STANFORD UNIVERSITY MEDICAL CENTER PALO ALTO, CALIFORNIA DEPARTMENT OF GENETICS JcEool of ilfedxine August 28, 1961 DAwnport I-,?oo Cables STANMED Dr. Peter Sneath bdical Rosearch Council National Inrtltute for Hedtcal Research The Ridgeway, Hill HI11 London, N.W. 7, England Dear Peter: This reply to your letter of 9 3une 1s probably far too late to be consquentia! for the paper on eplsomes, but ln any case, my cammnts would be mainly for your interest, and would hardly be likely to evoke a strenuous effort at a revision though you may wlrh to uso your own judgment about this. Let me answer anothor potnt flrst of all, that XV2 is now doubtless much bettor to find In Jscob~s system than was the )c2 of our earlier work, and since so much genetic work has been done with the Parls strains, I belleva that 1 would recamend that you use thaa for any further devolopnents, In our own early work we did not have the analytical techntques by which we might have distlngulshed different variants of the V2 phenetype. Hay I note also that the address of our doparttnent is in the medical school at Palo brto, not _ ,riford, Callfornla. To the paper -- o As Jacob will now acknowledge, the term eplscme was rather remarkably rntfclprted by Thaapson. The refarmce to this Is o ppehdod. Page me, 1ysogenIc bacteriophage, line six - the antecedent for "this" might be clsrlfled. Page two, other eplsomes, 1 Ine one - `Vcmwr?' or "tnferred"? Page three, distribution of bacterial o p1sornes. second paragraph, line two - Is it really a dofinltlw characteristic of epismes that they are infectlous? or that they can be removed by ecrldine? Perhaps I am Interpreting the term "tomnon" too strfngmtly. Page four, second paragraph, RNA episaaes - I don't see the hnpllcatlon that epismer can also contain RNA since Ztnder's phage has by no means been proven to be o pisanlc. This is, of course, an interesting posslblllty, 2 Dr. Peter Sneath August 28, 1961 The nusbor of episclaes per ceil, line two - %na episcaee in the celli' - perhaps in the nucleus or chromosome, but the cell mey contain several of these. Page five - Adsiberg has soma more recent evidence on phosphorous starved F+ cells, that they 8re resdily disinfected by the contagion of F; from which he concludes that under these cond1tiono there is one F particle per cell. He believes that there may also be a more definite regulation in the segregation of the determinants. There is also an interesting note on this point in a recent issue of the Canadian dourn of Senetlcs and Cytology, I believe by dames. Effective episomes on the cell, llno four - i do not accept that Heecacaro and Colombo had demmstrated a surfece antigen characteristic of male cells. They had shown that such cells were more agglutinable by colt entisera. They did, of course, themselves, make the claim which I would here c