Chloroplast Genome Assembly and Phylogenetic Analysis of Dalbergia Oligophylla Baker ex Hutch & Dalziel, a Range-Restricted, CITES-Protected Timber Species

Dalbergia oligophylla is a rare and ecologically significant tree species native to West Africa, currently facing threats from habitat degradation and illegal logging. Here, we present the complete chloroplast genome sequence and phylogenetic analysis of D. oligophylla. The chloroplast genome was assembled and annotated using nextgeneration sequencing (NGS) technology. The base composition of D. oligophylla chloroplast genomes provide insight into their evolutionary relationships and genome stability. The genome size of D. oligophylla is (159,300 bp), and the organization of the genome into Large Single Copy (LSC), Small Single Copy (SSC), and Inverted Repeat (IR) regions is 89,046 bp, the IR region is highly conserved, with 25,648 bp, while the SSC region is the smallest with 18,985 respectively. In terms of nucleotide composition, have a relatively balanced distribution of adenine (A) and thymine (T) bases, showing 31.9% A and 31.8% T, Guanine (G) and cytosine (C) contents are lower, with 18.2% G and 18.1% C. Selective pressure analysis identified positively selected genes, including ycf1, rbcL, and accD, which may have adaptive significance in response to environmental pressures. Additionally, variable hotspot regions were detected, which may serve as molecular markers for species identification and conservation management. This study reported and deposited the complete chloroplast genome sequence of D. oligophylla for evolutionary studies in Fabaceae.

genetic distance, phylogeny, Dalbergia oligophylla plastome

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