异育银鲫“中科3号”是中国科学院水生生物研究所桂建芳研究员等在鉴定出可区分银鲫不同克隆系的分子标记，证实银鲫同时存在单性雌核生殖和有性生殖双重生殖方式的基础上，利用银鲫双重生殖方式，从D系银鲫（♀）与A系银鲫（♂）交配所产后代中筛选出少数优良个体，再经雌核生殖增殖扩群，经多代生长对比养殖试验评价培育出来的水产新品种。
最近，该实验室研究人员进一步对异育银鲫“中科3号”的遗传特征进行了染色体计数、Cot-1 DNA荧光显带核型、微卫星DNA标记、AFLP标记、转铁蛋白等位基因序列以及线粒体DNA全序列等比较分析。研究结果表明，异育银鲫“中科3号”的核基因组与A系银鲫的核基因组相同，而线粒体DNA全序列与D系银鲫的线粒体DNA相同。由此揭示异育银鲫“中科3号”是一个新的核质杂种克隆，其形成的机制是A系银鲫的精子在D系银鲫的卵质中经雄核发育产生。人工繁育实验及其连续七代的微卫星DNA和AFLP标记分析表明，异育银鲫“中科3号”仍然保留了单性雌核生殖的能力，产生遗传性状与其克隆繁殖用的核质杂种母本完全一致的后代，遗传性状稳定。这一新的发现对开拓银鲫的遗传育种途径具有重要意义，因为由此产生的核质杂种克隆避免了在人工诱导雄核发育和核移植中使用的辐射和物理休克所造成的遗传和发育损伤；其次，这一发现还有助于了解单性脊椎动物克隆多样性产生的原因，对研究其它单性动物的进化遗传学和生态学也有重要意义。
该研究得到国家大宗淡水鱼类产业技术体系和国家基础研究973计划等项目的资助，主要由王忠卫副研究员等完成，通讯作者为桂建芳研究员，相关论文已于近日以Research article在线发表在《BMC研究笔记》（BMC Research Notes） 。（生物谷Bioon.com）
生物谷推荐原文出处：
BMC Research Notes 2011, 4:82
A novel nucleo-cytoplasmic hybrid clone formed via androgenesis in polyploid gibel carp
Zhong-Wei Wang , Hua-Ping Zhu , Da Wang , Fang-Fang Jiang , Wei Guo , Li Zhou and Jian-Fang Gui
Background
Unisexual vertebrates have been demonstrated to reproduce by gynogenesis, hybridogenesis, parthenogenesis, or kleptogenesis, however, it is uncertain how the reproduction mode contributes to the clonal diversity. Recently, polyploid gibel carp has been revealed to possess coexisting dual modes of unisexual gynogenesis and sexual reproduction and to have numerous various clones. Using sexual reproduction mating between clone D female and clone A male and subsequent 7 generation multiplying of unisexual gynogenesis, we have created a novel clone strain with more than several hundred millions of individuals. Here, we attempt to identify genetic background of the novel clone and to explore the significant implication for clonal diversity contribution.
Methods
Several nuclear genome markers and one cytoplasmic marker, the mitochondrial genome sequence, were used to identify the genetic organization of the randomly sampled individuals from different generations of the novel clone.
Results
Chromosome number, Cot-1 repetitive DNA banded karyotype, microsatellite patterns, AFLP profiles and transferrin alleles uniformly indicated that nuclear genome of the novel clone is identical to that of clone A, and significantly different from that of clone D. However, the cytoplasmic marker, its complete mtDNA genome sequence, is same to that of clone D, and different from that of clone A.
Conclusions
The present data indicate that the novel clone is a nucleo-cytoplasmic hybrid between the known clones A and D, because it originates from the offspring of gonochoristic sexual reproduction mating between clone D female and clone A male, and contains an entire nuclear genome from the paternal clone A and a mtDNA genome (cytoplasm) from the maternal clone D. It is suggested to arise via androgenesis by a mechanism of ploidy doubling of clone A sperm in clone D ooplasm through inhibiting the first mitotic division. Significantly, the selected nucleo-cytoplasmic hybrid female still maintains its gynogenetic ability. Based on the present and previous findings, we discuss the association of rapid genetic changes and high genetic diversity with various ploidy levels and multiple reproduction modes in several unisexual and sexual complexes of vertebrates and even other invertebrates.
