Ring chromosome

Representative karyotype from a well differentiated transitional cell carcinoma of the bladder. The chromosome indicated by "mar" represents unidentified marker, "r" represents ring chromosome. Arrowheads indicate breakpoints. Also evident are monosomy 9, 18, and X and trisomy 7.

A ring chromosome is an aberrant chromosome whose ends have fused together to form a ring. Ring chromosomes were first discovered by Lilian Vaughan Morgan in 1926.[1] A ring chromosome is denoted by the symbol r in human genetics and R in Drosophila genetics. Ring chromosomes may form in cells following genetic damage by mutagens like radiation, but they may also arise spontaneously during development.

  1. ^ Morgan, LV (Mar 1926). "Correlation between Shape and Behavior of a Chromosome". Proceedings of the National Academy of Sciences of the United States of America. 12 (3): 180–1. doi:10.1073/pnas.12.3.180. PMC 1084483. PMID 16576974.