For the right portion of the chromosome, where we don't have a high density of mapped mutants, we are using the PCR mapping protocol of Barstead and Waterston (in 1991 C Mot Cyto 20:69) to position gamma-induced lethals (potential deletions). Using
hIn1 as a balancer (Zetka and Rose, 1992 Genetics), we recovered several lethals linked to
unc-101 and
lev-11 which were induced with 1500 rads of gamma radiation. Primers were kindly provided by Junho Lee in Paul Sternberg's lab and Yuko Kozono in Bob Waterstons's lab. As controls for the PCR reactions, we are using a deletion outside the
hIn1 region, hDf8 ,and primers from
bli-4 (Ken Peters, unpublished) and AHH sequences (Prasad, Starr and Rose, in press). hDf8 deletes AHH, but not
bli-4 .We have tested nine of our gamma induced lethals to date and one of these hDf14 (
h1277 )is lacking DNA for the primer set INT 7-10 from
unc-101 sequences provided by Junho Lee.