Lampbrush chromosomes are typically observed in which type of cells?

• A. Muscle cells
• B. Oocytes
• C. Sperm cells
• D. Glial cells

Answer: (B)

Lampbrush chromosomes are a feature of oocytes during the prolonged prophase I stage of meiosis, specifically diplotene, when chromatin extends into long lateral loops from a central axis. Those loops are sites of intense transcription, building up the maternal RNA and ribosomal components needed for early embryonic development. The many active transcription units give the chromosomes a bright, brush-like appearance under a light microscope, hence the name. This pattern isn’t seen in most somatic cells or in mature sperm cells, where chromatin is highly condensed and transcription is largely off. So, lampbrush chromosomes reflect a specialized transcriptionally active state in growing oocytes, not in muscle, glial, or sperm cells.