Satellite III DNA: Regions of extreme endonuclease resistance and interindividual polymorphism in the Mb size range

Abstract

Southern analysis of within-gel digested and restricted human cells has revealed very large Satellite III restriction fragments which show clear inter-individual length polymorphism. The Mb and sub-Mb length of these fragments indicate that they arise from regions of heterochromatin which contain homogeneous Satellite III sequences of peculiar resistance to common endonucleases. Based on sequence alone, such regions would be little digested by endonuclease digestion of chromatin in metaphase, regardless of its method of preparation. Polymorphic regions such as these might be expected to stain as part of the C-banding seen in endonuclease treated metaphase chromosomes, and may in part account for inter-individual C-band heteromorphisms.

Chromosomal diversification in the gekkonid Tarentola mauritanica (Reptilia, Gekkonidae)

“…2e, g). This might depend either on its peculiar molecular conformation limiting the access to the cleavage target sequences (LopezFernandez etal, 1991), or, alternatively, to the occurrence of satellite-DNA sequences resembling those found in man, which display a peculiar resistance to common endonucleases (Flower & Burgoyne, 1992).…”