The Evolution of Genome Size - Tapa dura

Genes consist of DNA, and their main function is to code for proteins. Therefore one might expect that the amount of DNA per cell would depend mainly on the number of different proteins an organism makes during its life: highly complex organisms with lots of different genes should have much more DNA than simple ones. But in eukaryotes measurements of the amount of DNA per haploid nucleus (an organism's 'genome size' or 'C-value') show no such simple pattern. The fact that some very simple unicellular organisms have huge amounts of DNA per genome, whereas some highly complex multicellular ones have many times less therefore poses a fundamental biological problem known as the 'C-value paradox'. Do the massive amounts of 'extra' DNA in organisms like some salamanders and lilies that have exceptionally large genomes have some function? If so what? Or is the extra DNA merely useless junk or a 'selfish' parasite ('selfish DNA') of the cells replication machinery? This book discusses both the evolutionary causes and the molecular mechanisms of changes in genome size. It emphasises the universal positive correlation between genome size and cell volume, and discusses both natural and experimentally induced changes in genome size.