, there is usually a good copy on the other X. So half of the cells responsible are expressing the appropriate gene, which is enough for the clotting system to at least function. Guys aren't so lucky - if your mother gave you a 'bad' X chromome, you've had it.  And it's not just heamophillia - colour blindness, some types of muscular dystrophy and a syndrome that means that you can't eat fava beans (Hannibal Lecter was clearly not a sufferer).  So are there any genes that exist on the Y chromosome but not on the X (other than the obvious!)? Well, we guys are occassionally blessed with the 'hairy ears' gene.  All of this can, of course, become much more complciated. Sufferers of the somewhat seedy sounding 'XXX Syndrome' have, you guessed it, three X chromosomes. Which means that two inactivated X chromosomes exist in every nucleic cell!

Women Are Mosaics

The cells of all female mammals have a bit of an identity crisis going on – half with one way of going about things, half with another. It’s all due to X-chromosome inactivation ….

wild type and peloric fig 2


My PhD programme has us study a wide range of theory and apllied science. It was tough going reading up on a new field every few weeks, but I got alot out of it. Here’s an essay that I wrote as part of a module on ‘Biological Complexity’.   “The need for complexity science when …