The highest gene concentrations in the human genome are in telomeric bands of metaphase chromosomes

摘要: Abstract Chromosome in situ suppression hybridization has been carried out on human metaphase chromosomes to localize the G+C-richest DNA fraction (which only represents 3.5% of genome), as isolated by preparative equilibrium centrifugation Cs2SO4/3,6-bis(acetatomercurimethyl)-1,4-dioxane density gradient. This essentially corresponds isochore family H3. The rationale for carrying this experiment is that has, far, highest gene concentration, concentration CpG islands, transcriptional and recombinational activity, a distinct chromatin structure. results obtained show H3 localized two coincident sets bands chromosomes: telomeric chromomycin A3-positive 4',6-diamidino-2-phenylindole-negative bands. result first step toward complete compositional map karyotype. Because G+C gradient across families paralleled gradient, such structural, functional, evolutionary relevance.