Brandley Hersh Hox genes and development

Today I took the “T” into Northeastern to hear an excellent seminar on HOX genes and the regulation of development. The organism of interest was drosophila melanogaster with which I once labored in graduate school in the 60s. How things have changed. Back then about all one could due was to breed the fruit flies in milk bottles on banana paste and look at them under a binocular microscope. In this talk, Dr. Hersh was taking genes out and putting them in with reporter molecules that could show just where in the wing bud a gene was active and where it was not. HOX genes are conserved throughout bilaterally symmetric organisms and control the development of many structures. One of the keys of these studies is that the control of when genes are turned on and turned off and not how many genes there are is most important. A simple worm has only half the genes that we possess but we do a much better job of controlling when they are active and when they are inactive. When I was in school it was impossible to examine a whole genome to determine which genes are turned off or turned on in a specific structure such as a wing bud. Today it is a matter of course. The speaker showed examples of numerous flies that had been genetically engineered to contain specific nucleotide sequences that aided in his evaluation of the control mechanisms. It just isn’t fare that it was so difficult back then and so “easy” today.