title: Molecular barcodes for soil nematode identification.
abstract: Using a molecular barcode, derived from single-specimen polymerase chain reaction (PCR) and sequencing of the 5' segment of the small subunit ribosomal RNA (SSU) gene, we have developed a molecular operational taxonomic unit (MOTU) scheme for soil nematodes. Individual specimens were considered to belong to the same MOTU when the sequenced segment of 450 bases was > 99.5% identical. A Scottish upland Agrostis-Festuca grassland soil was sampled, using both culture-based and random selection methods. One hundred and sixty-six cultured isolates were sequenced, and clustered into five MOTU. From 74 randomly sampled individuals across the study site, 19 MOTU were defined. A subsequent sample of 18 individuals from a single subplot contained eight MOTU, four of which were unique to the single subplot sample. Interestingly, seven of these MOTU were not present in the culture-independent sampling. Overall, a total of 23 MOTU were defined from only 240 sequences. Many MOTU could readily be assigned to classical, morphologically defined taxonomic units using a database of SSU sequences from named nematode species. The MOTU technique allows a rapid assessment of nematode taxon diversity in soils. Correlation with a database of sequences from known species offers a route to application of the technique in ecological surveys addressing biological as well as genetic diversity.
authors.affiliation: Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh EH9 3JT, UK. Robin.Floyd@ed.ac.uk
authors.forename: Robin
authors.initials: R
authors.lastname: Floyd
authors.forename: Eyualem
authors.initials: E
authors.lastname: Abebe
authors.forename: Artemis
authors.initials: A
authors.lastname: Papert
authors.forename: Mark
authors.initials: M
authors.lastname: Blaxter
mesh_terms: D000818:Animals; D004275:DNA, Ribosomal / Q000032:analysis* / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics*; D009348:Nematoda / Q000145:classification* / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012337:RNA, Ribosomal, 18S / Q000235:genetics*; D017422:Sequence Analysis, DNA; D012987:Soil / Q000469:parasitology*
chemical_list: D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S; D012987:Soil