ISSN:
1432-1432
Keywords:
Brine shrimp
;
AluI DNA
;
Nucleotide variation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary It has been suggested that DNA bending could play a role in the regulation of gene expression, chromosome segregation, specific recombination and/or DNA packaging. We have previously demonstrated that an Alul DNA family of repeats is the major component of constitutive heterochromatin in the brine shrimp A. franciscana. By the analysis of cloned oligomeric (monomer to hexamer) heterochromatic fragments we verified that the repetitive AluI DNA shows a stable curvature that determines a solenoidal geometry to the double helix. This particular structure could be of relevant importance in conferring the characteristic heterochromatic condensation. In this paper we evaluate how the point mutations that occurred during the evolution of the Alul sequence of A. franciscana could influence the sequence-dependent tridimensional conformation. The obtained data underline that, in spite of the high sequence mutation frequency (10%) of the repetitive DNA, the general structure of the heterochromatic DNA is not greatly influenced, but rather there is a substantial variation of the copy number of the repetitive AluI fragment. This variation could be responsible for the hypothetical function of the constitutive heterochromatin.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00160209
Permalink
