The Sterility of Allotriploid Fish and Fertility of Female Autotriploid Fish

Abstract

Based on the formation of an autotetraploid fish line (4nAUT, 4n = 200; F 2 –F 11 ) derived from the distant hybridization of female Carassius auratus red var. (RCC, 2n = 100) × male Megalobrama amblycephala (BSB, 2n = 48), we produced autotriploid hybrids (3nAUT) by crossing females of RCC with males of 4nAUT and allotriploid hybrids (3nALT) by crossing females of Cyprinus carpio (CC, 2n = 100) with males of 4nAUT. The aim of this study was to comparatively investigate the reproductive characteristics of 3nALT and 3nAUT. We investigated morphological traits, chromosomal numbers, DNA content and gonadal development in 3nAUT and 3nALT. The results indicated both 3nAUT and 3nALT possessed 150 chromosomes and were triploid hybrids. The females and males of 3nALT and males of 3nAUT had abnormal gonadal development and could not generate mature eggs or sperm, but the females of 3nAUT had normal gonadal development and generated mature eggs at 2 years old. The females of 3nAUT generated different sizes of eggs, which fertilized with haploid sperm from RCC and formed viable diploid, triploid, and tetraploid offspring. The formation of these two kinds of triploid hybrids provides an ideal model for studying the reproductive traits of triploid hybrids, which is of great value in animal genetics and reproductive biology.

The establishment of the fertile fish lineages derived from distant hybridization by overcoming the reproductive barriers

“…For example, the triploid fish has been produced by the hybridization of the white crucian carp (C. cuvieri, 2n = 100, ♀) and the allotetraploid hybrids (4n = 200, ♂) (Liu et al 2001, Guo et al 2006. Additionally, autotriploid fish has been produced by the crossing of red crucian carp (2n = 100, ♀) and autotetraploid hybrids (4n = 200, ♂), and allotriploid hybrids has been produced by the hybridization of common carp (2n = 100, ♀) and autotetraploid hybrids (4n = 200, ♂) (Hu et al 2019).…”

Formation of autotriploid Carassius auratus and its fertility-related genes analysis

“…Xiao et al [ 25 ] reported that triploid Carassius auratus in Dongting water system produces normal gametes. Hu et al [ 26 ] reported that female autotriploid hybrids (3nAUT) generated by crossing females of Carassius auratus red var. with males of autotetraploid fish produced mature eggs.…”

Sox Gene Family Revealed Genetic Variations in Autotetraploid Carassius auratus

“…In previous studies, we artificially obtained fertile allotetraploids (4nRB, 4n = 148, F 1 ) from the distant hybridization of 2nRCC (♀) × BSB (♂) ( Liu et al, 2007 ). The fertile 4nRCC (4n = 200) was obtained through the fertilization of diploid sperm and eggs caused by the abnormal chromosome behavior during meiosis of 4nRB, and the 4nRCC lineage (F 2 –F 14 ) was established through continuous self-crossing ( Qin et al, 2014 ; Hu et al, 2019 ). The newly synthesized 4nRCC possessed four sets of chromosomes from 2nRCC and produced diploid gametes, and there were obvious phenotypic differences between 2nRCC and 4nRCC ( Qin et al, 2014 ; Qin Q. et al, 2018 ; Qin Q.…”