A Supernumerary Chromosome in Locusta

Abstract

THE chromosomes of Locusta migratoria normally comprise eleven pairs of autosomes ranging from 1.2µ to 5.3µ, with two X-chromosomes in the female and one X in the male¹. In 1934, however, Itoh² described locusts in a Japanese population which contained an additional chromosome, present in variable numbers and supernumerary to the normal complement. Recently, we have found such supernumerary chromosomes in a stock used in this Department. Each extra chromosome has a sub-terminal centromere and is slightly larger than any member of the three smaller autosome pairs. In these and other respects the supernumeraries appear to be similar to those found by Itoh in Japan. Dr. C. E. Ford and Mr. J. L. Hamerton, of the Radiobiological Research Unit, Harwell, and Mr. C. G. Elliott, of the Botany School, Cambridge, have kindly informed us that they too find supernumerary chromosomes in locust stocks related to our own.