Comparison of active transcription regions of lampbrush chromosomes with the mitotic chromosome G pattern in the European domestic goose Anser anser

Abstract. The most complete information on the karyotype is acquired through the observation of chromosomes obtained from dividing cells. A high number of chromosomes and the presence of microchromosomes in the bird karyotype have made cytogeneticists look for other sources of information on chromosomes. Information sources of great value for the bird karyotype analysis are meiotic chromosomes, specifically represented by lampbrush chromosomes. Lampbrush chromosomes (LBCs) found in developing oocytes of birds are perceived as a new model in cytogenetics which is especially important in the analysis of bird chromosomes. A typical LBC analysis enables one to assess transcription activity on the basis of LBC morphology (inactive chromomeres and side loops). A comparison of lampbrush chromosome transcription activity and the GTG pattern of the corresponding mitotic chromosomes have proven that active transcription regions with side loops correspond to G-positive bands on mitotic chromosomes.