REVIEW PAPER
Structure and functions of lampbrush chromosomes

Lampbrush Chromosomes (LBCs) are present in the oocytes of birds, lower vertebrata and invertebrates during

the prolonged prophase of the first meiotic division. Their name stems from their similarity to bottle brushes.

Lampbrush chromosome of the early prophase is a bivalent, made up of two conjugating homologues. The axis

of each homologous chromosome is formed by sister chromatids that are differentiated into regions of transcriptionally

active and inactive chromatin. Transcription activity of LBCs is observed as a mantle of symmetrically

distributed side loops along the chromosome axis. Changes in transcriptional activity are reflected in changes in

their morphology. Transcriptional activity of LBCs is directly connected with physiological processes of the body

and shows in the morphological structure of the chromosomes. The use of cytogenetic techniques and in situ

hybridization have made it possible to identify unique and repeating sequences as well as DNA replication proteins

in LBCs. Particularly, interesting prospects are offered by the possibility of using LBCs in studies of transcriptional

activity, cytogenetic investigations of karyotype evolution and genome mapping.