,selection signals reveal that the EPAS1 gene is related to high-altitude adaptation,and the CAT gene contributes to altitude resilience in CKY horses.These findings suggest that preserving genetic diversity is essential for maintaining the unique gaits and high-altitude adaptations of CKY horses.展开更多
The realization that body parts of animals and plants can be recruited or coopted for novel functions dates back to, or even predates the observations of Darwin. S.J. Gould and E.S. Vrba recognized a mode of evolution...The realization that body parts of animals and plants can be recruited or coopted for novel functions dates back to, or even predates the observations of Darwin. S.J. Gould and E.S. Vrba recognized a mode of evolution of characters that differs from adaptation. The umbrella term aptation was supplemented with the concept of exaptation. Unlike adaptations, which are restricted to features built by selection for their current role, exaptations are features that currently enhance fitness, even though their present role was not a result of natural selection. Exaptations can also arise from nonaptations; these are characters which had previously been evolving neutrally. All nonaptations are potential exaptations. The concept of exaptation was expanded to the molecular genetic level which aided greatly in understanding the enormous potential of neutrally evolving repetitive DNA—including transposed elements, formerly considered junk DNA—for the evolution of genes and genomes. The distinction between adaptations and exaptations is outlined in this review and examples are given. Also elaborated on is the fact that such distinctions are sometimes more difficult to determine; this is a widespread phenomenon in biology, where continua abound and clear borders between states and definitions are rare.展开更多
基金the members of the Extending Station for Animal Husbandry and Veterinary Technology of Tianzhu Xizang Autonomous County for their help in sample collection and data acquisition.This research was supported by the Supercomputing Center of Lanzhou University and the Chakouyi horse conservation project from the Tianzhu Xizang Autonomous County Government([20]0097).
文摘Chakouyi(CKY)horses from the Qinghai-Xizang Plateau are well known for their unique lateral gaits and high-altitude adaptation,but genetic mechanisms underlying these phenotypes remain unclear.This study presents a comparison of 60 newly resequenced genomes of gaited CKY horses with 139 public genomes from 19 horse breeds.Population structure analyses(admixture,PCA,and neighbor-joining tree)reveal a close genetic relationship between CKY and other highland breeds(Tibetan and Chaidamu horses).Compared with other Chinese breeds,CKY horses present reduced nucleotide diversity(θπ)and lower inbreeding(FROHcoefficient),suggesting possible selective pressures.A key region on chromosome 23(Chr23:22.3-22.6 Mb)is associated with the lateral gaits and harbors a highly prevalent nonsense mutation(Chr 23:22,391,254 C>A,Ser301STOP)in the DMRT3 gene,with an 88%homozygosity rate,which is strongly correlated with the distinctive gait of CKY horses.Furthermore,selection signals reveal that the EPAS1 gene is related to high-altitude adaptation,and the CAT gene contributes to altitude resilience in CKY horses.These findings suggest that preserving genetic diversity is essential for maintaining the unique gaits and high-altitude adaptations of CKY horses.
文摘The realization that body parts of animals and plants can be recruited or coopted for novel functions dates back to, or even predates the observations of Darwin. S.J. Gould and E.S. Vrba recognized a mode of evolution of characters that differs from adaptation. The umbrella term aptation was supplemented with the concept of exaptation. Unlike adaptations, which are restricted to features built by selection for their current role, exaptations are features that currently enhance fitness, even though their present role was not a result of natural selection. Exaptations can also arise from nonaptations; these are characters which had previously been evolving neutrally. All nonaptations are potential exaptations. The concept of exaptation was expanded to the molecular genetic level which aided greatly in understanding the enormous potential of neutrally evolving repetitive DNA—including transposed elements, formerly considered junk DNA—for the evolution of genes and genomes. The distinction between adaptations and exaptations is outlined in this review and examples are given. Also elaborated on is the fact that such distinctions are sometimes more difficult to determine; this is a widespread phenomenon in biology, where continua abound and clear borders between states and definitions are rare.
