MARKER DOT IS INDICATOR OF CHROMOSOMAL MUTAGENESIS

Marker dots (MD) have been observed as extrachromatin bodies ranging from 1 to 2.5u in diam. in those cells which possessed some or the other chromosomal aberration. These dots have been observed to detach from chromosomes at any place and are also partly C-positive. G-banded metaphases have shown them to be present in the vicinity of chromosomes. Their presence in lymphocytes of patients exhibiting various tumours, recurrent abortions and some syndromes may be suggestive that these marker dots may be indicative of chromosomal mutagenesis.