Stable Genome Incorporation of Sperm-derived DNA Fragments in Gynogenetic Clone of Gibel Carp
Stable Genome Incorporation of Sperm-derived DNA Fragments in Gynogenetic Clone of Gibel Carp
复制标题
银鲫雌核发育克隆中精子来源 DNA 片段的稳定基因组整合
DOI：
10.1007/s10126-019-09930-w
复制
发表时间：
2020-01-04
影响因子：
3
通讯作者：
Gui, Jian-Fang
中科院分区：
文献类型：
--
作者：
Chen, Fan;Li, Xi-Yin;Gui, Jian-Fang
单性动物如何消除有害突变以避免死胡同是进化遗传学中最有趣的谜题之一。在雌核发育动物中已经观察到来自外源精子的微染色体的整合，但对它们的详细过程和遗传命运知之甚少。在这里，我们显示了一个稳定的基因组掺入的情况下，在人工克隆F的雌核发育异育银鲫（Carassius gibelio）。通过读段深度依赖比较策略筛选出12个外源DNA片段，经SCAR标记检测证实为F克隆和团头鲂父本的特异性片段。在雌核发育早期的某些样品中未检测到这些精子DNA片段，但经过13代的人工雌核发育选择，在所有被检个体中均发现了这些片段，这意味着它们可能已稳定地整合到克隆F的基因组中。染色体定位和序列分析表明，最大的片段CgA22_34来源于团头鲂non-LTR反转录转座子，并持久地整合到银鲫克隆F的三条同源染色体中的一条上。本研究结果表明，异育银鲫精子DNA片段的整合可以增加异育银鲫的遗传多样性，为异育银鲫的遗传育种带来新的性状。在此过程中，转座因子（transposable elements，TE）在基因组结构的形成中起着重要的作用。同时，掺入的DNA片段能够被用作遗传标记，在异育银鲫的水产养殖实践中进行选择性育种计划。
How unisexual animals eliminate deleterious mutations to avoid dead ends is one of the most interesting puzzles in evolutionary genetics. Incorporation of microchromosomes derived from exogenous sperm had been observed in gynogenetic animals, but little is known about their detailed process and hereditary fate. Here, we show a stable genome incorporation case in an artificial clone F of gynogenetic gibel carp (Carassius gibelio). A total of 12 exogenous DNA fragments were screened through a read depth-dependent comparison strategy and confirmed to be specific to the clone F and the paternal blunt snout bream (Megalobrama amblycephalaYin) by SCAR (sequence characterized amplified regions) marker detection. Moreover, these sperm-derived DNA fragments were not detected in some samples in early gynogenetic generations, but they were found to exist in all examined individuals through artificial gynogenetic selections of 13 generations, implying that they might have stably incorporated into the genome of clone F. Furthermore, chromosome localization and sequence characterization indicate that the largest fragmentCgA22_34 is derived from blunt snout bream non-LTR retrotransposon and durably incorporated into only one of three homologous chromosomes of gibel carp clone F. Our results suggest that the incorporated sperm-derived DNA fragments by allogynogenesis should increase genetic diversity and introduce new traits into unisexual animals which will benefit genetic breeding of gibel carp. During the process, transposable elements (TEs) may play significant roles in shaping the genome structures. Simultaneously, the incorporated DNA fragments are able to be used as genetic markers to perform selective breeding programs in aquaculture practices of gibel carp.