Posted by Baron Greenback [12.255.181.7 - 12-255-181-7.client.attbi.com] on 22 September 2002 at 00.00.56 ZuluTime:

In Reply to: That's called having the downs..... posted by Hunter on 20 September 2002 at 02.16.46 ZuluTime:

There are a few ways people end up with extra genes. The most common one is being a child of someone that had a Robertsonian Translocation in their genes.

Basically, there's two types of general mutations at the Gene (as opposed to the DNA) level. Either two genes swap information (Reciprocal), or the centromeres of two genes that are similar bond, leaving a "long arm" of the gene sticking out at both ends (robertsonian). Of course, this does not always adversly affect people, as all the information is still correct. However, it can sometimes create an "overactive" gene. This is evidenced by the fact that a fusion between pair 14 and 22 usually causes Leukemia, as the cells normally used for creating blood become overactive to the point of being cancerous.

At any rate, healthy or not, the adult then has 45 chromosomes. When the adult has a child, typically the "extra" gene present in one parent and not the other is transcribed to the child, hence, the child ends up with 47 chromosomes, as opposed to a nice even 46. The "extra" gene has only the traits the abberant parent had.

Where Gender cells are concerned, Hunter's right on the money. Since XXY mutations are normally children of Robertsonian parents, even if the Parent didn't exhibit particularly androus or estrous traits with only their 45 chromosomes, the Child now has an extra "boy-girl" gene, which has the potential to override gender differiantation. While the child will likely be mostly androus or estrous (X, HermaphroX, X; X, HermaphroX Y), it will nonetheless likely have both sexual organs in some capacity. If it's lucky, it will simply end up being masculine with lactating nipples. However, this cannot be stressed, having extra chromosomes is, typically, not a good thing.