LINKAGE STUDIES IN TRIBOLIUM CASTANEUM. XI. THE MAP POSITION OF CHARCOAL, A PSEUDOALLELE OF BLACK

Abstract

Charcoal, (Chr), an autosomal dominant with recessive lethal effects is located in linkage group III in Tribolium castaneum (Herbst). Its map position has been determined in respect to aureate (au), light ocular diaphragm (lod) and black (b). The distances between the various genes vary, depending on the sex of the cross. The Chr ++/+ lod au ♂ × +lod au/+lod au ♀ crosses give the following recombination values: au-lod = 22.19 ±.42%, Chr-lod = 20.03 ±.40% and Chr-au = 41.28 ±.49%. The reciprocal crosses give au-lod 28.08 ±.45%, Chr-lod = 17.67 ±.38% and Chr-au = 44.11 ±.50%. For the larger distances encompassed by the Chr-au region the recombination values in the two sexes were not significantly different. For the shorter distances the recombination values were significantly higher in the males than in the females in the au-lod region. They were not found to be significantly different in the Chr-lod region probably because of difficulty in identifying lod and non-lod beetles in the presence of Chr. Tests of allelism indicate that Chr and black b are pseudoalleles which recombine at a different rate in the two sexes. Chr +/+b ♂ × +b/+b ♀ gave 0.07% recombinants, while the reciprocal cross gave 0.014% recombinants, a significant difference. The data suggest that the order of the genes in this linkage group is Chr - b - lod - au.