In article <gcamp1-240494125833 at mac11.whartonef1.swarthmore.edu>, gcamp1 at cc.swarthmore.edu (Geoff Camp) writes:
> I was talking with a group of people about people whose XY chromosomes are
> "screwy," like XXY, etc, and someone recalled hearing about men who were
> for some reason EXTRA-masculine. That is to say, they were very hairy and
> extremely aggressive, very MALE. We wondered if it were in ANY way
> possible to get an set of chromosomes that were XYY, or how genetically
> this could happen. Could someone be XYY, or maybe just Y ? Thanks in
> advance to anyone who answers!
>> Geoff Camp
About 1 male in 1000 has an extra Y chromosome This arises during
the develpment of the sperm (second meiotic division) so that a sperm with
two Y chromosomes is produced. The vast majority of cases appear quite
normal, although the men are taller than average. There has been
considerable controversy over the possible behavioral manifestations, but
again the majority of XYY males function quite normally in society.
A "Y only" embryo will not survive, since there are many essential
genes on the X-chromosome that are not found on the (much smaller) Y.
Roger C. Green, Faculty of Medicine Phone: (709)737-6884
Memorial University , St. John's, Newfoundland FAX : (709)737-7010