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Molecular genetics & endocrinology are fields that do much research & publishing on the subject of mammalian (incl. human) development. This includes a focus on sex determination & sexual differentiation. This is a great PR pub from 2014 for the interested https://jme.bioscientifica.com/view/journals/jme/53/1/R21.xmlhttps://jme.bioscientifica.com/view/journals/jme/53/1/R21.xml
It is quite a technical paper, but (hopefully) useful & provides clarity on the erroneous notion that all embryos start as female and that sex is determined at conception. The closing remarks in particular, provide confirmation for this 2/n
"During male sex determination, SRY is the master regulator of male sex-determining cascade, and its crucial downstream target gene Sox9 is indispensable for the differentiation of the Sertoli cell lineage and male-specific sex determination molecular cascade" 3/n
"the female sex determination pathway has long been considered as passive ‘default’ pathway of gonadal dev in the absence of SRY. Recent studies have challenged (this) by the presence of Rspo1, Wnt4, Foxl2, & Dax1 as female-specific sex-determining genes during ovarian dev" 4/n
"Several lines of evidence suggest the prevailing view that female fate is the ‘default’ state that is imperfect, and the female sex determination pathway also requires an active involvement of female sex-determining genes." 5/n
"Accumulating evidence suggests that the genetic network underlying sex determination and sex differentiation is far more complex and dynamic than portrayed so far." 6/n
"Male-specific and female-specific sex-determining genes antagonize each other's function to establish and maintain the different supporting cell lineage fates during sex determination and throughout adulthood." 7/n
"During mammalian early fetal development, the indifferent, bipotential gonad first appears as symmetrically paired structures within the intermediate mesoderm." 8/n
"The bipotential gonad later can follow one of two alternative male or female fates and develop as two morphologically and functionally different tissues, a testis or an ovary (Kim & Capel 2006, Wilhelm et al. 2007a,b)." 9/n
"For normal growth and maintenance of the bipotential gonad a few genes are required, including Drosophila empty spiracles homeobox 2 (EMX2), GATA-binding protein 4 (GATA4), Wilms' tumor 1 (WT1), LIM homeobox 9 (LHX9), and steroidogenic factor 1 (SF1)" 10/n
"These genes are now discovered to play definitive roles in the earliest gonadal development and primary sex determination (Brennan & Capel 2004, Sekido & Lovell-Badge 2013)" 11/11
