Somatic synapsis in chironomus, with special reference to the individuality of the chromosomes



The nuclear band of the cells of the salivary glands of Chironomus larvae regularly consists of four segments or chromosomes. Each of these may be recognized by its characteristic distribution of chromatin discs of various sizes. When nucleolar elements are present they have a definite location in relation to the chromation discs of a certain chromosome. The diploid number of chromosomes is eight; therefore, the four segments in the cells of the salivary glands represent four pairs of homologous chromosomes in somatic synapsis which here is not a simple approximation but an accurate pairing part by part of the homologous chromosomes.