Open AccessNucleotide sequence organization in the very small genome of a tetraodontid fish, Arothron diadematus
Author(s) -
PIZON Véronique,
Cuny Gérard,
BERNARDI Giorgio
Publication year - 1984
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1984.tb08062.x
Subject(s) - dna , genome , biology , microbiology and biotechnology , dna sequencing , nucleotide , genomic dna , repeated sequence , nucleic acid sequence , satellite dna , base pair , gene , genetics
We have investigated the sequence organization of the very small genome (DNA content/haploid cell c = 0.4–0.5 pg) of a tetraodontid fish, Arothron diadematus , by using two main experimental approaches. The first one, renaturation kinetics, showed that slowly reassociating, intermediate, fast and foldback sequences represented 87%, 7%, 5% and 1%, respectively, of A. diadematus DNA, which is, so far, the vertebrate DNA lowest in repeated sequences. The second approach, centrifugation in Cs 2 SO 4 /BAMD density gradients [BAMD = bis(acetate‐mercurimethyl)dioxane], showed that A. diadematus DNA can be resolved into several components, characterized by buoyant densities of 1.700, 1.704 5 , 1.708, 1.712 and 1.723 g/cm 3 , and representing 15%, 73%, 4%, 4% and 2.5%, respectively, of total DNA. The last component comprised a satellite DNA and ribosomal DNA. A family of interspersed repeats, possibly related to the Alu I family of warm‐blooded vertebrates, showed an extremely specific genomic distribution, being present in only the 1.708 g/cm 3 component, which it matched in base composition.