[Mobile genetic elements and quantitative characters in Drosophila: facts and hypotheses]

Abstract

This review is dedicated to the comparison of the facts obtained and the proposed hypotheses, to the critical analysis of the situation arisen, and to the estimation of key propositions of the concept developed. The main point is that mobile genetic elements (MGEs) participate directly in expression, variability, selection and evolution of different quantitative characters. Genetic and selection data are considered, and hypotheses of random fixation, marker effect and direct participation of MGE patterns in expression and selection of quantitative characters are discussed. The consequences of temperature treatment are considered and hypotheses of masked selection and temperature induction of transpositions are discussed. The marker effects are shown to be non-sufficient to explain the properties of quantitative character radius incompletus system. The MGE patterns are important components of genetical system of determination of a quantitative character. MGEs modify, enhance the expression of neighbouring polygenes. Temperature effects could be explained by the influence of stress temperature treatment through the system of heat shock response on the capacity of MGEs to transcribe and transpose. The system of diversed MGE patterns in drosophila chromosomes could be believed to be universal genomic system of "soft" modification of the polygenic control of any limiting quantitative characters.