Turtle embryos become male or female according to epigenetic controls - clues to human development
Life unfolds to a blueprint written in our DNA, but our environment also plays a huge role in how we develop. The outside world affects molecules surrounding important genes, changing how they’re read or expressed. These epigenetic controls also change as we age, or with some diseases. In red-eared slider turtles, temperature affects the epigenetics around a gene called Kdm6b, which helps to decide their sex. Here a turtle gonad develops into a testicle at 26 degrees (left), yet by blockingKdm6b either with genetic engineering (middle) or by turning up the heat to 32 degrees (right), the turtle develops ovaries instead. Red fluorescence highlights the turtle’s own future sex cells – sperm or eggs. Although temperature doesn’t affect mammalian sex determination, these turtles offer a peek at how epigenetics works during development, providing clues to changes in human development that go beyond our genes.
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