Ohana Biosciences, Cambridge, MA, USA.
Center for Immunology and Inflammatory Diseases, Center for Cancer Research, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
Science. 2021 Mar 5;371(6533). doi: 10.1126/science.abb1723. Epub 2021 Jan 14.
Sperm are haploid but must be functionally equivalent to distribute alleles equally among progeny. Accordingly, gene products are shared through spermatid cytoplasmic bridges that erase phenotypic differences between individual haploid sperm. Here, we show that a large class of mammalian genes are not completely shared across these bridges. We call these genes "genoinformative markers" (GIMs) and show that a subset can act as selfish genetic elements that spread alleles unevenly through murine, bovine, and human populations. We identify evolutionary pressure to avoid conflict between sperm and somatic function as GIMs are enriched for testis-specific gene expression, paralogs, and isoforms. Therefore, GIMs and sperm-level natural selection may help to explain why testis gene expression patterns are an outlier relative to all other tissues.
精子是单倍体，但必须在功能上等效，以便在后代中平等分配等位基因。因此，通过精细胞细胞质桥共享基因产物，消除了个体单倍体精子之间的表型差异。在这里，我们表明，一大类哺乳动物基因在这些桥接中并没有完全共享。我们将这些基因称为“基因信息标记”（GIMs），并表明其中一部分可以作为自私的遗传元素，在鼠、牛和人群中不均匀地传播等位基因。我们发现，为了避免精子和体细胞功能之间的冲突，存在进化压力，因为 GIMs 富含睾丸特异性基因表达、同源基因和异构体。因此，GIMs 和精子水平的自然选择可能有助于解释为什么睾丸基因表达模式相对于所有其他组织是一个异常值。
