A concept developed to explain the observation that over 90% of the genomes of most eukaryotes are made up of noncoding DNAs. According to Cavalier-Smith, this “secondary” DNA functions as a skeleton that increases the volume of the nucleus and so gives the coding genes more space in which to operate. The skeletal DNA determines the size of the nucleus, and this in turn controls cell volume, which is optimized by selection. See Chronology, 1999, Beaton and Cavalier-Smith; cryptomonads, C value paradox, junk DNA, selfish DNA.
Subjects: Genetics and Genomics.