[Genetic analysis of a polygenic system of a quantitative character after negative and positive selection. I. General characteristics of the polygenic system].

Genetic analysis of phenotypic expression of the quantitative character controlled by an oligogenic mutation radius incompletus (ri) and a polygenic system in Drosophila melanogaster was carried out. Flies from the control line riC and two contrasting selection lines, riSR (positive selection) and riSN (negative selection) were crossed to the wild-type line riN. Proximal and distal segments of the longitudinal wing vein were measured in F2 ri/ri homozygotes. RiC and riN lines were shown to carry sets of polygenes with equivalent phenotypic contribution while selection lines (riSP and riSN) had an excess of polygenes of positive and negative effect, respectively. Striking similarity in some features of the polygenic system and localization of mobile genetic elements in the chromosomes of the lines was demonstrated.