A COMBINED METHOD FOR MAPPING POLYTHENE CHROMOSOMES ON THE EXAMPLE OF THE FOURTH MICROCHROMOSOME OF DROSOPHILA...

Genetic activity of interphase chromosomes is associated with their structural organization, but the mechanism of these relations is still unclear. Classic polythene chromosomes of dipteran insects are a convenient model for such investigations. Despite intensive study of polythene chromosomes of Drosophila melanogaster is carried out, an exact conformity of bands and interbands to the molecular map of the genome remains unknown in most cases. For addressing this issue, the genetic map and molecular characteristics of chromatin have been compared with the banding pattern of the fourth chromosome, which is the smallest chromosome in the D. melanogaster genome and is different in many ways from other chromosomes. This is a unique chromatin domain of D. melanogaster, which is characterized by specific proteins, including HP1, POF and EGG. Matching of cytological and physical maps of the fourth chromosome has been carried out by FISH. Genomic coordinates of bands and interbands have been determined. This result makes it possible to investigate the regulation of gene activity of the fourth chromosome in the context of molecular characteristics of cytological structures in which these genes are located.