c2-m826021-An autonomously controlled allele at the c2 locus

c2-m826021 is an unstable c2-m allele that originated in an isolation plot (MNL 57:2) containing genotypes with En. The general pattern of this allele is very late in timing, though occasional early sectors appear. The frequency is largely a 6aa-type (very late-near single cell, but frequent-Reddy and Peterson, MGG 194:124), though this medium high frequency is not strictly heritable.

In tests of specific control, it has been confirmed that the control of mutability is autonomous. In 31 test crosses, the mutability cosegregated with the c2 locus. The frequency of colorless types ranged from .4% to 2. 1% among eight of the 31 crosses.

Two examples of this cross:
 
  Colored spotting cl Total
84 1001-1/0707-6 255 273 4 532
84 1002-1/0709-7 263 236 0 499

This demonstrates the autonomous control of the mutability. Though En is strongly implicated, additional tests are needed for confirmation. The alternative of numerous En to accommodate the incidence of colorless segregants would require from 4 to 5 En, which is not applicable in this experiment.

Ulla Niesbach-Klosgen and Peter A. Peterson

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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