Submitted to: Current Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2000
Publication Date: 1/23/2001
Citation: Brown, S., Fellers, J.P., Shippy, T., Denell, R., Stauber, M., Schmidt-Ott, U. 2001. A strategy for mapping bicoid on the phylogenetic tree. Current Biology. 11:R43-44. Interpretive Summary: In insects certain gene regions are used to estimate a time in history when a species changed or diverged. The Biocid protein (bcd) is one of these. The DNA sequence of bcd regions of the fruit fly, cyclorrhaphan blowflies and red flour beetle were compared. Sequence analysis suggests that gene order in this region has been maintained for over 300 million years. Also, ,the bcd replaced a function of another developmental protein in a common ancestor.
Technical Abstract: In Drosophila, a gradient of Bicoid protein (BCD) originates from prelocalized mRNA at the anterior pole of the egg and establishes development programs including those for the larval head and thorax in a concentration-dependent manner. BCD encodes a homeodomain-containing transcription factor. We tested the linkage of bcd and zen in the blowflies Calliphor erythrocephala and Lucilia sericata, and red flour beetle Tribolium castaneum by sequence analysis. It was found that orthologs of eight arthropod homeotic genes were arrayed in the same order as the Drosophila counterparts for over 300 million years. In Tribolium, there is a second zen gene immediately downstream of the one previously identified. This suggests that BCD functionally replaced an ancestral anterior determinant.