Rapid Genomic and Genetic Changes in the First Generation of Autotetraploid Lineages Derived from Distant Hybridization of Carassius auratus Red Var. (♀) × Megalobrama amblycephala (♂)
Autopolyploids are traditionally used to demonstrate multivalent pairing and unstable inheritance. However, the autotetraploid fish (4nRR) (RRRR, 4n = 200) derived from the distant hybridization of Carassius auratus red var. (RCC) (RR, 2n = 100) (♀) × Megalobrama amblycephala (BSB) (BB, 2n = 48) (♂) exhibits chromosome number (or ploidy) stability over consecutive generations (F1–F10). Comparative analysis based on somatic and gametic chromosomal loci [centromeric, 5S rDNA, and Ag-NORs (silver-stained nucleolar organizer regions)] revealed that a substantial loss of chromosomal loci during genome doubling increases the divergence between homologous chromosomes and that diploid-like chromosome pairing was restored during meiosis in the first generation of 4nRR lineages. In addition, a comparative analysis of genomes and transcriptomes from 4nRR (F1) and its diploid progenitor (RCC) exhibited significant genomic structure and gene expression changes. From these data, we suggest that genomes and genes diverge and that expression patterns change in the first generations following autotetraploidization, which are processes that might contribute to the stable inheritance and successful establishment of autotetraploid lineages.
KeywordsAutotetraploid lineages Chromosomal locus Genome Transcriptome Meiosis
This study is conceived and designed by S.J.L. and Q.B.Q; Q.B.Q. contributed experimental work, most statistical analyses and the manuscript writing; L.C., Y.D.W., and L.R. contributed primers design and bioinformatics analyses; Q.W.L., Y.W.Z., C.Q.W., H.Q., and C.Z. contributed experimental materials and data collect. All authors read and approve the final manuscript.
This research was financially supported by grants from the Natural Science Foundation of Hunan Province for Distinguished Young Scholars (Grant Nos. 2017JJ1022), the Key Research and Development Program of Hunan Province (Grant Nos. 2018NK2072), the National Natural Science Foundation of China (Grant Nos. 31430088 and 31210103918), the Major Program of the Educational Commission of Hunan Province (Grant No. 17A133), the State Key Laboratory of Developmental Biology of Freshwater Fish, the Cooperative Innovation Center of Engineering and New Products for Developmental Biology of Hunan Province (20134486), the Earmarked Fund for China Agriculture Research System (CARS-45) and the Construction Project of Key Disciplines of Hunan Province and China.
Compliance with Ethical Standards
All the fish were cultured in ponds at the Protection Station of Polyploid Fish, Hunan Normal University, and fed with artificial feed. Fish treatments were performed according to the Care and Use of Agricultural Animals in Agricultural Research and Teaching, approved by the Science and Technology Bureau of China. Approval from the Department of Wildlife Administration was not required for the experiments conducted in this study. Fish were deeply anesthetized with 100 mg/L MS-222 (Sigma-Aldrich) before dissection.
The authors declare that they have no competing interests.
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