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Nuclear simple sequence repeat markers are superior to DNA barcodes for identification of closely related Rhododendron species on the same mountain
Author(s) -
Wang Ji,
Luo Jian,
Ma YaZhen,
Mao XingXing,
Liu JianQuan
Publication year - 2019
Publication title -
journal of systematics and evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.249
H-Index - 46
eISSN - 1759-6831
pISSN - 1674-4918
DOI - 10.1111/jse.12460
Subject(s) - biology , introgression , coalescent theory , species complex , internal transcribed spacer , dna barcoding , microsatellite , evolutionary biology , lineage (genetic) , dna sequencing , gene flow , hybrid , identification (biology) , genetic marker , genetics , phylogenetics , dna , gene , botany , genetic variation , phylogenetic tree , allele
Accurate species delimitation of sampled biological material is critical for a range of studies. Although the DNA barcodes developed in recent years are useful for identifying numerous well differentiated species that have not experienced frequent gene flow, they fail to delimit recently diverged species, especially those with extensive introgressions. Here we use five Rhododendron species growing together on the same mountain as a model system to compare the species delimitation effectiveness of the DNA barcodes (internal transcribed spacer, matK , psbA‐trnH , and rbcL ) previously proposed versus 15 pairs of microsatellite markers. Using these markers, we genotyped 129 individuals, which were members of five species according to morphological identification. We identified five simple sequence repeat genetic clusters (independently evolving lineages) corresponding to the morphological identification. However, we found that numerous individuals contained cryptic hybrid introgressions from the other species. The four DNA barcodes could not delimit three out of four closely related species that showed clear morphological differentiation and cryptic introgressions. Even after excluding all cryptic hybrids, two closely related species could not be successfully identified. The low discrimination ability of the DNA barcodes for closely related Rhododendron species could result from two, not mutually exclusive factors: introgressive hybridization and incomplete lineage sorting. Our results highlight the importance of simple sequence repeat markers in delimiting closely related species and identifying cryptic introgressions in the absence of morphological changes.