Although a growing number of both sequence-based and microsatellite nuclear loci have been used to infer genetic structures, their relative efficiencies remain poorly understood. In our study, we used the Green-backed...Although a growing number of both sequence-based and microsatellite nuclear loci have been used to infer genetic structures, their relative efficiencies remain poorly understood. In our study, we used the Green-backed Tit (Parus monticolus) to explore the resolving ability of these two types of markers. The south-western and central mitochondrial DNA (mtDNA) phylogroups were divergent to some extent in sequence-based nuclear data, while mixed together in microsatellites data. The F ST values among clades were about four times lower in microsatellite loci than those in sequence-based nuclear loci. We are of the opinion that size homoplasy may have contributed to the inability of microsatellites to uncover differentiation. Our results suggest that sequence-based nuclear loci outperformed microsatellite loci in detecting population structures, especially those focused on populations with large effective population sizes. There was no significant correlation between F ST values and allelic size variability, which suggested that the efficiency of microsatellite loci in detecting genetic structure may be independent of their polymorphism. F ST is better than R ST in detecting intraspecific divergence due to the high variance of R ST . In agreement with sequence-based nuclear loci, microsatellite loci did resolve the genetic distinctness of the Taiwan Residents phylogroup. The genetic differentiation between the Taiwan Residents and continental clades may involve allopatric divergence without gene flow.展开更多
Sexual selection is expected to promote speciation by fostering the evolution of sexual traits that minimize reproductive interactions among existing or incipient species. In species that compete for access to, or att...Sexual selection is expected to promote speciation by fostering the evolution of sexual traits that minimize reproductive interactions among existing or incipient species. In species that compete for access to, or attention of, females, sexual selec- tion fosters more elaborate traits in males compared to females. If these traits also minimize reproductive interactions with het- erospecifics, then species with enhanced risk of interactions between species might display greater numbers of these sexually di- morphic characters. We tested this prediction in eight families of North American birds. In particular, we evaluated whether the number of sexually dimorphic traits was positively associated with species richness at a given site or with degree of sympatry with congeners. We found no strong evidence of enhanced sexual dimorphism with increasing confamilial species richness at a given site. We also found no overall relationship between the number of sexually dimorphic traits and overlap with congeners across these eight families. However, we found patterns consistent with our prediction within Anatidae （ducks, geese and swans） and, to a lesser degree, Parulidae （New World warblers）. Our results suggest that sexually selected plumage traits in these groups potentially play a role in reproductive isolation [Current Zoology 58 （3）： 453--462, 2012].展开更多
基金supported by the National Science Fund for Distinguished Young Scientists (No. 30925008)the Major International (Regional) Joint Research Project (No. 31010103901)+1 种基金the CAS-IOZ Innovation Program (KSCX2-EW-J-2) by a grant (No. O529YX5105) from the Key Laboratory of the Zoological Systematics and Evolution of the Chinese Academy of Sciences to F.M. Lei
文摘Although a growing number of both sequence-based and microsatellite nuclear loci have been used to infer genetic structures, their relative efficiencies remain poorly understood. In our study, we used the Green-backed Tit (Parus monticolus) to explore the resolving ability of these two types of markers. The south-western and central mitochondrial DNA (mtDNA) phylogroups were divergent to some extent in sequence-based nuclear data, while mixed together in microsatellites data. The F ST values among clades were about four times lower in microsatellite loci than those in sequence-based nuclear loci. We are of the opinion that size homoplasy may have contributed to the inability of microsatellites to uncover differentiation. Our results suggest that sequence-based nuclear loci outperformed microsatellite loci in detecting population structures, especially those focused on populations with large effective population sizes. There was no significant correlation between F ST values and allelic size variability, which suggested that the efficiency of microsatellite loci in detecting genetic structure may be independent of their polymorphism. F ST is better than R ST in detecting intraspecific divergence due to the high variance of R ST . In agreement with sequence-based nuclear loci, microsatellite loci did resolve the genetic distinctness of the Taiwan Residents phylogroup. The genetic differentiation between the Taiwan Residents and continental clades may involve allopatric divergence without gene flow.
文摘Sexual selection is expected to promote speciation by fostering the evolution of sexual traits that minimize reproductive interactions among existing or incipient species. In species that compete for access to, or attention of, females, sexual selec- tion fosters more elaborate traits in males compared to females. If these traits also minimize reproductive interactions with het- erospecifics, then species with enhanced risk of interactions between species might display greater numbers of these sexually di- morphic characters. We tested this prediction in eight families of North American birds. In particular, we evaluated whether the number of sexually dimorphic traits was positively associated with species richness at a given site or with degree of sympatry with congeners. We found no strong evidence of enhanced sexual dimorphism with increasing confamilial species richness at a given site. We also found no overall relationship between the number of sexually dimorphic traits and overlap with congeners across these eight families. However, we found patterns consistent with our prediction within Anatidae （ducks, geese and swans） and, to a lesser degree, Parulidae （New World warblers）. Our results suggest that sexually selected plumage traits in these groups potentially play a role in reproductive isolation [Current Zoology 58 （3）： 453--462, 2012].
