A new development in genetic research has uncovered yet another mechanism for male sexual differentiation without a Y chromosome.
Adelaide researchers have discovered a way of creating a male mouse without a Y chromosome by activating a single gene, called SOX3, in the developing fetus. SOX3 is known to be important for brain development but has not previously been shown to be capable of triggering the male pathway. …
Associate Professor Thomas and his colleagues have generated male mice with two X chromosomes by artificially activating the SOX3 gene in the developing gonads.
“These XX male ‘sex reversed’ mice are completely male in appearance, reproductive structures and behavior, but are sterile due to an inability to produce sperm,” he says.
In the popular mind, “science” says chromosomes define your sex. But ongoing research in molecular genetics is increasingly showing this to be a crude and oversimplified version of the truth. But when the facts consistently run against popular beliefs, eventually those beliefs are destined to change.
And lest we doubt that this research says something about the mouse’s bipedal, house-ape cousins, the researchers note…
Further collaborative research with Professor Andrew Sinclair at the Murdoch Children’s Research Institute in Melbourne and Professor Eric Vilain at UCLA (University of California Los Angeles) has also shown that changes in the human SOX3 gene are present in some individuals who are XX males.
“From a genetic perspective, cases of XX male sex reversal are particularly intriguing and are poorly understood,” Associate Professor Thomas says.
“This discovery provides new insight into the genetic causes of disorders of sexual development, which are relatively common in the community.
“For the future, this discovery will impact on the molecular diagnosis of these disorders and, ultimately, help us to develop therapies or technologies to improve clinical outcomes,” he says.
While some religious and social conservatives urge resistance to abandoning the chromosomal XX = girl, XY = boy formulation, science marches on.
The march of scientific progress doesn’t always leave our pre-conceptions happily intact. Yet it can leave us happier still if we’re willing to show humility toward the facts.
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.
Hamlet Act 1, scene 5, 159–167