Genomic and transcriptomic investigations of the evolutionary transition from oviparity to viviparity
Genomic and transcriptomic investigations of the evolutionary transition from oviparity to viviparity
复制标题
从卵生到胎生进化转变的基因组和转录组研究
DOI：
10.1073/pnas.1816086116
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发表时间：
2019-02-26
影响因子：
11.1
通讯作者：
Che, Jing
中科院分区：
文献类型：
--
作者：
Gao, Wei;Sun, Yan-Bo;Che, Jing
胎生脊椎动物在其他卵生（产卵）分支中反复进化。超过三分之二的脊椎动物生殖奇偶模式的变化发生在有鳞爬行动物中，这种转变发生了98到129次。从卵生到胎生的转变需要雌性生殖道的许多生理、形态和免疫学变化，包括蛋壳减少、延迟产卵、胎盘发育以由母体向胚胎提供水和营养、增强气体交换和抑制母体对胚胎的免疫排斥。我们进行了基因组和转录组学分析的一个密切相关的卵生胎生对蜥蜴（Phrynocephalus przewalskii和Phrynocephalus vlangalii），以检查这些转换。在卵和胚胎的生殖发育过程中，两个物种的母体输卵管表达模式存在显著差异。我们发现了相应基因表达模式的变化，这些基因解释了卵生到胎生过渡的每个主要方面。此外，我们比较了四个卵生-胎生对蜥蜴在不同属（沙蜥，Erephelus，Scincella和Sphenomorphus）的转录组中的基因序列，以寻找可能的基因收敛在序列水平上。我们发现在氨基酸替换和进化速率转变方面的趋同程度都很低。这表明，大多数产生卵生-胎生转变的变化是基因表达的变化，因此偶尔从胎生逆转为卵生可能并不像以前所建议的那样难以实现。
Viviparous (live-bearing) vertebrates have evolved repeatedly within otherwise oviparous (egg-laying) clades. Over two-thirds of these changes in vertebrate reproductive parity mode happened in squamate reptiles, where the transition has happened between 98 and 129 times. The transition from oviparity to viviparity requires numerous physiological, morphological, and immunological changes to the female reproductive tract, including eggshell reduction, delayed oviposition, placental development for supply of water and nutrition to the embryo by the mother, enhanced gas exchange, and suppression of maternal immune rejection of the embryo. We performed genomic and transcriptomic analyses of a closely related oviparous-viviparous pair of lizards (Phrynocephalus przewalskii and Phrynocephalus vlangalii) to examine these transitions. Expression patterns of maternal oviduct through reproductive development of the egg and embryo differ markedly between the two species. We found changes in expression patterns of appropriate genes that account for each of the major aspects of the oviparity to viviparity transition. In addition, we compared the gene sequences in transcriptomes of four oviparous-viviparous pairs of lizards in different genera (Phrynocephalus, Eremias, Scincella, and Sphenomorphus) to look for possible gene convergence at the sequence level. We discovered low levels of convergence in both amino acid replacement and evolutionary rate shift. This suggests that most of the changes that produce the oviparity-viviparity transition are changes in gene expression, so occasional reversals to oviparity from viviparitymay not be as difficult to achieve as has been previously suggested.