Nucleolar Dominance in a Tetraploidy Hybrid Lineage Derived From Carassius auratus red var. () × Megalobrama amblycephala ().

Liu Cao,Xu Huang,Kaikun Luo,Jin Wen,Qiong Xiao,Yangyang Huo,Hongting Yin,Qiwen Liu,Min Tao,Shaojun Liu,Qinbo Qin,Chun Zhang

doi:10.3389/fgene.2018.00386

Abstract

Nucleolar dominance is related to the expression of 45S rRNA genes inherited from one progenitor due to the silencing of the other progenitor’s rRNA genes. To investigate nucleolar dominance associated with tetraploidization, we analyzed the changes regarding the genetic traits and expression of 45S rRNA genes in tetraploidy hybrid lineage including F1 allotetraploids (4n = 148) and F2 autotetraploids (4n = 200) derived from the distant hybridization of Carassius auratus red var. (2n = 100) () ×Megalobrama amblycephala (2n = 48) (). Results showed that nucleolar dominance from the females was established in F1 hybrids and it was inherited in F2 hybrids, suggesting that tetraploidization can lead to rapid establishment of nucleolar dominance in the hybrid origin’s tetraploid lineage. These results extend the knowledge of nucleolar dominance in polyploidy hybrid animals, which are of significance for the evolution of hybrids in vertebrates.

Highlights

Polyploidy species have played a major role in the evolution and the adaptation of eukaryotes in both animals (Muller, 1925; Peer et al, 2009) and plants (Levy and Feldman, 2002; Soltis et al, 2009; Jiao et al, 2011)
The results showed that nucleolar dominance from the females was established in F1 hybrids and it was inherited in F2 hybrids, suggesting that tetraploidization can lead to rapid establishment of nucleolar dominance in the hybrid origin’s tetraploid lineage
These results extend the knowledge of nucleolar dominance in polyploidy hybrid animals, which are of significance for the evolution of hybrids in vertebrates

Summary

Introduction

Polyploidy species have played a major role in the evolution and the adaptation of eukaryotes in both animals (Muller, 1925; Peer et al, 2009) and plants (Levy and Feldman, 2002; Soltis et al, 2009; Jiao et al, 2011). Hybridization is one of the primary mechanisms for the origin of species leading to the formation of polyploids (Otto and Whitton, 2000; Liu, 2010). It is assumed that these genomic changes facilitate the establishment and success of the newly formed polyploids (Song et al, 1995; Ozkan et al, 2001; Kashkush et al, 2002; Raskina et al, 2002). Fertile allotetraploids (abbreviated as F1) (AABB, 4n = 148) were successfully obtained in the first generation derived from the distant hybridization of Carassius auratus red var. Fertile autotetraploids (abbreviated as F2) (AAAA, 4n = 200) were obtained in the second generation through crossing autodiploid sperm and autodiploid ova produced by abnormal chromosome behavior during meiosis of F1 hybrids (Qin et al, 2014). In contrast with the F1 hybrids, the F2 hybrids have increasing the fertility and reach sexual maturity at 1 year old

Methods

Results

Conclusion