Gonad Differentiation in the Rabbit: Evidence of Species-Specific Features

Abstract

The rabbit is an attractive species for the study of gonad differentiation because of its 31-day long gestation, the timing of female meiosis around birth and the 15-day delay between gonadal switch and the onset of meiosis in the female. The expression of a series of genes was thus determined by qPCR during foetal life until adulthood, completed by a histological analysis and whenever possible by an immunohistological one. Interesting gene expression profiles were recorded. Firstly, the peak of SRY gene expression that is observed in early differentiated XY gonads in numerous mammals was also seen in the rabbit, but this expression was maintained at a high level until the end of puberty. Secondly, a peak of aromatase gene expression was observed at two-thirds of the gestation in XX gonads as in many other species except in the mouse. Thirdly, the expression of STRA8 and DMC1 genes (which are known to be specifically expressed in germ cells during meiosis) was enhanced in XX gonads around birth but also slightly and significantly in XY gonads at the same time, even though no meiosis occurs in XY gonad at this stage. This was probably a consequence of the synchronous strong NANOS2 gene expression in XY gonad. In conclusion, our data highlighted some rabbit-specific findings with respect to the gonad differentiation process.

Models of Intrauterine growth restriction and fetal programming in rabbits

“…Regarding sexual organ development in the rabbit, the first germ cells in both females and males can be found from GD9 (Daniel‐Carlier et al, ) and the gonads of both sexes are evident from GD14 (Bernier & Beaumont, ; Daniel‐Carlier et al, ). Female rabbits initiate the process of oogenesis at birth, with the oogonia entering meiosis during the first 10 days (Hutt, McLaughlin, & Holland, ).…”

“…Three weeks after birth, both primordial and developing follicles can be observed in the ovary with the first detectable antral follicles by 12 weeks old (Hutt et al, ). On the other hand, testicular differentiation in the male occurs at GD16, in which germ cells can be differentiated from mesenchymal cells (Gondos & Conner, ) and initiate meiosis by PND50 (Daniel‐Carlier et al, ; Wartenberg, Kinsky, Viebahn, & Schmolke, ). Testis descent commences around PND6 and is completed by PND22.…”

“…Regarding sexual organ development in the rabbit, the first germ cells in both females and males can be found from GD9 (Daniel-Carlier et al, 2013) and the gonads of both sexes are evident from GD14 (Bernier & Beaumont, 1964;Daniel-Carlier et al, 2013).…”

Characterization of Embryonic and Fetal Development of Necromys Lasiurus (Rodentia, Cricetidae)

“…These two families are the most abundant of the order Rodentia. Published data on embryology and organogenesis can be found for these groups [8][9][10][11][12], as well as for histricomorph rodents [13][14][15][16][17]; and related species such as the rabbit (Oryctolagus cuniculus) [18][19][20][21].…”

Investigating the role of BCAR4 in ovarian physiology and female fertility by genome editing in rabbit

“…In this species, meiosis is initiated at birth in the female gonad. Primordial follicles assemble two to three weeks post-partum (wpp); they can initiate growth around 4 wpp, and antral follicles are detected by 12 wpp 10,11 . We have therefore characterised BCAR4 expression in the doe.…”