An Interchange Heterozygote in Vicia faba

Abstract

DURING cytological investigations into the action of ethyleneimines upon root-tip cells of Vicia faba, variety Sutton's Seville Long Pod, one treated seedling was found in which all dividing cells possessed a chromosome complement differing from that of the normal seedlings. Observations and measurements of the chromosome complement, carried out on eight metaphase cells from normal seedlings, showed that it was possible to recognize, apart from pairs 3 and 4, each of the six pairs of homologues by the length of their long arms. Pairs 3 and 4 could be distinguished from one another by the size of their short arms. The six pairs of homologous chromosomes of the normal complement are shown diagrammatically in Fig. 1a, together with the complement of the treated seedling in Fig. 1b.