Rick, C. M.
In TGC 9:42-43 I reported some data that suggested a possible linkage between ht and d\1 on chromosome 2. Since all the families segregating for the two genes did not consistently show dissociation, it was stated that confirmation of this linkage and tests with other markers would be desirable. In the meanwhile new tests have been completed with m and some additional ones have been made with d\1, as tabulated below.
Adjusted
contingency
Tester + + t ht + ht t Chi-square
d F2-R 110 33 21 6 0.023
d F2-R 88 25 27 8 0.020
m F2-R 66 11 14 4 0.219
m F2-R 110 33 21 6 0.023
Wo F2-R 28 44 3 7 <0.1
All of these new tests show random association between ht and the chromosome 2
markers. Since m and Wo lie on either side of d\1, the significant values
reported in TGC 9 could not have reflected linkage of ht with d\1. They
probably resulted instead from misclassification of multiple recessives. Each
d\1-ht family reported in TGC 9 also segregated for c, and the c-d\1-ht
interaction is of such a nature that d\1-ht compounds could have been
misclassified. This problem did not complicate identification in the two
families of d\1-ht reported above, for c was not segregating in the second and
the first (segregating) was grown to maturity in the field,, where and ht coad
be identified unequivocally. It is therefore evident that no linkage has yet
been found for ht.