Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre (EBC), Science for Life Laboratory, Uppsala University, SE-752 36, Uppsala, Sweden.
Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands.
Nat Commun. 2019 Nov 29;10(1):5468. doi: 10.1038/s41467-019-13427-4.
In some eukaryotes, germline and somatic genomes differ dramatically in their composition. Here we characterise a major germline-soma dissimilarity caused by a germline-restricted chromosome (GRC) in songbirds. We show that the zebra finch GRC contains >115 genes paralogous to single-copy genes on 18 autosomes and the Z chromosome, and is enriched in genes involved in female gonad development. Many genes are likely functional, evidenced by expression in testes and ovaries at the RNA and protein level. Using comparative genomics, we show that genes have been added to the GRC over millions of years of evolution, with embryonic development genes bicc1 and trim71 dating to the ancestor of songbirds and dozens of other genes added very recently. The somatic elimination of this evolutionarily dynamic chromosome in songbirds implies a unique mechanism to minimise genetic conflict between germline and soma, relevant to antagonistic pleiotropy, an evolutionary process underlying ageing and sexual traits.
在一些真核生物中，生殖系和体细胞基因组在组成上有很大的不同。在这里，我们描述了一种主要的由生殖系限制的染色体（GRC）引起的生殖系-体差异，这种差异存在于鸣禽中。我们表明，斑胸草雀的 GRC 包含超过 115 个基因，与 18 条常染色体和 Z 染色体上的单拷贝基因平行，并且富含参与雌性性腺发育的基因。许多基因可能具有功能，这可以从 RNA 和蛋白质水平上在睾丸和卵巢中的表达得到证明。利用比较基因组学，我们表明，基因已经在数百万年的进化过程中被添加到 GRC 中，胚胎发育基因 bicc1 和 trim71 可以追溯到鸣禽的祖先，而数十个其他基因则是最近才被添加的。鸣禽中这种进化上动态的染色体的体细胞消除意味着存在一种独特的机制，可以最小化生殖系和体细胞之间的遗传冲突，这与拮抗多效性有关，拮抗多效性是衰老和性特征的一个进化过程。
