Polymorphism and linkage analysis of the prothoracicotropic hormone gene in the silkmoth,Bombyx mori

Abstract

SummaryWe looked for polymorphism of the prothoracicotropic hormone gene locus (Ptth) among inbred strains of the silkmoth,Bombyx mori, by invitroDNA amplification (polymerase chain reaction), and found three alleles,PtthA,PtthBandPtthC. ThePtthAallele contained a third intron consisting of 680 bp and a fourth intron of 350 bp.PtthBcontained the same size third intron but a longer fourth intron of 490 bp, while Ptthc had a longer third intron of 1080 bp and a shorter fourth intron of 350 bp. In 29 strains which we examined, 9 strains hadPtthA, 8 strains hadPtthB, and 2 strains had Ptthc. The other 10 strains had heterogeneous genotypes with the same 3 alleles.