an electronmicroscopical mapping of a number of regions of the polytene chromosomes of ch . thummi salivary glands ( 3rd chromosome , right arm of the 1st chromosome , centromere regions , puffs 1-a2e , 1-a3ij , iii-a5c and others ) was done by the method of oriented ultrastructural sections of the unsquashed polytene chromosomes .
C0008633
chromosome
C0007709
centromere