INFLUENCE OF DENSITY OF CROP ON DEGREE OF POLYTENY OF GIANT CHROMOSOMES OF INBRED LINES AND HYBRIDS OF Drosophila melanogaster

摘要

The influence of the density of a culture and the genotype on the degree of polyteny of giant chromosomes in Drosophila melanogaster are investigated. A reliable depression of the function of endoreduplication of polytene chromosomes as the density of the culture increases is found. An essential dependence of the degree of polyteny of giant chromosomes on genotype is demonstrated. A correlation between the degree of polyteny of giant chromosomes and a number of adaptively important features is established. A well-defined parallelism between amplification of the manifestation of the effect of heterosis in a number of quantitative features and dominance of hybrids over inbred lines with respect to the degree of polyteny of giant chromosomes under conditions of overpopulation is discovered. Sex differences and a maternal effect in the inheritance of the degree of polyteny of giant chromosomes in Drosophila are demonstrated.