here it is shown , using in situ hybridisation to the alpha-1 antitrypsin genes , which map at a unique site , that while there is a tendency for duplicated chromosomes to cluster , this does not involve the complete fusion of replicated chromatids found in fully polytene chromosomes , and in a substantial proportion of homologues the sites on the chromosome arms corresponding to these genes are widely separated .
C0008633
chromosomes
C0449721
chromosome arms