The molecular genetics of ovarian differentiation in the avian model

K. L. Ayers, A. H. Sinclair, C. A. Smith

Research output: Contribution to journalReview ArticleResearchpeer-review

43 Citations (Scopus)


In birds as in mammals, sex is determined at fertilization by the inheritance of sex chromosomes. However, sexual differentiation - development of a male or female phenotype - occurs during embryonic development. Sex differentiation requires the induction of sex-specific developmental pathways in the gonads, resulting in the formation of ovaries or testes. Birds utilize a different sex chromosome system to that of mammals, where females are the heterogametic sex (carrying Z and W chromosomes), while males are homogametic (carrying 2 Z chromosomes). Therefore, while some genes essential for testis and ovarian development are conserved, important differences also exist. Namely, the key mammalian male-determining factor SRY does not exist in birds, and another transcription factor, DMRT1, plays a central role in testis development. In contrast to our understanding of testis development, ovarian differentiation is less well-characterized. Given the presence of a female-specific chromosome, studies in chicken will provide insight into the induction and function of female-specific gonadal pathways. In this review, we discuss sexual differentiation in chicken embryos, with emphasis on ovarian development. We highlight genes that may play a conserved role in this process, and discuss how interaction between ovarian pathways may be regulated. 

Original languageEnglish
Pages (from-to)80-94
Number of pages15
JournalSexual Development
Issue number1-3
Publication statusPublished - 2013
Externally publishedYes


  • Chicken embryo
  • FOXL2
  • Ovary
  • R-spondin 1
  • Sexual differentiation

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