2C DNA Values Research Articles

Analysis of cellular DNA distributions. I. G2/G1 channel ratios.

In the influencent-flow cytophotometric measurement of cellular DNA content the DNA distributions usually have two peaks. The second peak, which corresponds to the 4C DNA content of G2 and M cells, is often positioned at lower values of DNA content than twice that of the 2C DNA peak which contains G1 cells. Computerized numerical analyses were performed on artificial DNA distributions in which the proportion of S-phase cells was varied. It was demonstrated that the contribution of late S-phase cells to the 4C DNA peak in the histogram shifts the second peak to a position below twice the 2C DNA value. Also, increasing the coefficient of variation of the DNA measurement shifts the second peak position to lower values. A group of 33 DNA distribution histograms we found to have an average G2/G1 peak position ratio of 1.90, in keeping with typical values obtained from the numerical analysis of the artificial populations.

NUCLEAR DNA CONTENT IN POPULATIONS OF PINUS RIGIDA

Five populations of Pinus rigida growing in contrasting ecological situations ranging from North Carolina (35°53'N latitude) to Quebec (45°06'N latitude) showed no significant variation in amounts of nuclear DNA with respect to germinating seedlings. Nuclear volume of dormant nuclei also showed no significant variation between and within populations, a finding that is consistent with the concept that the basic 2C DNA value of Pinus rigida is uniform under all habitats. This finding is in contrast to numerous reports for other coniferous species.

Nuclear DNA Content in Populations of Pinus Rigida

Five populations of Pinus rigida growing in contrasting ecological situations ranging from North Carolina (35°53'N latitude) to Quebec (45°06'N latitude) showed no significant variation in amounts of nuclear DNA with respect to germinating seedlings. Nuclear volume of dormant nuclei also showed no significant variation between and within populations, a finding that is consistent with the concept that the basic 2C DNA value of Pinus rigida is uniform under all habitats. This finding is in contrast to numerous reports for other coniferous species.