Figure 1
From: Short-term sequence evolution and vertical inheritance of the Naegleria twin-ribozyme group I intron
Distribution of the Nae.S516 introns among Naegleria isolates. NJ phylogenetic tree of the ITS-rDNA based on 287 nucleotide positions and 70 Naegleria isolates. NJ bootstrap values above 50% are shown at the branches. The six clusters of Naegleria isolates (Cluster 1–6) are indicated according to [1,2]. Naegleria isolates known to contain (21 isolates) or lack (49 isolates) the Nae.S516 intron are shown in red or black, respectively. All introns are approximately 1,3 kp in size (corresponding to a twin-ribozyme organization), except N. byersi NG597 which is 375 bp (only NaGIR2). The N. fowleri branch in Cluster 1 represents 21 distinct isolates.