Cytological analyses of 14p+ variant by means of N-banding and combinations of silver staining and chromosome bandings.

An inherited human karyological variant (14p+) has been studied with a number of cytochemical techniques. The short arm of this variant chromosome 14 is nearly as long as the long arm, giving the chromosome a submetacentric to metacentric appearance. In conventionally Giemsa-stained preparations, maximum of three secondary constrictions can be observed the marker arm. The secondary constrictions are silver-positive in Ag-NOR preparations. However, the entire arm stains deeply in N-banded preparations. The 14p+ arm is also Q-negative, C-negative, G-negative, and R-positive with an almost homogeneous texture. The difference between N-banding and silver staining is interpreted as the result of gene activities of the ribosomal cistrons.