title: Tempo and mode of recurrent polyploidization in the Carassius auratus species complex (Cypriniformes, Cyprinidae).
abstract: Polyploidization is an evolutionarily rare but important mechanism in both plants and animals because it increases genetic diversity. Goldfish of the Carassius auratus species complex can be tetraploids, hexaploids and octaploids. Polyploidization events have occurred repeatedly in goldfish, yet the extent of this phenomenon and its phyletic history are poorly understood. We explore the origin, tempo and frequency of polyploidization in Chinese and Japanese goldfish using both mitochondrial (mtDNA) and nuclear DNA sequences from up to 1202 individuals including the outgroup taxon, Cyprinus carpio. Analyses of de novo nuclear gene data resolve two clusters of alleles and the pattern supports the prior hypothesis of an ancient allotetraploidization for Carassius. Alleles shared by tetraploid and hexaploid individuals indicate recent autoploidizations within the C. auratus complex. Sympatric tetraploids and hexaploids share mtDNA haplotypes and these frequently occur independently within six well-supported lineages and sublineages on a small spatial scale. Gene flow estimates (Fst values) indicate that hexaploids differ only slightly from sympatric tetraploids, if at all. In contrast, allopatric populations of tetraploids and hexaploids differ from one another to a far greater extent. Gene flow between sampled localities appears to be limited. Coalescence-based time estimations for hexaploids reveal that the oldest lineage within any sampled locality is around one million years old, which is very young. Sympatric, recurrent autoploidization occurs in all sampled populations of the C. auratus complex. Goldfish experience polyploidization events more frequently than any other vertebrate.
authors.affiliation: Laboratory of Conservation and Utilization of Bio-resources and Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan, China.
authors.forename: J
authors.initials: J
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution and Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Laboratory of Conservation and Utilization of Bio-resources and Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan, China.
authors.forename: W
authors.initials: W
authors.lastname: Ma
authors.affiliation: Laboratory of Conservation and Utilization of Bio-resources and Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan, China.
authors.forename: X-y
authors.initials: XY
authors.lastname: Bi
authors.affiliation: 1] State Key Laboratory of Genetic Resources and Evolution and Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China [2] School of life sciences, University of Science and Technology of China, Hefei, Anhui, China.
authors.forename: S-y
authors.initials: SY
authors.lastname: Wang
authors.affiliation: Laboratory of Conservation and Utilization of Bio-resources and Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan, China.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.affiliation: Laboratory of Conservation and Utilization of Bio-resources and Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan, China.
authors.forename: Y-q
authors.initials: YQ
authors.lastname: Wang
authors.affiliation: Laboratory of Conservation and Utilization of Bio-resources and Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan, China.
authors.forename: J
authors.initials: J
authors.lastname: Chai
authors.affiliation: Laboratory of Conservation and Utilization of Bio-resources and Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan, China.
authors.forename: R
authors.initials: R
authors.lastname: Du
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution and Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.
authors.forename: S-f
authors.initials: SF
authors.lastname: Wu
authors.affiliation: Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Konstanz, Baden-Wu¨rttemberg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Meyer
authors.affiliation: Laboratory of Conservation and Utilization of Bio-resources and Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan, China.
authors.forename: R-g
authors.initials: RG
authors.lastname: Zan
authors.affiliation: Laboratory of Conservation and Utilization of Bio-resources and Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan, China.
authors.forename: H
authors.initials: H
authors.lastname: Xiao
authors.affiliation: 1] State Key Laboratory of Genetic Resources and Evolution and Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China [2] Centre for Biodiversity and Conservation Biology, Royal Ontario Museum, Toronto, ON, Canada.
authors.forename: R W
authors.initials: RW
authors.lastname: Murphy
authors.affiliation: 1] Laboratory of Conservation and Utilization of Bio-resources and Key Laboratory for Animal Genetic Diversity and Evolution of High Education in Yunnan Province, School of Life Sciences, Yunnan University, Kunming, Yunnan, China [2] State Key Laboratory of Genetic Resources and Evolution and Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.
authors.forename: Y-p
authors.initials: YP
authors.lastname: Zhang
mesh_terms: D000818:Animals; D003531:Cypriniformes / Q000235:genetics*; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D011123:Polyploidy