The use of high resolution microscope photometry in the discrimination of chromosome bands.

High resolution microscope photometry was used to discriminate between regions of differing density along the length of a banded metaphase chromosome. It has been demonstrated that photometry can be performed on such material to give a higher level of effective resolution than has hitherto been obtained. Using conventional visible light microscope photometry it is possible to obtain useful comparative densitometric information from measurements performed at a point separation equivalent to 0.05 micrometer in the object plane. The practical details of the equipment employed and the theoretical basis of the study are discussed.