Question: Is it true that man's Y chromose is gradually become shorter?

Lilian Hunt answered on 12 Mar 2014:

Over our individual lives, all our chromosomes actually get a bit shorter. This is because on the ends of them there are bits called ‘telomeres’ that are there to protect all the important bits of DNA each time a cell replicates. They have a little chopped off each time to make sure that the actual important DNA doesn’t get any chopped off itself!

Man’s Y chromosome is tiny, so when some researchers found that over evolution it has shrunk people started getting concerned that it would keep shrinking and eventually disappear! Over 300 million years, it has lost 1393 genes so people predicted that in another 10million years it would lose the rest too. However we now know that since 6-7million years ago (when humans and chimps evolved into their separate species) the Y chromosome hasn’t got any smaller. Also, we worked out that it has only lost one gene since 25million years ago so it seems that this shrinking of the Y chromosome has either stopped or slowed down significantly to not worry us for now…!