Uq activation: recovered germinal events

--Yong-Bao Pan and Peter A. Peterson

An additional set of germinally activated Uq elements has been isolated since our first report (MNL 62:5). These newly-arisen Uq's arose either as single or as two separate spotted kernels on a colorless progeny ear upon crossing a-ruq/a-ruq, sectored (or few-spot or colorless sibs) (for terminology see Genetics 119:457) with an a-ruq tester. They all elicit a heritable unique and distinguishable spotting pattern when interacting with the a-ruq reporter allele (Table).

Table. Properties of germinally activated Uq elements.

The Uq nature of this exceptional activity has been tested using two approaches. First, in order to prove a-ruq was the only reporter allele in the original mutant, twelve colorless sibs, derived from the confirmation ear (the spotted mutant x a sh2 (no Uq)), were crossed with a standard Uq element. The results of these crosses confirm that a-ruq was the only allele present. Secondly, an a sh2/a sh2 Uq/Uq (or +) line was constructed and this was followed by crossing this line to the standard a-ruq, a-m1, a-m(r)h, and a-mdt reporter alleles. A spotting phenotype was produced only from the interaction between the a-ruq reporter allele and the element in the a sh2 line thereby confirming the Uq nature of the original mutant. In addition, the ability of these new germinally activated Uq elements to transactivate a c-ruq reporter allele was also tested (Table) and this gave variable results.

Allelism tests between a standard Uq and four germinally activated Uqs (Uq-870801U, Uq-870621Y, Uq-870829U and Uq-870829Y) are underway.

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