红鲫属鲤亚科，其染色体数目为2n=100；团头鲂属于鲌亚科，其染色体数目为2n=48。在红鲫（♀）×；团头鲂（♂）的远缘杂交F₁代中获得了异源三倍体鲫鲂和异源四倍体鲫鲂。本研究对异源三倍体鲫鲂进行了染色体核型分析、染色体FISH杂交检测和性腺结构观察，结果表明：1）异源三倍体鲫鲂的染色体数目为3n=124，染色体核型公式为31m+45sm+26st+22t，染色体组由2套红鲫染色体和1套团头鲂染色体组成；2）利用红鲫特有重复序列为探针进行FISH杂交，红鲫的100条染色体均被标记上荧光信号，而团头鲂的染色体均未标记上荧光信号，异源三倍体鲫鲂中有100条染色体被标记上荧光信号，说明异源三倍体鲫鲂含有2套红鲫来源的染色体组；3）异源三倍体鲫鲂的性腺发育异常，其卵巢型和精巢型性腺发育呈现出退化的特征。研究还讨论了异源三倍体鲫鲂的形成机制。实验结果为鱼类远缘杂交和多倍体鱼研究提供了实验数据，在鱼类遗传育种方面具有重要意义。

Red crucian carp(abbreviated as RCC)with 100 chromosomes belonged to the Cyprininae subfamily,and the blunt snout bream(Megalobrama amblycephala)(abbreviated as BSB)with 48 chromosomes belonged to the Cultrinae subfamily.In the first generation of RCC(♀)×BSB(♂),we obtained triploid hybrids(abbreviated as 3nRB)and tetraploid hybrids(abbreviated as 4nRB).In this study,we made the analysis of karyotype of the chromosomes,FISH of the chromosomes and the gonadal development in 3nRB.The results are as follows:(1)3nRB hybrids had 124 chromosomes with a karyotype of 31m+45sm+26st+22t,which possessed two sets of RCC-derived chromosomes,and one set of BSB-derived chromosomes.(2)The species-specific repetitive sequences probe hybridized to 100 chromosomes in RCC but none in BSB.In 3nRB,the probe hybridized to 100 chromosomes,suggesting that they possessed two sets of RCC-derived chromosomes.(3)The gonad of 3nRB displayed developmental anomaly,which was considered as a retrogression trait.This paper discussed the formation mechanism of 3nRB,and provided experimental data for study of distant hybridization and polyploidy in fish,which is of importance in genetic breeding.

国家自然科学基金青年项目（31201987）；教育部博士点基金（20124306120006）；湖南省教育厅青年项目（12B084）；湖南省自然科学基金青年人才联合培养基金（14JJ6008）；国家自然科学基金重大国际合作项目（31210103918）；国家自然科学基金重大研究计划培育项目（91331105）；国家自然科学基金重点项目（30930071）；“九七三”前期项目（2012CB722305）；高等学校博士学科点专项科研基金（20114306130001）；湖南省生物发育工程及新产品研发协同创新中心（20134486）