Robert Warren, Lisa Nagy, Jane Selegue, Julie Gates and Sean Carroll carried out this experiment which aimed to examine the expression of homeotic genes in butterflies. The hypothesis they tested was: Did homeotic genes drive morphological change or do homeotic genes provide a pre-existing blueprint in which insect segment diversity evolved. The Antp, Scr, Abd-A and Ubx genes were isolated from a cDNA library and were used to explore differences in limb and wing number between flies and butterflies. Where Ubx and Abd-A are expressed, limb and wing numbers appear. They began to wonder whether the expression of BX-C genes was different in butterflies (P.Coeni) and fruit flies (Drosophila). When they ran tests, they found that the conservation of expression of the BX-C and ANT-C homeotic genes is fundamentally similar and does not explain the differences in the appendages of each species. They looked at embryogenesis, and in 20% of butterfly embryogenesis, they found that Abd-A protein and RNA are expressed in the anterior and abdominal segments. High levels of Antp expression are observed in the thorax. Beyond the 20% embryogenesis mark, the observed patterns of Abd-A, DII, and Antp expression differed extremely: no DII or Antp was expressed in the abdominal leg. After seeing this, they tested whether DII was responsible for the down-regulation. from Ubx/Abd-A. They used double-label experiments using antibodies against the butterfly antibodies DII and Ubx/Abd-A and performed them. Activation of DII in proleg trace repression for Ubx and Abd-A expression, which showed repression of the BX-C gene, is the initial event. When DII expression of the abdominal segments of the Drosophila embryo is repressed due to Ubx and Abd-A, the formation of the abdominal limb in the middle of paper......nes to produce different types of structures modeled in the same position. In general, 0 alters the number, size, pattern of homologous structure, and body appendages, implying changes in the timing and spatial regulation of existing genes. In some cases these are homeotic genes and in other cases they are downstream genes. If I were to continue this line of research, I would test and see if there are different hox genes for different animals. I would expect to see some duplication occurring in the lineages within each species. For example, if duplication were to occur at the hox gene (in butterflies, fruit flies, earthworms, etc.), I would expect to see different hox genes. But given the way genes are conserved, that probably wouldn't end up happening. This new test would therefore prove that hox genes are conserved and that each species should have the same hox genes...