Browsing by Author "G.S. Garg"

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Constitutive heterochromatin and karyotype variation in Indian pygmy mouse, Mus dunni
(1975) T. Sharma; G.S. Garg
The Indian pygmy mouse, Mus dunni, exhibits great variation in the number of chromosome arms while its diploid number of chromosomes remains constant. The variation seems to be due to addition or deletion of C-band positive constitutive heterochromatin in the short arms of autosomes. © 1975, Cambridge University Press. All rights reserved.
Giemsa banding pattern of muntjac chromosomes
(1973) T. Sharma; G.S. Garg
The Giemsa banding patterns of Indian muntjac chromosomes stained after denaturation and renaturation of DNA were similar to the fluorescent staining patterns reported by others using quinacrine mustard.
Restrictive localization of centromeric heterochromatin (C-bands) in Presbytis e. entellus (Dufresne) as compared to Macaca mulatta (Zimmerman)
(1974) T. Sharma; G.S. Garg
C-bands are observed in the centromeric regions of only three pairs of autosomes and the distal portion of the small acrocentric Y in a total complement of 44 chromosomes of a male Presbytis e. entellus. Simultaneously treated slides of a Rhesus monkey, however, have C-bands in all the 42 chromosomes. The lack of C-bands may be due to (1) absence of highly repetitive DNA in the centromeric region of certain chromosomes or (2) presence of minute quantity of such DNA which is imperceptible or (3) different types of centromeric heterochromatin with a varying degree of repetition of DNA sequences all of which do not react in similar manner to various techniques employed at present. It is hypothesized that the centromeric heterochromatin rich in satellite DNA helps in withstanding the force of excessive coiling of chromosomes at the centromere to facilitate the functioning of the genes for microtubular protein during cell division when other genes are rendered inactive due to compactness of chromosomes. © 1974.