Species delimitation and interspecific relationships of the endangered herb genus Notopterygium inferred from multilocus variations.
Species identification and discrimination is the basis of biodiversity research. In general, it is considered that numerous nucleotide variations (e.g., whole chloroplast genomes) can identify species with higher resolution than a few loci, e.g., partial chloroplast or nuclear gene fragments. In this study, we tested this hypothesis by sampling population genetics samples of the endangered herb genus Notopterygium. We sequenced the complete plastomes, five nuclear gene regions, three chloroplast DNA fragments, and a nuclear internal transcribed spacer (nrITS) region for 18 populations sampled throughout most of the geographic ranges of all six Notopterygium species. Species identification analysis showed that four DNA barcodes (matK, rbcL, trnS-trnG, and nrITS) and/or combinations of these markers achieved Notopterygium species discrimination at higher resolution than the general plastomes and nuclear gene sequences. In particular, nrITS had the highest discriminatory power among all of the individual markers. Molecular data sets and morphological evidence indicated that all six Notopterygium species could be reclassified unambiguously to four putative species clades. N. oviforme and N. franchetii had the closest relationship. Molecular dating showed that the origin and divergence of Notopterygium species was significantly associated with geological and climatic fluctuations during the middle of the Pliocene. In conclusion, our results suggest that a few nucleotide variations can achieve species discrimination with higher resolution than numerous plastomes and general nuclear gene fragments when discerning related Notopterygium species.
- NCBI accession MG197728; Hansenia oviformis voucher LH chloroplast, complete genome.
- NCBI accession MG197729; Hansenia oviformis voucher LF10 chloroplast, complete genome.
- NCBI accession MG197730; Hansenia oviformis voucher LG chloroplast, complete genome.
- NCBI accession MG197731; Hansenia weberbaueriana voucher HH2 chloroplast, complete genome.
- NCBI accession MG197732; Hansenia weberbaueriana voucher HI1 chloroplast, complete genome.
- NCBI accession MG197733; Hansenia weberbaueriana voucher A1 chloroplast, complete genome.
- NCBI accession MG197734; Hansenia weberbaueriana voucher M4 chloroplast, complete genome.
- NCBI accession MG197735; Hansenia weberbaueriana voucher X3 chloroplast, complete genome.
- NCBI accession MG197736; Hansenia forbesii voucher KM4 chloroplast, complete genome.
- NCBI accession MG197737; Hansenia forbesii voucher KG5 chloroplast, complete genome.
- NCBI accession MG197738; Hansenia forbesii voucher KI2 chloroplast, complete genome.
- NCBI accession MG197739; Hansenia forbesii voucher KF3 chloroplast, complete genome.
- NCBI accession MG197740; Hansenia forbesii voucher KX chloroplast, complete genome.
- NCBI accession MG197741; Hansenia forrestii voucher LQA5 chloroplast, complete genome.