EXTINCTION OF MEN : A MYTH OR A REALITY ?
The Y chromosome is a never-ending source of fascination particularly to men because it bears genes that determine maleness & make sperm. It’s also small & seriously weird; it carries few genes and is full of junk DNA that makes it horrendous to sequence. The sex of human & other mammal babies is decided by a male-determining gene on the Y chromosome. But the human Y chromosome is degenerating and may disappear in a few million years, leading to our extinction unless we evolve a new sex gene. However two branches of rodents have already lost their Y chromosome and have survived successfully. In humans, as in other mammals, females have two X chromosomes and males have a single X and a puny little chromosome called Y. The names have nothing to do with their shape; the X stood for “unknown”. The X contains about 900 genes that do all sorts of jobs unrelated to sex. But the Y contains few genes (about 55) and a lot of non-coding DNA – simple repetitive DNA that doesn’t se...