MARKER DOTS ARE EXPELLED BY ATTENUATION IN HETEROCHROMATIN OF A CHROMATID
H. K. GOSWAMI GOSWAMI *
Department of Genetics, Barkatullah University, Bhopal-462 026, India.
S. I. CHANG *
Department of Genetics, Barkatullah University, Bhopal-462 026, India.
*Author to whom correspondence should be addressed.
Abstract
Marker dots (1.0-2.5 µ) have been known to emanate from some chromosomes indicating precursors/indicators to chromosomal mutagenesis among certain persons including cancer patients. These are principally euchromatic (GC rich) as evidenced by various banding schedules. This study apart of chromosomal survey has been based on reinvestigation of 110 individuals (out of 605) yielding more than 15000 metaphases for analysis. Marker dots' preferred loci of origin are telomeres and the fundamental mechanism may involve the release of transposable euchromatin by heterochromatic attenuation. Probably this is a precursory mechanism for progressive heterochromatinisation.
Keywords: Heterochromatic attenuation, chromosomal mutagenesis indicator, Marker Dots