Shakina L. Structural and functional organization of polytene chromosomes in Drosophila melanogaster Meig. in relation with heterosis effect, isogenization and the culture density influence

The object of study: structural organization and functional activity of chromosomes in drosophila depending on genotype and culture density. The aim of study: the study of structural and functional chromosomes’ features and manifestation of adaptive traits in D. melanogaster in relation with effect of heterosis, isogenization and culture density. Methods of research: genetic analysis, method of pressed acetoorceinic preparations of polytene chromosomes, cytomorphometric, methods of fitness definition in lines and hybrids F1, mathematical analysis of the received data. Theoretical and practical results, newness: The decrease of polyteny degree (PDC) and puffing activity in drosophila giant chromosomes in inbred lines and F1 hybrids under increased culture crowding and dependence of this effect on a genotype were found for the first time. The correlation of parameters PDC and puffing activity in a number loci with manifestation of adaptive traits was revealed in drosophila. The existence of genetic differences on parameters of ectopic pairing and frequency of asynapsis in the area of ectopic pairing in inbred lines and F1 hybrids was established. It was shown that the process of chromosomes isogenization influenced negatively on the PDC parameter, puffing activity, fitness, egg production and expressivity of the character Bar in drosophila. The data concerning changing of unequal crossing over frequency in the locus Bar and frequency of the dominant lethal mutations under the larval crowding and drosophila chromosome isogenization were received for the first time. The sphere of application: fundamental and applications genetics, selection.