Rick, C. M.
Dr. Young's Curly (Cu) mutant has been used in a series of exploratory linkage tests. With us it has performed as a very satisfactory seedling mutant. No clue for the phenotypic separation of Cu/Cu from Cu/+ has been found, but a diligent search in this direction would still be well justified. In six F2's of different crosses there was a consistent although slight deficiency of Cu phenotype, significant for the totals (414+:1089Cu. X^2=5.05, p=0.05- -0.02). The chi square for heterogenecity is not significant (6.59, p = 0.2- 0.1). Interactions with other seedling characters gave no trouble except for c and e. Among the Cu segregants it is very difficult to distinguish segregation for either gene; but very useful linkage information can still be gathered from the segregation among Cu^+ segregants.
The significant indications of linkage between Cu and d in the following data leave little doubt that Cu must abide in the crowded accomodations of chromosome 2. The mean of the two estimates of the d-Cu distance is 37 units, placing Cu beyond Wo, presumably close to Me.
Contingency
tester + + + t Cu + Cu t chi square co.
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a 52 20 172 42 1.66
a 25 5 48 19 1.49
ah 42 11 101 40 0.79
sl 45 19 99 32 0.37
c 58 14 -- -- 0.91
d 41 31 160 54 7.13 39.0 +- 2.6
d 71 67 311 101 57.13 35.5 +- 2.5
dl 37 16 99 42 0.01
e 21 9 54 13 1.25
H 54 10 98 33 1.76
l\1 45 27 157 57 2.53
La 4 8 18 45 '0.01
rv 43 21 90 41 0.37
Xa 23 34 42 82 4.60
yv 38 15 111 30 0.38