Evidence map›Paper›PMID 42265602›Full record

ArticleBMC plant biology2026

Comparative chloroplast genomics of 22 species of Sida (Malvaceae) reveals structural conservation, adaptive evolution, and preliminary phylogenetic structure.

Rushan Yan, Abdul Sammad, Sayed Afzal Shah, Atinga Vallada, Xiaoxuan Tian, Abdullah

Abstract readComparative Study
In one paragraph

Article in BMC plant biology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

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1 · What the graph read from it

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3 · Its place in the literature

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1 citing paper in PubMed.

  1. Plastome evidence repositionsFrontiers in plant science · 2026
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4 · The record

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5 · Who and what money

Authors and funding

6 authors.

Rushan Yan *State Key Laboratory of Chinese Medicine Modernization, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China.
Abdul Sammad *State Key Laboratory of Chinese Medicine Modernization, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China.
Sayed Afzal ShahDepartment of Biological Sciences, National University of Medical Sciences, Rawalpindi, Pakistan.
Atinga ValladaDepartment of Pharmacognosy and Drug Development, Gombe State University, Gombe, Gombe, 760214, Nigeria. pharmvalat484@gsu.edu.ng.
Xiaoxuan TianState Key Laboratory of Chinese Medicine Modernization, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China. tian_xiaoxuan@tjutcm.edu.cn.
AbdullahState Key Laboratory of Chinese Medicine Modernization, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China. abdullah@tjutcm.edu.cn.ORCID http://orcid.org/0000-0003-1628-8478

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundThe genus Sida L. (Malvoideae, Malvaceae) comprises 275 species with a near-cosmopolitan distribution. Persistent taxonomic uncertainties, driven by morphological complexity and low resolution of traditional molecular markers, hinder systematic understanding of the genus. Chloroplast (cp) genomes provide genome-scale data capable of resolving these taxonomic uncertainties, but genomic resources for Sida remain limited. Here, we substantially expand cp genome sampling, perform comparative and selection analyses, identify candidate loci for species discrimination and phylogenetic inference, and conduct phylogenomic inference to clarify infrageneric relationships.

resultsWe sequenced and de novo assembled the complete cp genomes of Sida cordata (Burm.f.) Borss.Waalk. and Sida rhombifolia L., and assembled cp genomes of 18 additional species de novo from publicly available raw sequencing reads. Together with two previously reported cp genomes, 22 cp genomes were subjected to comparative and phylogenetic analyses. Genome sizes ranged from 159,706 to 160,513 base pairs (bp), comprising a large single-copy region (88,771-89,551 bp), inverted repeats (IRa/IRb; 25,288-25,640 bp), and a small single-copy region (19,863-20,294 bp). Each genome contained 113 unique genes (79 protein-coding, 30 tRNAs, 4 rRNAs). Comparative analyses revealed conserved gene order, guanine-cytosine content, codon usage, and simple sequence repeat composition, as well as a consistent transition bias in substitution patterns across all Sida species. Gene-level selection analyses identified episodic positive selection in psaB, psbB, rbcL, and rps8, while site-level analyses detected positive selection at specific codons in rbcL and ycf1. Ten highly polymorphic loci with elevated nucleotide diversity and low missing data were identified as candidates for species identification and phylogenetic inference, including psbT-psbN, ndhD-psaC, psaC-ndhE, rps15-ycf1, and psaI. Phylogenetic analysis of the 22 species resolved two strongly supported clades: a monophyletic endemic Australian lineage and a broadly distributed Asian/pantropical lineage.

conclusionsOur findings reveal conserved cp genome structure across 22 Sida cp genomes, identify polymorphic loci as potential barcodes, and resolve two clades (an endemic Australian lineage and a widespread Asian/pantropical lineage), demonstrating the value of whole-cp genome data. However, due to sampling limitations and sole reliance on the maternally inherited cp genome, we recommend that future studies refine biogeographic inferences using denser taxon sampling and nuclear genomic data.

Indexed as

Evolution, MolecularGenome, ChloroplastMalvaceaePhylogenyGenomicsAdaptive evolutionChloroplast genomeComparative genomicsNucleotide polymorphismPhylogenomicsSida

Identifiers

PMID42265602
PMCPMC13471173

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