Qin QinBo, Wang Juan, Wang YuDe, Liu Yun, Liu ShaoJun
Key Laboratory of Protein Chemistry and Developmental Biology of the State Education Ministry of China, College of Life Sciences, Hunan Normal University, Changsha, 410018, People's Republic of China.
BMC Genet. 2015 Mar 13;16:26. doi: 10.1186/s12863-015-0186-z.
The offspring with 100 chromosomes (abbreviated as GRCC) have been obtained in the first generation of Carassius auratus red var. (abbreviated as RCC, 2n = 100) (♀) × Megalobrama amblycephala (abbreviated as BSB, 2n = 48) (♂), in which the females and unexpected males both are found. Chromosomal and karyotypic analysis has been reported in GRCC which gynogenesis origin has been suggested, but lack genetic evidence.
Fluorescence in situ hybridization with species-specific centromere probes directly proves that GRCC possess two sets of RCC-derived chromosomes. Sequence analysis of the coding region (5S) and adjacent nontranscribed spacer (abbreviated as NTS) reveals that three types of 5S rDNA class (class I; class II and class III) in GRCC are completely inherited from their female parent (RCC), and show obvious base variations and insertions-deletions. Fluorescence in situ hybridization with the entire 5S rDNA probe reveals obvious chromosomal loci (class I and class II) variation in GRCC.
This paper provides directly genetic evidence that GRCC is gynogenesis origin. In addition, our result is also reveals that distant hybridization inducing gynogenesis can lead to sequence and partial chromosomal loci of 5S rDNA gene obvious variation.
在红鲫（简称RCC，2n = 100）♀×团头鲂（简称BSB，2n = 48）♂的第一代中获得了具有100条染色体的后代（简称GRCC），其中发现了雌性和意外出现的雄性。已报道了GRCC的染色体和核型分析，推测其起源为雌核发育，但缺乏遗传证据。
用物种特异性着丝粒探针进行荧光原位杂交直接证明GRCC拥有两组源自红鲫的染色体。对编码区（5S）和相邻非转录间隔区（简称NTS）的序列分析表明，GRCC中的三种类型的5S rDNA类（I类；II类和III类）完全从其母本（RCC）遗传而来，并表现出明显的碱基变异和插入缺失。用整个5S rDNA探针进行荧光原位杂交揭示了GRCC中明显的染色体位点（I类和II类）变异。
本文提供了直接的遗传证据，证明GRCC起源于雌核发育。此外，我们的结果还表明，远缘杂交诱导雌核发育可导致5S rDNA基因的序列和部分染色体位点发生明显变异。
