An ovotestis is a
gonad with both
testicular and
ovarian aspects.[1][2] In humans, ovotestes are an infrequent anatomical variation associated with
gonadal dysgenesis.[3] The only mammals where ovotestes are not symptomatic of a disorder are
moles, wherein females possess ovotestes along with a masculinized
clitoris. These ovotestes in nonpregnant female moles secrete eight times as much testosterone as the ovotestes of pregnant moles.[4] In invertebrates that are normally
hermaphroditic, such as most
gastropods (snails and slugs) in the clade
Eupulmonata, an ovotestis is a common feature of the reproductive anatomy.
In mice, ovotestes are structured such that the central region is testicular tissue while the poles both contain ovarian tissue. Experiments involving the
SOX9 gene, which is initiated by the
SRY region of the Y chromosome, have shown the gene's requirement for testicular differentiation from the presence of ovotestis formation within XX Sox9 trangenic mice. (6) Ovotestis within B6-XYPOS mice allow for gonadal development research within the same tissue to take place in ways previously unavailable.[5][6]
^Gregoire EP et al. (2011). “Transient development of ovotestes in XX Sox9 transgenic mice.” Dev Biol. 394(1):65-77
^Wilhelm D, Washburn LL, Truong V, Fellous M, Eicher EM, Koopman P. Antagonism of the testis- and ovary-determining pathways during ovotestis development in mice. Mechanisms of Development. 2009;126(5-6):324-336.