For 50 years now, one of the enigmas of molecular evolution has been the C-value paradox, which refers to the often massive, counterintuitive and seemingly arbitrary differences in genome size observed among eukaryotic organisms. For example, the genome of the fruitfly Drosophila melanogaster is 180 megabases (Mb), whereas that of the European brown grasshopper Podisma pedestris is 18,000 Mb. The difference in genome size of a factor of 100 is difficult to explain in view of the apparently similar levels of evolutionary, developmental and behavioural complexity of these organisms.
Hartl, D LengResearch Support, U.S. Gov't, P.H.S.ReviewEngland2001/03/20 10:00Nat Rev Genet. 2000 Nov;1(2):145-9.