Artificial whole genome duplication in paleopolyploid sturgeons yields highest documented chromosome number in vertebrates

Abstract

Critically endangered sturgeons, having undergone three whole genome duplication events, represent an exceptional example of ploidy plasticity in vertebrates. Three extant ploidy groups, combined with autopolyploidization, interspecific hybridization and the fertility of hybrids are important issues in sturgeon conservation and aquaculture. Here we demonstrate that the sturgeon genome can undergo numerous alterations of ploidy without severe physiological consequences, producing progeny with a range of ploidy levels and extremely high chromosome numbers. Artificial suppression of the first mitotic division alone, or in combination with suppression of the second meiotic division of functionally tetraploid zygotes (4n, C-value = 4.15) of Siberian sturgeon Acipenser baerii and Russian sturgeon A. gueldenstaedtii resulted in progeny of various ploidy levels—diploid/hexaploid (2n/6n) mosaics, hexaploid, octoploid juveniles (8n), and dodecaploid (12n) larvae. Counts between 477 to 520 chromosomes in octoploid juveniles of both sturgeons confirmed the modal chromosome numbers of parental species had been doubled. This exceeds the highest previously documented chromosome count among vertebrates 2n ~ 446 in the cyprinid fish Ptychobarbus dipogon.

Effects of Hydrostatic Pressure Treatment of Newly Fertilized Eggs on the Ploidy Level and Karyotype of Pikeperch Sander lucioperca (Linnaeus, 1758)

“…According to that study, a possible explanation for the mosaicism is that the second polar body is retained but does not fuse with the sperm, resulting in binuclear cells. Polyploid-diploid mosaic individuals were also reported by Smith and Lemoine (1979) [27] in the case of larvae (fry) hatched from colchicine-treated brook trout eggs and in sturgeon fishes treated by heat shock [28]. Allen and Stanley (1979) [29] found triploid-diploid mosaic individuals among the larvae of Atlantic salmon, when fertilized eggs were treated with cytochalasin B.…”

Transcriptome and Proteome Analyses Reveal Stage-Specific DNA Damage Response in Embryos of Endangered Sturgeon

“…They represent an attractive model for studying DDR owing to their multiple rounds of lineage-speci c whole-genome duplication [13]. Furthermore, sturgeons have extraordinary genomic plasticity, as demonstrated through intraspeci c hybridization of individuals with different chromosome numbers [14], events of spontaneous polyploidization [15,16], and arti cial ploidy manipulation that yields the highest documented chromosome number in vertebrates [17].…”

Transcriptome and Proteome Analyses Reveal Stage-Specific DNA Damage Response in Embryos of Sturgeon (Acipenser ruthenus)

“…They represent an attractive model for studying DDR owing to their multiple rounds of lineage-specific whole-genome duplication [ 13 ]. Furthermore, sturgeons have extraordinary genomic plasticity, as demonstrated through intraspecific hybridization of individuals with different chromosome numbers [ 14 ], events of spontaneous polyploidization [ 15 , 16 ], and artificial ploidy manipulation that yields the highest documented chromosome number in vertebrates [ 17 ]. According to the authors of [ 18 ], genome size is linearly related to the number of DNA repair genes and proteins.…”