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A Novel Allotriploid Hybrid Derived From Female Goldfish × Male Bleeker’s Yellow Tail

Authors :
Jing Wang
Weiguo He
Wen Wang
Ziye Luo
Linmei Han
Caixia Xiang
Mingli Chai
Tangluo Li
Jihong Li
Kaikun Luo
Rurong Zhao
Shaojun Liu
Source :
Frontiers in Genetics, Vol 13 (2022)
Publication Year :
2022
Publisher :
Frontiers Media S.A., 2022.

Abstract

Hybridization is a traditional and effective strategy to alter the genotypes and phenotypes of the offspring, and distant hybridization is a useful strategy to generate polyploids in fish. In this study, goldfish (Carassius auratus, GF, 2n = 100) and Bleeker’s yellow tail (Xenocypris davidi Bleeker, YT, 2n = 48), which belong to different subfamilies, were crossed with each other. The cross of female GF × male YT successfully obtained hybrid offspring (GFYT hybrids), while the cross of female YT × male GF was lethal, and all the fertilized eggs stopped developing before the neurula stage of embryogenesis. All GFYT hybrids possessed 124 chromosomes (3n = 124) with two sets from GF and one set from YT. The measurable and countable traits of GFYT hybrids were identified, and the genetic characteristics of 5S rDNA between GFYT hybrids and their parents were also revealed. There were, respectively, four and three different 5S rDNA types in GF (assigned as GF-Ⅰ∼Ⅳ) and YT (assigned as YT-Ⅰ∼Ⅲ), and GFYT hybrids specifically inherited YT-Ⅰ and YT-Ⅱ 5S rDNA types from YT and GF-Ⅲ and GF-Ⅳ from GF. In addition, there were only testis-like and fat-like gonads been found in GFYT hybrids. Interestingly, there were pyknotic and heteromorphous chromatin and invaginated cell membrane observed in the spermatids of testis-like gonads, but no mature sperm were found. Furthermore, TUNEL assays indicated that, compared with control, apparent apoptotic signals, which were mainly distributed around spermatid regions, were detected in the testis-like gonads, and the expression of apoptosis pathway-related genes including p53, bcl-2, bax, and caspase9 was significantly upregulated. Moreover, the expression of meiosis-related genes including spo11, dmc1, and rad51 showed an abnormally high expression, but mns1 and meig1, two key genes involved in the maturation of spermatid, were extremely downregulated. In brief, this is the first report of allotriploid via distant hybridization between GF and YT that possessing different chromosome numbers in vertebrates. The obtainment of GFYT hybrids not only harbors potential benefits and application in aquaculture but also further extends the understanding of the influence of hybridization and polyploidization on the genomic constitution of the hybrid offspring. Furthermore, they can be used as a model to test the origin and consequences of polyploidization and served as a proper resource to study the underlying mechanisms of spermatogenesis dysfunctions.

Details

Language :
English
ISSN :
16648021
Volume :
13
Database :
Directory of Open Access Journals
Journal :
Frontiers in Genetics
Publication Type :
Academic Journal
Accession number :
edsdoj.6f075a73d05c4704960c99c673923068
Document Type :
article
Full Text :
https://doi.org/10.3389/fgene.2022.880591