Genomic incompatibilities in the diploid and tetraploid offspring of the goldfish x common carp cross
Genomic incompatibilities in the diploid and tetraploid offspring of the goldfish x common carp cross
复制标题
金鱼与鲤鱼杂交的二倍体和四倍体后代的基因组不相容性
DOI：
10.1073/pnas.1512955113
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发表时间：
2016-02-02
影响因子：
11.1
通讯作者：
Zhang, Ya-Ping
中科院分区：
文献类型：
--
作者：
Liu, Shaojun;Luo, Jing;Zhang, Ya-Ping
多倍体在动物中比在植物中罕见得多，但不知道为什么。在脊椎动物中结合两个基因组的结果仍然是不可预测的，特别是因为多倍化很少显示出积极的影响，更经常导致致命的后果，因为可行的配子在减数分裂过程中无法形成。幸运的是，金鱼（母本）×鲤鱼（父本）杂交后代已成功繁殖到第22代，这种杂交谱系允许对杂交和四倍化的基因组学进行研究。这些杂种的前两代是二倍体，随后的几代是四倍体。四代及其祖先的肝转录组显示嵌合基因（> 9%）和正向基因突变。从基因组DNA和cDNA中随机选择的18个基因的表征证实了嵌合体。一些嵌合和差异表达的基因与2nF中的诱变、修复和癌症相关途径有关（1）。同源亲本基因之间的错误DNA切除可能导致高比例的嵌合基因，或者甚至更多潜在的机制可能导致这种现象。同时，二倍体后代表现出偏父表达，而四倍体表现出偏母表达。这些发现表明，快速和不稳定的变化主要是有害的转录组水平，虽然一些后代仍然生存的基因组异常。此外，基因组休克的合成效应可能导致2nF（2）杂种后代的生存力大大降低。金鱼×鲤鱼杂交组合是揭示杂交脊椎动物基因组间相互作用及其生育力的理想系统。
Polyploidy is much rarer in animals than in plants but it is not known why. The outcome of combining two genomes in vertebrates remains unpredictable, especially because polyploidization seldom shows positive effects and more often results in lethal consequences because viable gametes fail to form during meiosis. Fortunately, the goldfish (maternal) x common carp (paternal) hybrids have reproduced successfully up to generation 22, and this hybrid lineage permits an investigation into the genomics of hybridization and tetraploidization. The first two generations of these hybrids are diploids, and subsequent generations are tetraploids. Liver transcriptomes from four generations and their progenitors reveal chimeric genes (> 9%) and mutations of orthologous genes. Characterizations of 18 randomly chosen genes from genomic DNA and cDNA confirm the chimera. Some of the chimeric and differentially expressed genes relate to mutagenesis, repair, and cancer-related pathways in 2nF(1). Erroneous DNA excision between homologous parental genes may drive the high percentage of chimeric genes, or even more potential mechanisms may result in this phenomenon. Meanwhile, diploid offspring show paternal-biased expression, yet tetraploids show maternal-biased expression. These discoveries reveal that fast and unstable changes are mainly deleterious at the level of transcriptomes although some offspring still survive their genomic abnormalities. In addition, the synthetic effect of genome shock might have resulted in greatly reduced viability of 2nF(2) hybrid offspring. The goldfish x common carp hybrids constitute an ideal system for unveiling the consequences of intergenomic interactions in hybrid vertebrate genomes and their fertility.