Evolution of the testis-determining gene--the rise and fall of SRY.
Evolution of the testis-determining gene--the rise and fall of SRY.
复制标题
睾丸决定基因的进化——SRY的兴衰.
作者：
J. Graves
人们很早就知道哺乳动物的 Y 染色体含有触发睾丸决定的基因，这种睾丸决定因子在 1990 年被鉴定为 SRY。人们认为 SRY 是最初的哺乳动物性别决定基因，在哺乳动物进化的早期启动了 Y 与 X 的分化，并且通过对分化时间的分析，这一观点得到了加强。然而，我在这里要争论的是，SRY是最近在兽类哺乳动物中进化出来的，并不是定义X和Y的原始哺乳动物性别决定基因。它是X传播的SOX基因的降解版本，更适合成为大脑决定基因。它在性别决定中没有核心作用，可以作为触发因素被替换或丢失，就像最近进化史上的许多其他 Y 基因一样。鼹鼠显然已经做到了这一点。
The mammalian Y chromosome has been known for a long time to harbour a gene that triggers testis determination, and this testis-determining factor was identified as SRY in 1990. It has been supposed that SRY was the original mammalian sex-determining gene that initiated the differentiation of the Y from the X early in mammalian evolution, and this belief has been reinforced by an analysis of divergence times. However, I will argue here that SRY evolved quite recently in therian mammals and was not the original mammalian sex-determining gene that defined the X and Y. It arose as a degraded version of the X-borne SOX gene that is better qualified to be a brain-determining gene. It has no central role in sex determination, and can be replaced as a trigger and lost, as have many other Y-borne genes in recent evolutionary history. The mole vole has evidently accomplished this.