A Novel Allotriploid Hybrid Derived From Female Goldfish × Male Bleeker's Yellow Tail.
A Novel Allotriploid Hybrid Derived From Female Goldfish × Male Bleeker's Yellow Tail.
复制标题
一种由雌性金鱼和雄性布利克黄尾鱼衍生的新型异源三倍体杂交体
DOI：
10.3389/fgene.2022.880591
复制
发表时间：
2022
影响因子：
3.7
通讯作者：
中科院分区：
文献类型：
--
作者：
杂交是改变后代基因型和表型的传统且有效的策略，而远缘杂交是在鱼类中产生多倍体的有用策略。在本研究中，将属于不同亚科的金鱼（Carassius auratus，GF，2n = 100）和布利克黄尾鱼（Xenocypris davidi Bleeker，YT，2n = 48）相互杂交。雌性GF×雄性YT杂交成功获得杂种后代（GFYT杂种），而雌性YT×雄性GF杂交是致死的，所有受精卵在胚胎发生神经胚阶段之前停止发育。所有 GFYT 杂交体均拥有 124 条染色体 (3n = 124)，其中两组来自 GF，一组来自 YT。鉴定了GFYT杂种的可测性和可数性状，揭示了GFYT杂种与其亲本的5S rDNA遗传特征。 GF（记为GF-Ⅰ～Ⅳ）和YT（记为YT-Ⅰ～Ⅲ）分别存在4种和3种不同的5S rDNA类型，并且GFYT杂种特异地遗传了YT的YT-Ⅰ和YT-Ⅱ 5S rDNA类型以及GF-Ⅲ和GF-IV的5S rDNA类型。此外，在GFYT杂种中只发现了类睾丸和类脂肪的性腺。有趣的是，在类睾丸性腺的精子细胞中观察到固缩、异形染色质和内陷的细胞膜，但没有发现成熟的精子。此外，TUNEL检测表明，与对照相比，在类睾丸性腺中检测到明显的凋亡信号，主要分布在精子细胞区域周围，并且p53、bcl-2、bax和caspase9等凋亡途径相关基因的表达显着上调。此外，包括spo11、dmc1和rad51在内的减数分裂相关基因的表达呈现异常高表达，但参与精子成熟的两个关键基因mns1和meig1却极度下调。简而言之，这是脊椎动物中首次报道具有不同染色体数目的GF和YT通过远距离杂交获得异源三倍体。 GFYT杂种的获得不仅在水产养殖中具有潜在的效益和应用，而且进一步扩展了对杂交和多倍体化对杂种后代基因组构成影响的理解。此外，它们可以用作测试多倍体化的起源和后果的模型，并作为研究精子发生功能障碍的潜在机制的适当资源。
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.