lpetrich

Here's a <a href="http://www.cc.ndsu.nodak.edu/instruct/mcclean/plsc731/flower/flower3.htm" target="_blank">nice page</a> on that subject, discussing mostly work on Arabidopsis flowers, but nevertheless likely to be more general, as work on Drosophila has been.

There are three sets of genes which control flower-part fate, which have been named A (apetala1 and apetala2), B (apetala3 and pistillate), and C (agamous). Here is how they are associated with which part:
[code]
A . . - Sepals
A B . - Petals
. B C - Stamens
. . C - Carpels (Pistil Parts)
</pre>[/quote]
Mutations in these genes can cause flower parts to develop like parts from the wrong places -- loss of B genes causes petals to develop like sepals and stamens like carpels, and loss of all of them makes all parts develop like "normal" leaves.

If this modus operandi seems familiar, you are right. These ABC genes work much like the animal kingdom's homeobox (Hox) genes, but they have a completely separate origin, being "MADS-box" instead. Thus being a good example of convergent evolution.

[ July 05, 2002: Message edited by: lpetrich ]</p>