> Mustafa
The book you should read is a compilation by Tom Cavalier-Smith
called "The Evolution of Genome Size", published sometime in the
mid-eighties.
The majority of multicellular eukaryotic genomic DNA is not
made up of coding sequence which has obvious phenotypic effect
on the organism (at least on structures above the level of the
cell). It is largely made up of repetitive DNA. That is either
repeated short sequences (5 or less bases) or repeated longer
sequences, like Alu elements. Coding sequence for many animals
and plants may make up as little as 5% or less of the total
genome size.
The various theories explaining why genomes like these have
evolved are outlined in Cavalier-Smith's book.
Andrew Roger
Dept. of Biochem
Dalhousie University
aroger at ac.dal.ca
