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}.
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?
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