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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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Related in: MedlinePlus

Maximum likelihood (ML) trees based on the control region (CR), ND4, ND5 and cyt b sequences. The best-scoring maximum likelihood tree from partitioned ML analyses based on the CR (a), ND4 (b), ND5 (c) and cyt b (d) sequences of mtDNA. Numbers above the internal branches indicate neighbour-joining and ML bootstrap (BS) values and Bayesian (BI) posterior probabilities. The BS and BI values are given only for the nodes of major clades. Haplotypes observed in triploids are shaded. Haplotypes shared between diploids and triploids are shown in italic and shaded. Clade numbers I - VII correspond to those given in the NJ tree (Figure 2).
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Figure 3: Maximum likelihood (ML) trees based on the control region (CR), ND4, ND5 and cyt b sequences. The best-scoring maximum likelihood tree from partitioned ML analyses based on the CR (a), ND4 (b), ND5 (c) and cyt b (d) sequences of mtDNA. Numbers above the internal branches indicate neighbour-joining and ML bootstrap (BS) values and Bayesian (BI) posterior probabilities. The BS and BI values are given only for the nodes of major clades. Haplotypes observed in triploids are shaded. Haplotypes shared between diploids and triploids are shown in italic and shaded. Clade numbers I - VII correspond to those given in the NJ tree (Figure 2).

Mentions: ML and BI trees based on the CR data showed an essentially similar haplotype grouping as that of the NJ tree (Figure 3a, only the ML tree is shown). However, the ML and BI tree topologies differed somewhat from that of the NJ tree; clade III detected in the NJ tree was not detected in the ML and BI trees.


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)

Maximum likelihood (ML) trees based on the control region (CR), ND4, ND5 and cyt b sequences. The best-scoring maximum likelihood tree from partitioned ML analyses based on the CR (a), ND4 (b), ND5 (c) and cyt b (d) sequences of mtDNA. Numbers above the internal branches indicate neighbour-joining and ML bootstrap (BS) values and Bayesian (BI) posterior probabilities. The BS and BI values are given only for the nodes of major clades. Haplotypes observed in triploids are shaded. Haplotypes shared between diploids and triploids are shown in italic and shaded. Clade numbers I - VII correspond to those given in the NJ tree (Figure 2).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Maximum likelihood (ML) trees based on the control region (CR), ND4, ND5 and cyt b sequences. The best-scoring maximum likelihood tree from partitioned ML analyses based on the CR (a), ND4 (b), ND5 (c) and cyt b (d) sequences of mtDNA. Numbers above the internal branches indicate neighbour-joining and ML bootstrap (BS) values and Bayesian (BI) posterior probabilities. The BS and BI values are given only for the nodes of major clades. Haplotypes observed in triploids are shaded. Haplotypes shared between diploids and triploids are shown in italic and shaded. Clade numbers I - VII correspond to those given in the NJ tree (Figure 2).
Mentions: ML and BI trees based on the CR data showed an essentially similar haplotype grouping as that of the NJ tree (Figure 3a, only the ML tree is shown). However, the ML and BI tree topologies differed somewhat from that of the NJ tree; clade III detected in the NJ tree was not detected in the ML and BI trees.

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