From The Star:
Researchers have pieced together strong evidence as to why women are born tougher than men.
Science has long believed the “male flu,” or men’s higher susceptibility to infections, colds and disease, is real. The reasons pointed to the basic genetic difference: two X chromosomes in women and one X and one Y in men.
Now molecular biologists at the University of Ghent in Belgium have looked inside those genes and found the microRNA molecules, one of the most important regulatory mechanisms in human cells, could very well explain the difference.
“The microRNA field is quite a new field,” Dr. Iris Pinheiro told the Toronto Star on Thursday. “What is remarkable about the X chromosome is that it has so many microRNAs.”
And what is so remarkable about the Y chromosome is that it has none.
“That is striking to me,” said Pinheiro. The Y chromosome has evolved through history to shed almost all of its important genes and now has only one biological function: to make men male and to produce sperm.
Scientifically, she said, “it’s just a piece of junk DNA.”