GENETICS AND EXPRESSION OF PATCHY, A MOSAIC MUTANT OF THE GERMAN-COCKROACH (DICTYOPTERA, BLATTELLIDAE)

The patchy (Pch) mutant of the German cockroach is characterized by ge nerally large areas of dark and light pigment on the body surface of n ymphs. Pch is inherited as a dominant trait, lethal as a homozygote, w ith full penetrance and strong expression when the stock is homozygous for yellow body (y/y). Expression and penetrance varied in crosses to wild type and to markers for 8 of the 11 autosomal linkage groups and , in most crosses, were reduced compared with Pch in y/y homozygotes. Analysis of the degree of expression revealed differences between regi ons of the abdomen and thorax of late instars. Patterns were usually d ifferent between left and right sides and discontinuous across the med ian line of the body. Differences tended to be greater across median o r dorsoventral borders than across segmental borders. In one cockroach , Pch was expressed as a segmental mosaic.