Subject: Notes on P{XP}d06981 and Df(3R)Exel6176 Notes on P{XP}d06981 and Df(3R)Exel6176 Kevin Cook and Annette Parks The following concerns Df(3R)Exel6176 (FBab0038231). It was generated by FLP-mediated recombination between P{XP}d06981 (FBti0056296) and P{XP}d05816 (FBti0042831). The mapping of P{XP}d05816 is uncomplicated, but the mapping of P{XP}d06981 is problematic. Exelixis analyzed the sequence flanking P{XP}d06981 on three different occasions. One sequence read mapped the P{XP}d06981 insertion to Release 3 coordinate 3R:12879395 . A second read mapped P{XP}d06981 to 3R:19043238 . A sequence read from the proximal side of the recombined P{w+mC=XP-U}Exel6176 insertion associated with Df(3R)Exel6176 mapped it to 3R:12879384 . These results suggest that the 3R:19043238 position is incorrect and represents a sample tracking error of some kind. A complementation test at Bloomington showed that Df(3R)Exel6176 (Release 3 predicted cytology 89E11;89F1) failed to complement Df(3R)ED5780 (Release 4 predicted cytology 89E11;90C1) as one would predict for overlapping deletions. This further suggests that 3R:12879384..12879395 is the correct position of P{XP}d06981. Genbank accession CZ475462.1 corresponds to the sequence read that placed P{XP}d06981 at 3R:19043238 , but it may correspond to the sequence flanking some other insertion.