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Biogeography and evolution of the Carassius auratus-complex in East Asia.

Takada M, Tachihara K, Kon T, Yamamoto G, Iguchi K, Miya M, Nishida M - BMC Evol. Biol. (2010)

Bottom Line: Triploids of C. auratus did not form a monophyletic lineage but were clustered mostly with sympatric diploids.The results of the present study revealed the existence of two superlineages of C. auratus in East Asia that include seven lineages endemic to each of the seven regions examined.An overall phylogenetic framework obtained from the present study will be of use for estimating the phylogenetic relationships of Carassius fishes on the Eurasian continent.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Fisheries Biology & Coral Reef Studies, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan. takada@ori.u-tokyo.ac.jp

ABSTRACT

Background: Carassius auratus is a primary freshwater fish with bisexual diploid and unisexual gynogenetic triploid lineages. It is distributed widely in Eurasia and is especially common in East Asia. Although several genetic studies have been conducted on C. auratus, they have not provided clear phylogenetic and evolutionary descriptions of this fish, probably due to selection bias in sampling sites and the DNA regions analysed. As the first step in clarifying the evolutionary entity of the world's Carassius fishes, we attempted to clarify the phylogeny of C. auratus populations distributed in East Asia.

Results: We conducted a detailed analysis of a large dataset of mitochondrial gene sequences [CR, 323 bp, 672 sequences (528 sequenced + 144 downloaded); CR + ND4 + ND5 + cyt b, 4669 bp in total, 53 sequences] obtained from C. auratus in East Asia. Our phylogeographic analysis revealed two superlineages, one distributed mainly among the Japanese main islands and the other in various regions in and around the Eurasian continent, including the Ryukyus and Taiwan. The two superlineages include seven lineages with high regional specificity that are composed of endemic populations indigenous to each region. The divergence time of the seven lineages was estimated to be 0.2 million years ago (Mya) by a fossil-based method and 1.0-1.9 Mya by the molecular clock method. The antiquity and endemism of these lineages suggest that they are native to their respective regions, although some seem to have been affected by the artificial introduction of C. auratus belonging to other lineages. Triploids of C. auratus did not form a monophyletic lineage but were clustered mostly with sympatric diploids.

Conclusions: The results of the present study revealed the existence of two superlineages of C. auratus in East Asia that include seven lineages endemic to each of the seven regions examined. The lack of substantial genetic separation between triploids and diploids indicates that triploids are not composed of a single independent lineage. The ancient origins and evolutionary uniqueness of the seven lineages warrant their conservation. An overall phylogenetic framework obtained from the present study will be of use for estimating the phylogenetic relationships of Carassius fishes on the Eurasian continent.

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Global geographical distribution of seven major lineages. Geographical distributions of haplotypes of the seven major lineages found in the present phylogenetic analyses and supermatrix analysis. Number in each pie graph denotes the number of sequences examined in the supermatrix analysis.
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Figure 7: Global geographical distribution of seven major lineages. Geographical distributions of haplotypes of the seven major lineages found in the present phylogenetic analyses and supermatrix analysis. Number in each pie graph denotes the number of sequences examined in the supermatrix analysis.

Mentions: All haplotypes other than those of clade V in European C. auratus were nested in Japanese native lineages (clades I and II). These clade I and II haplotypes were found only from the Czech Republic and Greece on the Eurasian continent, whereas clade I and II haplotypes were predominant in the Japanese main islands (Figure 7). This distributional disjunction leads to the hypothesis that European fish with these haplotypes originated via artificial introduction(s) from Japan. Artificial introduction of Carassius fishes has been a problem in the European region [46-50], and release of ornamental goldfish into natural waters is considered to be one of the primary causes of dispersion of non-native C. auratus. However, European C. auratus included in the present study may not have been derived from the release of ornamental goldfish because the goldfish is clearly a member of the Chinese C. auratus (clade VII) and has diverged greatly from specimens of clade I, II, and V haplotypes (Figures 2 and 6, and also see Komiyama et al. [2]). Much more sequence data for C. auratus collected throughout Eurasia is needed for more detailed phylogenetic and evolutionary pictures of the C. auratus-complex.


Biogeography and evolution of the Carassius auratus-complex in East Asia.

Takada M, Tachihara K, Kon T, Yamamoto G, Iguchi K, Miya M, Nishida M - BMC Evol. Biol. (2010)

Global geographical distribution of seven major lineages. Geographical distributions of haplotypes of the seven major lineages found in the present phylogenetic analyses and supermatrix analysis. Number in each pie graph denotes the number of sequences examined in the supermatrix analysis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2820001&req=5

Figure 7: Global geographical distribution of seven major lineages. Geographical distributions of haplotypes of the seven major lineages found in the present phylogenetic analyses and supermatrix analysis. Number in each pie graph denotes the number of sequences examined in the supermatrix analysis.
Mentions: All haplotypes other than those of clade V in European C. auratus were nested in Japanese native lineages (clades I and II). These clade I and II haplotypes were found only from the Czech Republic and Greece on the Eurasian continent, whereas clade I and II haplotypes were predominant in the Japanese main islands (Figure 7). This distributional disjunction leads to the hypothesis that European fish with these haplotypes originated via artificial introduction(s) from Japan. Artificial introduction of Carassius fishes has been a problem in the European region [46-50], and release of ornamental goldfish into natural waters is considered to be one of the primary causes of dispersion of non-native C. auratus. However, European C. auratus included in the present study may not have been derived from the release of ornamental goldfish because the goldfish is clearly a member of the Chinese C. auratus (clade VII) and has diverged greatly from specimens of clade I, II, and V haplotypes (Figures 2 and 6, and also see Komiyama et al. [2]). Much more sequence data for C. auratus collected throughout Eurasia is needed for more detailed phylogenetic and evolutionary pictures of the C. auratus-complex.

Bottom Line: Triploids of C. auratus did not form a monophyletic lineage but were clustered mostly with sympatric diploids.The results of the present study revealed the existence of two superlineages of C. auratus in East Asia that include seven lineages endemic to each of the seven regions examined.An overall phylogenetic framework obtained from the present study will be of use for estimating the phylogenetic relationships of Carassius fishes on the Eurasian continent.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Fisheries Biology & Coral Reef Studies, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan. takada@ori.u-tokyo.ac.jp

ABSTRACT

Background: Carassius auratus is a primary freshwater fish with bisexual diploid and unisexual gynogenetic triploid lineages. It is distributed widely in Eurasia and is especially common in East Asia. Although several genetic studies have been conducted on C. auratus, they have not provided clear phylogenetic and evolutionary descriptions of this fish, probably due to selection bias in sampling sites and the DNA regions analysed. As the first step in clarifying the evolutionary entity of the world's Carassius fishes, we attempted to clarify the phylogeny of C. auratus populations distributed in East Asia.

Results: We conducted a detailed analysis of a large dataset of mitochondrial gene sequences [CR, 323 bp, 672 sequences (528 sequenced + 144 downloaded); CR + ND4 + ND5 + cyt b, 4669 bp in total, 53 sequences] obtained from C. auratus in East Asia. Our phylogeographic analysis revealed two superlineages, one distributed mainly among the Japanese main islands and the other in various regions in and around the Eurasian continent, including the Ryukyus and Taiwan. The two superlineages include seven lineages with high regional specificity that are composed of endemic populations indigenous to each region. The divergence time of the seven lineages was estimated to be 0.2 million years ago (Mya) by a fossil-based method and 1.0-1.9 Mya by the molecular clock method. The antiquity and endemism of these lineages suggest that they are native to their respective regions, although some seem to have been affected by the artificial introduction of C. auratus belonging to other lineages. Triploids of C. auratus did not form a monophyletic lineage but were clustered mostly with sympatric diploids.

Conclusions: The results of the present study revealed the existence of two superlineages of C. auratus in East Asia that include seven lineages endemic to each of the seven regions examined. The lack of substantial genetic separation between triploids and diploids indicates that triploids are not composed of a single independent lineage. The ancient origins and evolutionary uniqueness of the seven lineages warrant their conservation. An overall phylogenetic framework obtained from the present study will be of use for estimating the phylogenetic relationships of Carassius fishes on the Eurasian continent.

Show MeSH
Related in: MedlinePlus