Polyploid-specific repetitive DNA sequences from triploid ginbuna (Japanese silver crucian carp, Carassius auratus langsdorfi).

Abstract

Repetitive DNA sequences (Cal3nDr) in the genome of a triploid ginbuna (Carassius auratus langsdorfi) were isolated from the DraI digests of the genomic DNA. This AT-rich (61%) Cal3nDr monomer was 137 bp in length. The nucleotide similarity among the monomers from the same individual was considerably high (above 97%). Hybridization analyses revealed that the Cal3nDr sequences were organized into tandem arrays. These DNA sequences were present only in triploid and tetraploid ginbunas and were absent from diploid ginbuna, gengorobuna, goldfish, and other cyprinid fishes, and therefore appeared to be specific to polyploid ginbunas. In situ hybridization data showed their localization on one to four out of a total of 150 to 156 chromosomes, depending on the individuals or clonal lines, of the triploid ginbuna. The origin of the Cal3nDr sequences is also discussed on the basis of observation of the artificial triploid ginbuna produced by crossing a diploid female with a tetraploid male.

The maternal origins of the triploid ginbuna(Carassius auratus langsdorfi): Phylogenetic relationships within the C. auratus taxa by partial mitochondrial D-loop sequencing.

“…The triploid ginbuna is also considered to have originated from hybridizations on the basis of electrophoretic polymorphism of isozymes (Shimizu et al, 1993). Although our previous molecular data on the repetitive DNA sequences (Cal3nDr) supported the hybrid origin of the polyploid ginbuna (Murakami and Fujitani, 1997), its ancestral parents have not been defined yet. Thus, both the phylogenetic position of the gynogenetic triploid ginbuna among C. auratus and its genetic origin remain to be further elucidated.…”

“…Therefore, a variety of the triploid ginbuna that had generated by original hybridization event(s) in the past might have been widespread throughout Japan, although the possibility cannot be excluded that the same clonal lines found in different locations were caused by artificial transplantation. Nevertheless, there is a possibility that new lineages of the triploid ginbuna continue to be created considering the fact that the male tetraploid ginbuna exists, as we previously described the production of the artificial triploid ginbuna (Murakami and Fujitani, 1997).…”

“…The tetraploid ginbuna with haplotype 3 has probably resulted from genome duplication of the undefined ancestral diploid fish (an ancestor of the goldfish?) as judged from the characteristic numbers of hybridization signals of Cal3nDr repetitive and 5S rDNA-related repetitive sequences previously described (Murakami and Fujitani, 1997;.…”

“…Appropriate nuclear DNA markers are required to achieve this search. A candidate would be the Cal3nDr sequences, which were previously described (Murakami and Fujitani, 1997), as tandemly repeated DNA sequences specific to the polyploid ginbuna genomes. We developed a PCR technique enabling the detection of these sequences.…”

Population Genetic Structure of Carassius auratus (Pisces: Cypriniformes) in South Korea Inferred from AFLP Markers: Discordance with Mitochondrial Genetic Structure

“…Carassius fish species still remain controversial in their species status owing to extreme morphological variation, hybridization with related species (Hanfling et al, 2005;Tóth et al, 2005), and complicated ploidy level (Murakami and Fujitani, 1997). There had been well-established agreement on Carassius fish in South Korea until quite recently, as Yang (1985) has investigated genetic and morphological characteristics in South Korean populations, concluding that Korean population of Carassius was composed of diploid and triploid individuals of C. auratus langsdorfi.…”