Data from: Lineage-independent retrotransposition of UTP14 associated with male fertility has occurred multiple times throughout mammalian evolution

In mammals, gamete production is essential for reproductive success. This is particularly true for males where large quantities of sperm are produced to fertilize a limited number of eggs released by the female. Because of this, new genes associated with increased spermatogenic efficiency have been accumulating throughout the evolution of therian mammals. Many of these new genes are testis-specific retrotransposed copies of housekeeping genes located on the X chromosome. Of particular interest are retrotransposed copies of UTP14 that are present in many distantly related eutherian mammals. Analysis of genomic data available in ENSEMBL indicates that these UTP14 retrogenes have arisen independently in the various eutherian clades. They represent an interesting aspect of evolution whereby new homologues of UTP14 have become independently fixed in multiple mammalian lineages due to the reproductive advantage that may be conferred to males. Surprisingly, these genes may also be lost, even after being present within a lineage for millions of years. This phenomenon may potentially be used to delineate evolutionary trees in closely related groups of mammals, particularly in the case of South American primates. Studying these retrogenes will yield new insights into the evolutionary history of male gamete production and the phylogeny of eutherian mammals.在哺乳动物中，配子生成对于繁殖成功至关重要。这一点在雄性个体中尤为关键：雄性需产生大量精子，以完成对雌性释放的有限数量卵子的受精过程。正因如此，与精子发生效率提升相关的新基因在兽亚纲哺乳动物的演化历程中持续积累。此类新基因中，多数为定位于X染色体的持家基因的睾丸特异性逆转座拷贝。尤为值得关注的是，在诸多亲缘关系较远的真兽亚纲（Eutherian）哺乳动物中均存在UTP14的逆转座拷贝。通过对Ensembl数据库公开基因组数据的分析可知，这些UTP14逆转录基因在不同的真兽亚纲演化支中独立起源。它们展现了演化过程中一则有趣的现象：由于可赋予雄性繁殖优势，UTP14的新同源基因在多个哺乳动物演化支系中被独立固定下来。令人意外的是，即便在某一演化支系中存续了数百万年，这类基因也可能发生丢失。这一现象或可用于厘清亲缘关系较近的哺乳动物类群的演化树，尤以南美洲灵长类类群为典型。对这类逆转录基因的研究，将为雄性配子生成的演化历程以及真兽亚纲哺乳动物的系统发育研究带来新的见解。