Subject: location of gene "clipped" Date: Fri, 21 Jul 2006 14:24:27 -0400 From: "Kennison, James \(NIH/NICHD\) [E]" <kennisoj@XXXX> To: <flybase-updates@XXXX> I have mapped cp distal to asf1 (76C) by meiotic recombination. The cytological location of cp (given as 77A-D) is based on the mistaken belief that Df(3L)rdgC-co2 includes cp. I believe that Df(3L)rdgC-co2 was induced on a marked third chromosome that carried the cp allele. I have separated cp from Df(3L)rdgC-co2 by meiotic recombination. One class of recombinants was Df(3L)rdgC-co2 and cp[+] . The reciprocal class of recombinants was cp, but was not Df(3L)rdgC-co2. The classification of cp[I5] as a gain-of-function allele was also based on the belief that cp was deleted by Df(3L)rdgC-co2 and should be reconsidered. Jim Kennison Jim_Kennison@XXXX NICHD, NIH, HHS Date: Mon, 24 Jul 2006 15:43:29 +0100 (BST) From: "Rachel Drysdale (Genetics)" <rd120@XXXX> Subject: Re: location of gene "clipped" To: kennisoj@XXXX Cc: rd120@XXXX Hi Jim, just a follow on question here about what to do for map data for cp, given that cp is not uncovered by Df(3L)rdgC-co2. You say that asf1 (current map location 76B9) lies to the right of cp. However in FBrf0123112 == Lukinova et al., 1999, Genetics 153(4): 1789--1797 it is suggested (by failure of complementation with cp and cp[I5]) that T(2;3)rdgC[co6] causes an allele of cp. The 3L break of T(2;3)rdgC[co6] is thought to be 77B1. This seems to be on the basis of cytological observation, and mapping to rdgC. Given your mapping of cp by recombination, it seems likely that it is not the 77B1 break of T(2;3)rdgC[co6] that is causing the effect on cp, but another case of there being a linked mutation. In fact FBrf0052690 == Steele and O'Tousa, 1990, Neuron 4: 883--890 reports T(2;3)rdgC[co6] and Df(3L)rdgC-co2 coming out of the same screen. So it seems to me (please check my logic) that both T(2;3)rdgC[co6] and Df(3L)rdgC-co2 will carry the same separable cp. In light of this I will make alterations to the T(2;3)rdgC[co6] record too. I believe at this point we have no accurate cytological assessment of the whereabouts of cp (other than to the left of asf1), but a definite unknown is more valuable than a false known. Best regards, Rachel. Subject: RE: location of gene "clipped" Date: Mon, 24 Jul 2006 14:53:16 -0400 From: "Kennison, James \(NIH/NICHD\) [E]" <kennisoj@XXXX> To: "Rachel Drysdale \(Genetics\)" <rd120@XXXX> Rachel, I would agree that T(2;3)rdgC[co6] was also induced on a chromosome that already carried cp. We know that cp maps between st and asf1. It complements Df(3L)81k19 [73A;74F] and Df(3L)kto2 [76B1-2;76D5], which uncover st and asf1, respectively. That places cp between 74F and 76B. Lindsley and Zimm (1992) claim that cp is proximal to the 75D4-5 breakpoint of T(Y;3)L131 (according to V. Walker). Jim Date: Tue, 25 Jul 2006 09:48:41 +0100 (BST) From: "Rachel Drysdale (Genetics)" <rd120@XXXX> Subject: RE: location of gene "clipped" To: rd120XXXX, kennisojXXXX Thanks Jim, will add your further info to the pc I yesterday added the V. Walker 'proximal to 75D4-5' mapping to the gene record for clipped, however this is unsatisfactory because the source (method) is not terribly clear - I just cited Lindley and Zimm as the source. The further information you provide below is much better thank you - though we have just missed a cut off for an update so unfortunately it will have to wait until the next round to get to the public pages. Thanks again for your help, Rachel.