Cytochemical evaluation of C-heterochromatic-DNA in metaphase chromosomes.
A method is proposed to evaluate the amount of DNA resistant to the C-banding pretreatments (C-heterochromatic-DNA) in metaphase chromosomes. Measurements were performed by microfluorometry on propidium iodide stained metaphases of man, gorilla and mouse; in these species, C-heterochromatin exhibits significant differences of both base composition and distribution along the chromosomes. The amount of C-heterochromatic-DNA was found to be about 16%, 28% and 58% of the total DNA content (genome size) in man, gorilla and mouse, respectively. The areas of C-bands after Giemsa staining were also assessed by microdensitometry, and corresponded to about 8%, 15% and 14% of the total karyotype area of man, gorilla and mouse respectively. No direct relation thus exists between C-band areas and the amount of DNA resistant to the C-banding pretreatments. In man and gorilla, the amount of C-heterochromatic-DNA accounts for the differences observed in genome size.
Pellicciari
C
C
Dipartimento di Biologia Animale, CNR, Pavia, Italy.
Ronchetti
E
E
Tori
R
R
Formenti
D
D
Manfredi Romanini
M G
MG
D000818:Animals; D002871:Chromosome Banding; D005434:Flow Cytometry; D006071:Gorilla gorilla / Q000235:genetics*; D006570:Heterochromatin / Q000032:analysis*; D006651:Histocytochemistry / Q000379:methods*; D006801:Humans; D008214:Lymphocytes / Q000032:analysis / Q000166:cytology*; D008677:Metaphase; D051379:Mice; D011419:Propidium; D013194:Staining and Labeling
D006570:Heterochromatin; D011419:Propidium