The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China.
Department of Neuroscience and Developmental Biology, University of Vienna, 1030 Vienna, Austria.
Genes (Basel). 2021 Nov 15;12(11):1796. doi: 10.3390/genes12111796.
The origin of functional new genes is a basic biological process that has significant contribution to organismal diversity. Previous studies in both and mammals showed that new genes tend to be expressed in testes and avoid the X chromosome, presumably because of meiotic sex chromosome inactivation (MSCI). Here, we analyze the published single-cell transcriptome data of adult testis and find an enrichment of male germline mitotic genes, but an underrepresentation of meiotic genes on the X chromosome. This can be attributed to an excess of autosomal meiotic genes that were derived from their X-linked mitotic progenitors, which provides direct cell-level evidence for MSCI in . We reveal that new genes, particularly those produced by retrotransposition, tend to exhibit an expression shift toward late spermatogenesis compared with their parental copies, probably due to the more intensive sperm competition or sexual conflict. Our results dissect the complex factors including age, the origination mechanisms and the chromosomal locations that influence the new gene origination and evolution in testes, and identify new gene cases that show divergent cell-level expression patterns from their progenitors for future functional studies.
功能新基因的起源是一个基本的生物学过程，对生物多样性有重要贡献。先前在 和哺乳动物中的研究表明，新基因往往在睾丸中表达，并避免 X 染色体，这可能是由于减数分裂性染色体失活（meiotic sex chromosome inactivation，MSCI）。在这里，我们分析了已发表的 成年睾丸单细胞转录组数据，发现 X 染色体上的有丝分裂基因富集，而减数分裂基因减少。这可以归因于来自其 X 连锁有丝分裂前体的常染色体减数分裂基因的过剩，这为 中的 MSCI 提供了直接的细胞水平证据。我们揭示了新基因，特别是那些由逆转座产生的新基因，与它们的亲本拷贝相比，往往在后期精子发生中表现出表达转移，这可能是由于更强烈的精子竞争或性冲突。我们的研究结果剖析了影响睾丸中新基因起源和进化的复杂因素，包括年龄、起源机制和染色体位置，并确定了新基因的案例，这些基因与它们的前体相比，在细胞水平上表现出不同的表达模式，为未来的功能研究提供了线索。
