Sex and the single cell

Sex chromosomes in every cell of the body exert widespread and sometimes unexpected effects.

It was the mouse equivalent of the midnight munchies. Instead of sleeping normally, Karen Reue’s lab mice were waking early and nibbling on extra snacks, which was making them obese. On investigation, she was surprised to find that the probable reason for this out-of-hours feeding was the genetic sex of their cells — the number and kind of sex chromosomes they contain. “It wasn’t at all what we expected,” says Reue, a geneticist at the University of California, Los Angeles (UCLA).

“There is a huge consequence to having two X chromosomes versus an X and a Y.

The idea that our body cells have a ‘sex’, and that this property has consequences for our health, has taken biologists by surprise. Experiments performed in the mid-twentieth century had implied that the hormones produced by the ovaries or testes were the source of physiological differences between males and females. But Reue’s findings are part of a growing body of evidence showing that hormones are only part of the story. It now seems that the genetic sex of cells is crucial too. Cellular sex may also help to explain why women and men have different susceptibilities to conditions such as obesity, heart disease, neurodegeneration, autoimmunity and cancer, and why such conditions can behave differently in the two sexes. Certainly, when it comes to metabolism, “there is a huge consequence to having two X chromosomes versus an X and a Y throughout your whole body,” says Reue…

To read more, click here: Nature Outlook article on cellular sex (5th October 2017)



Secrets of life in a spoonful of blood

The intricate development of the fetus is yielding its long-held secrets to state-of-the-art molecular technologies that can make use of the mother’s blood.

Life starts with a puzzle. Out of sight in a mother’s womb, 3 billion letters of DNA code somehow turn into 3D bodies, all in the space of a mere 40 weeks. Fetuses form eyes, brains, hearts, fingers and toes — in processes that are meticulously coordinated in both time and space. Biologists have pieced together parts of this puzzle, but many gaps remain.

Now, a crop of molecular technologies is giving scientists tantalizing hints about how to fill in those gaps. Improved ways of reading and interpreting the information in fetal genetic material are uncovering a raft of genes involved in human development, and letting researchers eavesdrop on the hum of gene activity before birth. They can see which genes turn on or off at pivotal moments, and sense how the environment nurtures or intrudes on this…

Read more on Nature‘s website here.