Intraspecific variation in the structural organization and redundancy of chloroplast ribosomal DNA cistrons in Euglena gracilis.

Chloroplast DNAs from six different laboratory collections of Euglena gracilis "strain Z" and var. bacillaris were analyzed with restriction endonucleases EcoRI and Bam HI. The most variable portion of the organelle genome is the region containing the ribosomal cistrons. Intraspecific differences occur in both ribosomal DNA cistron number (one or three) and structural organization among those strains designated as "strain Z" and bacillaris. One culture previously designated as "Z" is most likely bacillaris.