Extranuclear DNA of a Marine Chromophytic Alga : RESTRICTION ENDONUCLEASE ANALYSIS.

Two extranuclear DNA species have been isolated from the marine alga Olisthodiscus luteus. Rapid lysis of cells followed by the immediate addition of CsCl to the lysate was critical to the preservation of these satellite DNA species. Restriction endonuclease analysis demonstrates a molecular weight of 99 x 10(6) for chloroplast DNA and 23 x 10(6) for a second satellite species. The origin of the second satellite is not known. However, this smaller satellite DNA which originates from a nonnuclear, DNAse insensitive cellular component, displays no sequence homology with ctDNA by hybridization experiments. Constancy of restriction endonuclease fragment patterns of chloroplast and second satellite species during all phases of the growth cycle, whether cultures were maintained synchronously or asynchronously, was demonstrated.