DNA REASSOCIATION KINETICS OF FOUR CONIFERS

Abstract

The DNA genome size of four conifers was determined cytophotometrically and the diploid amounts of DNA per cell of Picea glauca (Moench)Voss, Pinus banksiana Lamb., Pinus lambertiana Dougl., and Pinus resinosa Ait. were 19.3, 29.8, 87.7 and 43.1 pg., respectively. These DNA values yield rRNA gene numbers considerably lower than previously published (Hotta and Miksche, 1974). The DNA was further characterized by studying the kinetics of reassociation. The results indicated that in all four conifers there are four repeated nucleotide sequence fractions and one unique fraction. The genome size as determined by reassociation of the single copy DNA approximated the genome size determined by cytophotometry for Picea glauca and Pinus banksiana. Pinus lambertiana and Pinus resinosa appeared to have a genome size, as determined by cytophotometry, larger than the genome sizes determined by reassociation, indicating possible ploidy of their respective genomes.