Strong bristle phenotype.

strong allele Associated with simultaneous mutation to club wing, clw, a defect in wing expansion with low penetrance. sn⁴⁹ is unstable, producing an array of derivatives that are in turn stable or unstable. and the expression of clw differs among them. It mutates to sn⁺ and back at a rate of approximately 10^-3; a rare moderate singed derivative exhibits an approximately ten-fold elevation in mutation frequency, mutating either back to the strong allele or to an unstable normal allele; a single extreme singed derivative of a normal derivative of the moderate allele produces strong-singed and non-singed derivatives, which can in turn revert to the extreme allele and in the case of the strong derivative to non singed (Yurchenko, Zakharov and Golubovsky, 1984). unstable; also clw mutant