A Lampbrush chromosome is a large chromosome that found especially in the oocytes (immature eggs) of amphibians. Lampbrush chromosomes occur during a special meiosis. It is consisted of two long strands that form many brushlike loops along the main axis of the chromosome. The outgrowths make DNA available for transcription during the maturation of the egg.
usually there is a little gene expression at meiosis, so it could not be used to identify the activities of individual genes.Lampbrush chromosomes can solve this problem, it allows the material to be examined.
lampbrush chromosomes are meiotic bivalents,each consisting of 2 pairs of sister chromatids.