Subject: ADRC: 143 Dear Bin and Sidney, I am writing in connection with your abstract for the upcoming Washington DC ADRC: 'High resolution mapping of Drosophila mutations using site-specific male recombination.' John Roote mentioned to me that some of the mapping data for cortex that is presented in your abstract is in error. Please could you confirm that for me, and I will make sure we exclude anything that is potentially confusing. Many thanks for your help, Rachel. Subject: Re: ADRC: 143 Dear Dr. Drysdale: Cortex is now placed distal to black and distal to the 34A region, based on male recombination mapping utilizing additional P elements. Sincerely, Bin and Tehyen