Dataset Information

Species Delimitation and Interspecific Relationships of the Genus Orychophragmus (Brassicaceae) Inferred from Whole Chloroplast Genomes.

ABSTRACT: Genetic variations from few chloroplast DNA fragments show lower discriminatory power in the delimitation of closely related species and less resolution ability in discerning interspecific relationships than from nrITS. Here we use Orychophragmus (Brassicaceae) as a model system to test the hypothesis that the whole chloroplast genomes (plastomes), with accumulation of more variations despite the slow evolution, can overcome these weaknesses. We used Illumina sequencing technology via a reference-guided assembly to construct complete plastomes of 17 individuals from six putatively assumed species in the genus. All plastomes are highly conserved in genome structure, gene order, and orientation, and they are around 153 kb in length and contain 113 unique genes. However, nucleotide variations are quite substantial to support the delimitation of all sampled species and to resolve interspecific relationships with high statistical supports. As expected, the estimated divergences between major clades and species are lower than those estimated from nrITS probably due to the slow substitution rate of the plastomes. However, the plastome and nrITS phylogenies were contradictory in the placements of most species, thus suggesting that these species may have experienced complex non-bifurcating evolutions with incomplete lineage sorting and/or hybrid introgressions. Overall, our case study highlights the importance of using plastomes to examine species boundaries and establish an independent phylogeny to infer the speciation history of plants.

SUBMITTER: Hu H

PROVIDER: S-EPMC5138468 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Publications

Species Delimitation and Interspecific Relationships of the Genus <i>Orychophragmus</i> (Brassicaceae) Inferred from Whole Chloroplast Genomes.

Hu Huan H Hu Quanjun Q Al-Shehbaz Ihsan A IA Luo Xin X Zeng Tingting T Guo Xinyi X Liu Jianquan J

Frontiers in plant science 20161206

Genetic variations from few chloroplast DNA fragments show lower discriminatory power in the delimitation of closely related species and less resolution ability in discerning interspecific relationships than from nrITS. Here we use <i>Orychophragmus</i> (Brassicaceae) as a model system to test the hypothesis that the whole chloroplast genomes (plastomes), with accumulation of more variations despite the slow evolution, can overcome these weaknesses. We used Illumina sequencing technology via a r ...[more]

PMID: 27999584

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Project description:BackgroundCommelinaceae (Commelinales) comprise 41 genera and are widely distributed in both the Old and New Worlds, except in Europe. The relationships among genera in this family have been suggested in several morphological and molecular studies. However, it is difficult to explain their relationships due to high morphological variations and low support values. Currently, many researchers have been using complete chloroplast genome data for inferring the evolution of land plants. In this study, we completed 15 new plastid genome sequences of subfamily Commelinoideae using the Mi-seq platform. We utilized genome data to reveal the structural variations and reconstruct the problematic positions of genera for the first time.ResultsAll examined species of Commelinoideae have three pseudogenes (accD, rpoA, and ycf15), and the former two might be a synapomorphy within Commelinales. Only four species in tribe Commelineae presented IR expansion, which affected duplication of the rpl22 gene. We identified inversions that range from approximately 3 to 15 kb in four taxa (Amischotolype, Belosynapsis, Murdannia, and Streptolirion). The phylogenetic analysis using 77 chloroplast protein-coding genes with maximum parsimony, maximum likelihood, and Bayesian inference suggests that Palisota is most closely related to tribe Commelineae, supported by high support values. This result differs significantly from the current classification of Commelinaceae. Also, we resolved the unclear position of Streptoliriinae and the monophyly of Dichorisandrinae. Among the ten CDS (ndhH, rpoC2, ndhA, rps3, ndhG, ndhD, ccsA, ndhF, matK, and ycf1), which have high nucleotide diversity values (Pi > 0.045) and over 500 bp length, four CDS (ndhH, rpoC2, matK, and ycf1) show that they are congruent with the topology derived from 77 chloroplast protein-coding genes.ConclusionsIn this study, we provide detailed information on the 15 complete plastid genomes of Commelinoideae taxa. We identified characteristic pseudogenes and nucleotide diversity, which can be used to infer the family evolutionary history. Also, further research is needed to revise the position of Palisota in the current classification of Commelinaceae.

Dataset Information

Species Delimitation and Interspecific Relationships of the Genus Orychophragmus (Brassicaceae) Inferred from Whole Chloroplast Genomes.

Publications

Species Delimitation and Interspecific Relationships of the Genus <i>Orychophragmus</i> (Brassicaceae) Inferred from Whole Chloroplast Genomes.

Similar Datasets

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