The Mitochondrial Genome ofBaylisascaris procyonis
Xie Y, Zhang Z, Niu L, Wang Q, Wang C, Lan J, Deng J, Fu Y, Nie H, Yan N, Yang D, Hao G, Gu X, Wang S, Peng X, Yang G.
Abstract
BACKGROUND:Baylisascarisprocyonis(Nematoda: Ascaridida), an intestinal nematode of raccoons, is emerging as an important helminthic zoonosis due to serious or fatal larval migrans in animals and humans. Despite its significant veterinary and public health impact, the epidemiology, molecular ecology and population genetics of this parasite remain largely unexplored.Mitochondrial(mt) genomes can provide a foundation for investigations in these areas and assist in the diagnosis and control ofB. procyonis. In this study, the first complete mtgenomesequence ofB. procyoniswas determined using a polymerase chain reaction (PCR)-based primer-walking strategy.
METHODOLOGY/PRINCIPAL FINDINGS:The circular mtgenome(14781 bp) ofB. procyoniscontained 12 protein-coding, 22 transfer RNA and 2 ribosomal RNA genes congruent with other chromadorean nematodes. Interestingly, theB. procyonismtDNA featured an extremely long AT-rich region (1375 bp) and a high number of intergenic spacers (17), making it unique compared with other secernentean nematodes characterized to date. Additionally, the entiregenomedisplayed notable levels of AT skew and GC skew. Based on pairwise comparisons and sliding window analysis of mt genes among the available 11 Ascaridida mtDNAs, new primer pairs were designed to amplify specific short fragments of the genes cytb (548 bp fragment) and rrnL (200 bp fragment) in theB. procyonismtDNA, and tested as possible alternatives to existing mt molecular beacons for Ascaridida. Finally, phylogenetic analysis of mtDNAs provided novel estimates of the interrelationships of Baylisasaris and Ascaridida.
CONCLUSIONS/SIGNIFICANCE:The complete mtgenomesequence of B. procyonis sequenced here should contribute to molecular diagnostic methods, epidemiological investigations and ecological studies ofB. procyonisand other related ascaridoids. The information will be important in refining the phylogenetic relationships within the order Ascaridida and enriching the resource of markers for systematic, population genetic and evolutionary biological studies of parasitic nematodes of socio-economic importance.
Copyright © 2011 Xie et al.
PLoSOne.2011;6(10):e27066. doi: 10.1371/journal.pone.0027066. Epub 2011 Oct 28.
Read full text:http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0027066
