Gymnocypris Eckloni Research Articles

Genetic diversity and taxonomic status of Gymnocypris chilianensis based on the mitochondrial DNA cytochrome b gene.

In order to study the genetic diversity and taxonomic status of Gymnocypris chilianensis on a molecular level, the mitochondrial DNA cytochrome b gene was sequenced for 74 individuals of G. chilianensis from two locations (Heihe River and Shule River) and 42 individuals of its affinis species Gymnocypris przewalskii. Analyses of genetic diversity and sequence differences were conducted for these samples, combined with the analysis of 30 homologous sequences of another affinis species Gymnocypris eckloni, which were downloaded from GenBank. The results showed that both the haplotype diversity (h = 0.9820) and nucleotide diversity (π= 0.0039) of the Shule River G. chilianensis were lower than the other populations, thus, the Shule River G. chilianensis should be prioritized for protection because of its lower genetic diversity level. The results of sequence analysis showed that the genetic distance between the Heihe River G. chilianensis population and the Shule River G. chilianensis population was 0.0064, and the genetic distance between these two populations and the G. przewalskii population was 0.0838 and 0.0810, respectively. The genetic distance between the two G. chilianensis populations and the G. eckloni population was 0.0805 and 0.0778, respectively. Analysis of sequence differences indicates that G. chilianensis is sufficiently diverged from G. przewalskii and G. eckloni to the extent that it has reached species level, thus, G. chilianensis can be considered an independent species of Gymnocypris.

Complete mitochondrial genomes of two relatively closed species from Gymnocypris (Cypriniformes: Cyprinidae): Genome characterization and phylogenetic considerations

The complete mitochondrial genome for Gymnocypris eckloni and Gymnocypris przewalskii ganzihonensis is 16,686 and 16,682 bp in size, respectively. Both of the mitochondrial genomes have identical genomic organization and structure including 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes and 1 control region as found in other vertebrates, with the exception of 86 bp non-coding nucleotides between tRNAThr and tRNAPro. The phylogenetic analyses based on the concatenated nucleotide sequence of 12 PCGs on the heavy strand supported a relatively closed relationship among G. eckloni, G. p. przewalskii and G. p. ganzihonensis. The sequence divergence between G. eckloni and G. przewalskii, as well as within G. przewalskii, is relatively low compared to the average sequence divergence among other cyprinid fishes, suggesting that they are the most closely related species resulted from a relatively recent speciation event. The estimated molecular divergence time is coincided with a relatively recent speciation event occurring during the separation of the Yellow River and Qinghai Lake.

Phylogeography and conservation genetics of Lake Qinghai scaleless carp Gymnocypris przewalskii

The objective of this study was to examine the spatial genetic relationships of the Lake Qinghai scaleless carp Gymnocypris przewalskii within the Lake Qinghai system, determining whether genetic evidence supports the current taxonomy of Gymnocypris przewalskii przewalskii and Gymnocypris przewalskii ganzihonensis and whether Gymnocypris przewalskii przewalskii are returning to their natal rivers to spawn. Comparison of mitochondrial (control region) variation (42 haplotypes in 203 fish) of G. przewalskii with the postulated ancestral species found in the Yellow River, Gymnocypris eckloni (10 haplotypes in 23 fish), indicated no haplotype sharing, but incomplete lineage sorting. Consistent with the sub-species status, an AMOVA indicated that the Ganzi River population was significantly different from all other river populations (F(ST) = 0·1671, P < 0·001). No genetic structure was found among the other rivers in the Lake Qinghai catchment. An AMOVA of amplified fragment length polymorphism (AFLP) loci, however, revealed significant genetic differences between most spawning populations (F(ST) = 0·0721, P < 0·001). Both mitochondrial and AFLP data found significant differences among G. p. przewalskii, G. p. ganzihonensis and G. eckloni (F(ST) values of 0·1959 and 0·1431, respectively, P < 0·001). Consistent with the incomplete lineage sorting, Structure analysis of AFLP loci showed evidence of five clusters. One cluster is shared among all sample locations, one is unique to G. p. ganzihonensis and G. eckloni, and the others are mostly found in G. p. przewalskii. Genetic evidence therefore supports the current taxonomy, including the sub-species status of G. p. ganzihonensis, and is consistent with natal homing of most Lake Qinghai populations. These findings have significant implications for the conservation and management of this unique and threatened species. The evidence suggests that G. p. przewalskii should be treated as a single population for conservation purposes. Exchangeability of the populations, however, should not be used to promote homogenization of fish spawning in the different rivers. As some degree of genetic divergence was detected in this study, it is recommended that the spawning groups be treated as separate management units.

Molecular phylogenetics of Gymnocypris (Teleostei: Cy-prinidae) in Lake Qinghai and adjacent drainages

149 complete mitochondrial DNA (mtDNA) cytochrome b (Cyt b) genes (1140 bp) of Gymnocypris przewalskii, Gymnocypris eckloni and Gymnocyptis scolistomus from the Lake Qinghai, Yellow River and Qaidam Basin were sequenced and analyzed. Consistent dendrogram indicated that the samples collected from the same species do not constitute a separate monophyletic group and all the samples were grouped into three highly divergent lineages (A, B and C). Among them, Lineage A contained all samples of G. przewalskii from the Lake Qinghai and partial samples of the G. eckloni from the Yellow River. Lineage B contained the remaining samples of G. eckloni from the Yellow River. Lineage C was composed of a monophyletic group by G. eckloni from the Qaidam Basin. Analysis of molecular variance (AMOVA) indicated that most of genetic variations were detected within these three mtDNA lineages (93.12%), suggesting that there are three different lineages of Gymnocypris in this region. Our Cyt b sequence data showed that G. przewalskii was not a polytypic species, and G. scolistomus was neither an independent species nor a subspecies of G. eckloni. The divergent mtDNA lineages of G. eckloni from the Yellow River suggested that gene flow between the different populations was restricted to a certain extent by several gorges on the upper reach of the Yellow River. Lineage B of G. eckloni might be the genetic effect from the ancestor which was incorporated with the endemic schizothoracine fishes when the headward erosion of the Yellow River reached to its current headwaters of late. The G. eckloni from Basin Qaidam was a monophyletic group (lineage C) and F-st values within G. eckloni from the Yellow River were higher than 0.98, suggesting that the gene flow has been interrupted for a long time and the G. eckloni from Basin Qaidam might have been evolved into different species by ecology segregation. The correlation between the rakers number of Gymnocypris and population genetic variation was not significant. All Gymnocypris populations exhibited a low nucleotide diversity (pi = 0.00096-0.00485). Therefore the Gymnocyptis populations from Basin Qaidam could have experienced severe bottleneck effect in history. Our result suggested Gym-nocypris populations of Basin Qaidam should give a high priority in conservation programs.