ISSN:
1573-6849
Keywords:
chromosome banding
;
Coleoptera
;
heterochromatin
;
in situ nick translation
;
mealworm beetle
;
satellite DNA
;
Tenebrio obscurus
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Satellite DNA from the mealworm beetle,Tenebrio obscurus, is composed of 344 bp long monomers of high AT content (68%), and represents 15% of the total DNA.In situ hybridization reveals the positions of the satellite on the pericentromeric heterochromatin of allT. obscurus chromosomes. To compare restriction enzyme (RE) effects with those on naked DNA, fixed chromosomes were digested with REs having recognition sites in most of the satellite monomers, and also with enzymes having target sites present only partially, or very rarely in the satellite units. All enzymes produce similar C-like banding patterns showing heterochromatin resistance to digestion regardless of the enzyme used.In situ nick translation suggests the inability of REs to cleave satellite DNA rather than the inefficient extraction of DNA fragments. DNA in heterochromatin was only extensively digested when the chromosomes were preincubated with proteinase K, indicating that accessibility of REs to DNA is increased by the removal of chromosomal proteins. This is in contrast to recently obtained results inTenebrio molitor, where cleavage of satellite DNA is equally efficient in both fixed chromosomes and in naked DNA. The satellite DNAs of the two congeneric species differ in their AT content, and their primary and higher order structure, which could influence both heterochromatin structure and the accessibility of REs to satellite DNA.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01553322
