The Y chromosome may be a symbol of masculinity, but it is becoming increasingly clear that it is anything but strong and enduring. Although it carries the “master switch” gene, SRY, that determines whether an embryo will develop as male (XY) or female (XX).
The male Y chromosome has degenerated rapidly, leaving females with two perfectly normal X chromosomes, but males with an X and a shrivelled Y. If the same rate of degeneration continues, the Y chromosome has just 4 million years left before it disappears completely. This may sound like a long time, but it isn’t when you consider that life has existed on Earth for 3.5 billion years.
Learn More: Sorry, Guys: Your Y Chromosome May Be Doomed
