捞刀河浏阳段河蚬的遗传多样性及生殖特征研究

GENETIC DIVERSITY AND REPRODUCTIVE CHARACTERISTICS OF CORBICULA FLUMINEA FROM THE LAODAO RIVER IN LIUYANG CITY

  • 摘要: 研究以线粒体细胞色素氧化酶Ⅰ(COⅠ) 部分序列(614 bp)为分子标记, 对捞刀河浏阳段河蚬Corbicula fluminea (n=40)的种群遗传多样性进行评价, 并分别从性腺组织学和精子形态学两方面分析其生殖特征, 以期丰富河蚬的繁殖生物学信息, 为开展其人工繁殖及资源保护提供参考。结果显示, 40条河蚬COⅠ基因序列共检出4种单倍型, 17个变异位点, 平均单倍型多样性、平均核苷酸多样性和平均核苷酸差异数分别为 0.664±0.042、0.014±0.006和8.595。捞刀河浏阳段河蚬存在雌雄同体和雌雄异体2种性别系统, 雌雄同体、雄性和雌性的性比约为6﹕3﹕1。雌雄同体个体生殖滤泡存在滤泡混合型和滤泡并存型2种类型。23个雌雄同体和8个雄性个体的精子均为双鞭毛。结果表明, 捞刀河浏阳段河蚬种群的遗传多样性相对较低, 生殖方式多样且以雄核生殖为主。

     

    Abstract: This study attempted to theoretically support and comprehensively perceive genetic diversity and reproduction of Corbicula fluminea from the Laodao River in Liuyang city was investigated. Partial sequences of the cytochrome oxidase c subunit 1 (COⅠ) of mitochondrial genes were utilized to evaluate the genetic diversity, and reproductive characteristics were observed by gonadal histology and sperm morphology using light microscopy. Among examined 40 individuals, only 4 haplotypes and 17 variable sites were detected in the partial sequences of the COⅠ, with an average haplotype diversity, nucleotide diversity, and number of variable sites equal to 0.664±0.042, 0.014±0.006, and 8.595, respectively. Hermaphrodite was a predominant reproduction in the population studied, and the hybrid hermaphrodite-sex ratio was 6﹕3﹕1. Furthermore, there were two types of reproductive follicles in hermaphroditic individuals, including sperm and egg cells in the same and in different follicular cells. The observation of sperm morphology revealed that biflagellate spermatozoa were discovered in both hermaphrodite (n=23) and male (n=8) cases. The results also showed that Corbicula fluminea samples from the Laodao River of Liuyang city contained a relatively low genetic diversity, but with multiple reproduction modes, and the predominant mode was androgenesis. This study attempted to present significant biological reproduction information required for Corbicula fluminea protection in China.

     

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