How come geneticists aren't able to mutate a human's DNA to have two y chromosomes? Well, first of all have they tried, and if they have and it didn't work, how come?

Question

anonymous · Answer

I'm guessing there's a lot of really important stuff on the X chromosome that isn't on the Y chromosome, so you need at least one X.

anonymous · Answer

I just looked on Wikipedia, and it turns out there are 1,846 genes on the X chromosome and only 454 	on the Y chromosome.

anonymous · Answer

The Y chromosome really isn't that important anymore. Compared to the X chromosome, it does close to nothing, and the X chromosome is VERY important. There is only one important gene on it, and that's the gene to determine if you are male or female. It's called the SRY, or "sex-determining region". The SRY actually works even when it is translocated on to the X-chromosome, so technically a male can have a genotype XX if his SRY gene is present on one of the X's, and this has happened! The Y-chromosome is predicted to gradually disappear from humans, who will then evolve another method of sex determination.

anonymous · Answer

As the posts above have noted, having a YY chromosome most likely kills you.

However, it is possibly to have a XYY chromosome (that's 3 chromosomes), without dying. Generally people with triple chromosomes have unusual features and associated genetic diseases, but they still exist.

anonymous · Answer

Huh, that's interesting...Have they ever tried to make one with a double Y before, though?