Cytochrome c oxidase subunit 1 analysis of Xiphinema diversicaudatum, X. pachtaicum, X. simile and X. vuittenezi (Nematoda, Dorylaimida)

Genetic analyses using sequences of partial cytochrome c oxidase subunit 1 (cox1) gene of mitochondrial DNA were conducted to determine the extent of genetic variation within and among Xiphinema diversicaudatum, X. pachtaicum, X. simile and X. vuittenezi populations. Pairwise distance among the four species was 22.5 to 31.2%. Four different sequence variants of cox1 were determined among six populations of X. diversicaudatum and three variants among three populations of X. simile. Nucleotide variation was detected at 18 of 414 bp (1.9 to 2.7%) in X. diversicaudatum and 4 of 435 bp (0.2 to 0.9%) in X. simile. All changes were at silent sites. No nucleotide variation was detected within three populations of X. pachtaicum and within three populations of X. vuittenezi.