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

Abstract

BackgroundCarassius 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.ResultsWe 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.ConclusionsThe 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.

High male incidence and evolutionary implications of triploid form in northeast Asia Carassius auratus complex

“…A fragment of mtDNA including partial tRNA-Pro gene, complete tRNA-Thr gene and the first third of control region was amplified by polymerase chain reaction (PCR) with the primer pair L15923 c and H16500 d (Takada et al, 2010) as described previously (Li and Gui, 2008). The amplified mtDNA fragments (described as CR for short) were purified by 1.0% lowmelting agarose gel electrophoresis, and sequenced from both sides with the same primer pair through an ABI PRISM 3700 sequencing system.…”

“…Carassius auratus complex has been generally thought to consist of both diploid form and triploid form that cannot be discriminated morphologically from each other (Apalikova et al, 2011;Gui and Zhou, 2010;Jakovlić and Gui, 2011;Takada et al, 2010), even though tetraploidization has been demonstrated to occur in the diploid form with 100 chromosomes (Ohno et al, 1967), and evolutionary hexaploid has been also suggested for the triploid form with more than 150 chromosomes (Zhou and Gui, 2002;Zhu et al, 2006). According to the current taxonomic category, the triploid form, also commonly known as gibel carp, silver crucian carp or Prussian carp, has been recognized as a subspecies gibel carp Carassius auratus gibelio (Cherfas, 1981;Jiang et al, 1983) of Carassius auratus, including the domestic goldfish, or even a separate species Carassius gibelio (Kalous et al, 2007;Kalous and Martin, 2011;Rylková et al, 2010).…”

Evolutionary history of two divergent Dmrt1 genes reveals two rounds of polyploidy origins in gibel carp

“…It has been observed widely in many countries of the Eurasian continent (Gui and Zhou, 2010), such as in Britain (Hanfling et al, 2005), Italy (Hanfling et al, 2005), Hungary (Toth et al, 2005), Germany (Hanfling et al, 2005), Croatia (Jakovlic and Gui, 2011), Greece (Liasko et al, 2010), Kazakhstan (Sakai et al, 2009), Russia (Abramenko et al, 2004;Jiang et al, 2013), China (Gao et al, 2012;Jiang et al, 2013;Li and Gui, 2008), and Japan (Takada et al, 2010). Similar to other unisexual polyploid vertebrates, the polyploid gibel carp can reproduce by spermdependent gynogenesis, and many diverse gynogenetic clones have been discriminated by biological traits and molecular markers (Bai et al, 2011;Gui and Zhou, 2010;Guo and Gui, 2008;Yang and Gui, 2004;Zhou et al, 2000a).…”

Recent invasion and low level of divergence between diploid and triploid forms of Carassius auratus complex in Croatia

“…Previously, phylogeographic studies of wild CAC populations have mostly been performed in the native range (Ohara et al 2003;Mezhzherin and Lisetskii 2004;Brykov et al 2005;Takada et al 2010). Except for a relatively remote Azov basin (Abramenko et al 2004) and some Greek populations (Tsipas et al 2009), no detailed study of European populations has ever been conducted.…”