Environmental Factors Can Alter Mammalian Sex Determination, Study Finds

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A groundbreaking study by researchers at Osaka University in Japan has revealed that a mother’s iron deficiency can influence the sex of male offspring in mice, possibly reversing their biological gender. Published in the journal Nature, the study's principal investigator, Makoto Tachibana, stated, “This is the first demonstration that an environmental factor can influence sex determination in a mammal." The research found that a 60% reduction in cellular iron concentration can deactivate the SRY gene, which is crucial for male sexual differentiation.

In experiments, six out of 39 XY male mice developed into females with fully formed ovaries, while another displayed intersex characteristics. The findings suggest that low iron levels impact the enzyme KDM3A, altering epigenetic regulation during critical developmental windows. Experts like Francisco Javier Barrionuevo from the University of Granada emphasized the study's significance, noting that such external factors could lead to unrecognized cases of sex reversal in extreme malnutrition scenarios in humans. The implications pose crucial questions about maternal health and fetal development in mammals.

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