In the Amami spiny rat, the the Sry gene is completely absent; thus, it has evolved a novel, unknown sex-determining mechanism independent of Sry.

In the Amami spiny rat, the Enh14 region is duplicated. The two copies of Enh14 act in concert to upregulate Sox9, which causes the differentiation of the testes. TES, Enh13 and Enh8 are other ...

And then there are so-called spiny rats, which actually fall into two different rodent families. One large taxonomic family is neotropical, with around 80 surviving species ...