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    Dorsal fin morphology and phylogenetic insights in bamboo sharks (Chiloscyllium spp.)
    (2026-05-01)
    Laongdee, P.
    ;
    Krajangdara, T.
    ;
    Senanan, W.
    ;
    Khudamrongsawat, J.
    ;
    Panithanarak, T.
    Two closely related species, C. hasseltii and C. griseum, showed overlapping shape variations in their first dorsal fins. However, the proportions of the first dorsal fin height/total length and the first dorsal fin inner margin/total length were observed to be significantly different between these two species. This difference can be integrated into the dichotomous key for Chiloscyllium. Phylogenetic analysis based on the cytochrome c oxidase I (COI) gene was consistent with the morphology of the first dorsal fin, indicating that C. punctatum differs from other Chiloscyllium species. However, phylogenetic tree based on the NADH dehydrogenase 2 (ND2) gene fragments grouped the clade of C. punctatum with other clades of Chiloscyllium. Most Chiloscyllium species formed monophyletic groups based on the two gene fragments, except for C. hasseltii and C. griseum, which clustered together. This research provides practical knowledge for field-based species identification and accurate classification within the genus Chiloscyllium, enhances our understanding of its phylogenetic relationships, and supports the future development of a field guide.
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    Molecular genetic diversity of Bambara groundnut (Vigna subterranea L. Verdc.) revealed by rapd and ISSR marker analysis
    (2012-12-13)
    Rungnoi, O.
    ;
    Suwanprasert, J.
    ;
    Somta, P.
    ;
    Srinives, P.
    A set of 363 Bambara groundnut (Vigna subterranea L. Verdc.) accessions from five geographical regions and unknown origin was assessed with 65 loci generated from inter simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) markers to provide more information on genetic diversity and origin. Higher percentage of polymorphic DNA bands, gene diversity and Shannon's diversity index were found in accessions from Cameroon/Nigeria and West Africa regions but not much different from those found in accessions from West Africa. Genetic distance revealed close genetic relationships between accessions from Cameroon/Nigeria and West Africa regions. Hierarchical cluster analysis revealed that Thai Bambara groundnuts are clustered with both West and East Africa regions. Principal coordinate analysis demonstrated that accessions from Cameroon/Nigeria and West Africa were separated into two groups, where accessions from the two regions were mingled with each others. Although most accessions from East Africa were grouped with a cluster of Cameroon/Nigeria and West Africa accessions. Population structure analysis grouped the germplasm into two subpopulations where most accessions were in one subpopulation and 11 accessions were in the other subpopulation. Altogether, the results support the views that West Africa (including Cameroon and Nigeria) is the center of diversity of Bambara groundnut. The crop was introduced from West to East Africa, from where the Thai accessions were introduced.
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    Molecular phylogenetics of porcini mushrooms (Boletus section Boletus)
    (2010-01-01)
    Dentinger, Bryn T.M.
    ;
    Ammirati, Joseph F.
    ;
    Both, Ernst E.
    ;
    Desjardin, Dennis E.
    ;
    Halling, Roy E.
    Porcini (Boletus section Boletus: Boletaceae: Boletineae: Boletales) are a conspicuous group of wild, edible mushrooms characterized by fleshy fruiting bodies with a poroid hymenophore that is "stuffed" with white hyphae when young. Their reported distribution is with ectomycorrhizal plants throughout the Northern Hemisphere. Little progress has been made on the systematics of this group using modern molecular phylogenetic tools because sampling has been limited primarily to European species and the genes employed were insufficient to resolve the phylogeny. We examined the evolutionary history of porcini by using a global geographic sampling of most known species, new discoveries from little explored areas, and multiple genes. We used 78 sequences from the fast-evolving nuclear internal transcribed spacers and are able to recognize 18 reciprocally monophyletic species. To address whether or not porcini form a monophyletic group, we compiled a broadly sampled dataset of 41 taxa, including other members of the Boletineae, and used separate and combined phylogenetic analysis of sequences from the nuclear large subunit ribosomal DNA, the largest subunit of RNA polymerase II, and the mitochondrial ATPase subunit six gene. Contrary to previous studies, our separate and combined phylogenetic analyses support the monophyly of porcini. We also report the discovery of two taxa that expand the known distribution of porcini to Australia and Thailand and have ancient phylogenetic connections to the rest of the group. A relaxed molecular clock analysis with these new taxa dates the origin of porcini to between 42 and 54 million years ago, coinciding with the initial diversification of angiosperms, during the Eocene epoch when the climate was warm and humid. These results reveal an unexpected diversity, distribution, and ancient origin of a group of commercially valuable mushrooms that may provide an economic incentive for conservation and support the hypothesis of a tropical origin of the ectomycorrhizal symbiosis. © 2010 Elsevier Inc.