Authors: ARAMIDE OSHINGBOYE, GEORGE NODZA, TEMITOPE ONUMINYA, OLUWATOYIN OGUNDIPE
Abstract: The genus Afzelia Sm. (Fabaceae) represents one of the most useful tree species in tropical Africa. These trees have huge socioeconomic and ecological importance, but are under serious threat from incessant exploitation. This has caused a decline of the species in the wild; several species are now registered as threatened and endangered in the IUCN red list. However, conserving this species for posterity has been hampered by the complexity of morphological characters that exist among Afzelia species. In our study, we evaluated the utility of rbcL as a single barcode region, exploring its performance to accurately identify Nigerian Afzelia species and elucidate the relationships that exist between species. Our results revealed an overlap between intraspecific distance and interspecific divergence with an overall mean distance of 0.002. Likewise, identification based on all species barcode, best match, and best close match analysis of TaxonDNA depicted 46.15% and 57.14% of correct and ambiguous identification, respectively. Correct identification according to all species barcodes accurately identified 64.3% of data. Phylogenetic analysis based on UPGMA, NJ, MP, and BI analysis supports the monophyly of Afzelia with support values at 98%, 100%, 93.41%, and 1, respectively. It also revealed noncongruence among species of A. africana Pers. and A. quanzensis Welw., which suggests an unclear relationship between A. africana and its sister species. This implies rbcL is not an ideal plant barcode region for successful identification of Nigerian Afzelia species.
Keywords: Afzelia, conservation, DNA barcodes, IUCN, plant identification
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