I am indebted to Dr. M. J. Murray for indispensable help in making the records to be reported here.
1. The order of br f - as noted in the News Letter of 1940, page 17, Bryan (News Letter 1938, page 5) had questioned the published order of the genes br and f. My report of last year was not wholly satisfactory because I was obliged to limit it to plants recorded as f. The records reported here were made last summer and are taken mostly from 5-point tests involving br f an and, in addition, gs or bm2 and another chromosome-1 gene or translocation. They are assembled here for more ready reference as 3-point tests (items 1 and 2 below)
|1||br f an||512-376||26-25||78-125||12-3||1157|
|2||br f an||1109-853||26-44||92-73||7-2||2206|
|3||br f an||347||22||77||7||453||N.L.'4O, p.17|
|4||br f an||760||40||156||1||960||L.S.'35, p.35|
|1-4||br f an||3957||183||601||35||4776|
|5||br f ad||975||47||141||3||1166||L.S.'35, p.35|
|6||as br f||263||93||21||0||377||L.S.'35, p.35|
|7||br f Kn||446||21||148||25||640||N.L.'38, p. 5|
Item 2 (above) includes cultures involving translocations which apparently reduced crossing over. Both lots indicate the order to be br f an. Results reported in last year's News Letter (item 3) and various records published in the Linkage Summary (items 4-6) are included for comparison. The locus of ad is very near that of an and, therefore, to the right of br as is Kn also, while as is certainly to the left of br. Bryan's records are repeated in item 7.
It is obvious from these records that, in my material, f is to the right of br. Bryan's records do not agree with mine, but they are not wholly conclusive, because, on the assumption of either order of br f, the double crossovers are so nearly equal to the single crossovers in the short region.