The long non-coding RNA, MHM, plays a role in chicken embryonic development, including gonadogenesis

► The long non-coding RNA, MHM, is localised in the nucleus of female chick embryos. ► The antisense MHM strand is also expressed, and has a cytoplasmic localisation. ► Over-expression of MHM causes developmental abnormalities in chicken embryos. ► MHM over-expression disrupts expression of the testis-determining gene, DMRT1. ► MHM over-expression induces bilateral ovarian development in females.