LINKAGE STUDIES INTRIBOLIUM CONFUSUMDUVAL. II. THE MAP POSITION OF THREE HOMEOTIC MUTANTS.

Abstract

In the tenebrionid flour beetle T. confusum the mutant labiopedia (lp) modifies the labial palps into legs; pointed abdominal segments (pas) modifies apparent abdominal sternites 2-5 to resemble the first apparent abdominal sternite, and the males, apparently because of mechanical reasons, are sterile; alate prothorax (apt) produces a pair of elytra-like appendages in the prothorax. The relative position of these 3 homeotic mutants on the X chromosome in relation to Striped (St) and evespot (es) is probably St[long dash]es" - apt -pas - lp, with recombination values between St - es = 37.6; es - lp = 45.2; apt - lp = 4.1 and pas - lp = 3.4. (The relative position of apt and pas is assumed to be in the order given). Current information on homeotic mutants affecting appendages of the head and producing wings on the prothorax in the Orthoptera, Diptera and Coleoptera is summarized, and the usefulness of homeotic mutants discussed. The genetics and phenotypic effect of certain mutants in T. castaneum and T. confusum are compared. Alate prothorax and prothoraxless have autosomal inheritance in T. castaneum while in T. confusum similar mutants (alate prothorax and prothoraxless-like are sex-linked). These may represent homologous genes whose genetic behavior is different because of the karyotype history of the 2 species.