From crosby@XXXX Thu Jan 07 19:57:33 1999 To: flybase-updates@XXXX Subject: pc regarding yellow constructs To: FlyBase From: Francois Huet, Madeline Crosby, Ryan Baugh We wish to report as a personal communication the following information regarding pP{Car20y} and derived constructs. It has been previously reported (Nassif et al., 1994, MCB 14:1613 ) that the SalI y+ segment derived from pP{Car20y} is not 7.7kb as originally claimed, but approximately 7.9kb. It was established by Nassif et al. that the extra ~200bp are at the 3' end of the yellow segment. Using several constructs derived from pP{Car20y}, we have confirmed these results and have sequenced the unidentified fragment. The sequence is presented below, starting with the BglII site known to be at the 3'end of yellow, and ending with the SalI site used to clone into and out of pP{Car20y}. 19bp at the 3'end appear to be derived from a polylinker; the first 157bp are identical to sequence located 1.7kb downstream from the yellow fragment in cosmid clone DMC125H10 (accession number AL023873; 21264-21420). Ligation of the yellow fragment with the 157bp fragment appears to have occurred at the BglII site at the 3' end of yellow and the BglII site at the 5' end of the 157bp fragment. A new BamHI site has been created at 163-168. Sequence: agatcttgtt tgggtgcagg gaaagttcaa cttaatcgct caatttgaga tcgcctggtc gcttgagatt cgactgtaat tgaaattttt gcttttgatc ggagccagac ttcagacggg gcaaacaaaa agactttgtt ggtggtaggg taggatccgt tgacctgcag gtcgac This extra fragment may also be present in mini-yellow and other constructs derived from pP{Car20y}. From rd120@XXXX Fri Jan 08 13:55:17 1999 To: crosby@XXXX Subject: Re: pc regarding yellow constructs Hi Lynn, It seems sensible to rename the allele y+t7.9. Do you suppose it also corresponds to y+t8? From crosby@XXXX Fri Jan 08 15:31:50 1999 To: rd120@XXXX Subject: Re: pc regarding yellow constructs Rachel, >It seems sensible to rename the allele y+t7.9. Do you suppose it >also corresponds to y+t8? I believe they are all the same thing (this finding nicely explains the discrepancies). HOWEVER, y+t7.7 is the more correct symbol -- the extra 170bp may not be related to yellow. I think it must be due to some sort of cloning glitch; it is an apparently random fragment about 1.7kb away, probably present in the original genomic clone. y+t7.9 and y+8 are truly incorrect -- since the sequence order is not as found in the wild type. \--Lynn