@ARTICLE{TreeBASE2Ref16340, author = {Jianhua Li and Suzanne Shoup and Zhiduan Chen}, title = {Phylogenetic Relationships of Diploid Species of Betula (Betulaceae) Inferred from Nuclear Nitrogen Reductase}, year = {2007}, keywords = {}, doi = {}, url = {}, pmid = {}, journal = {Systematic Botany}, volume = {}, number = {}, pages = {}, abstract = {Frequent occurrence of ancient hybridization and introgression in the evolutionary history of Betula has made it prone to errors to use chloroplast genes to infer interspecific relationships. Single and low copy genes, however, may offer some hope for accurately reconstructing phylogenetic relationships of Betula and inferring the origin of polyploidy species. In this study sequences of the third intron of the nuclear nitrogen reductase (NIA) were used to estimate relationships of known diploid species of Betula. Two types of the NIA gene were observed in Betula that differed considerably. Sequences of the first type were gathered from all sampled species, while those of the second type were obtained from only B. lenta and B. nana and were not included in phylogenetic analyses. Clone sequences of the NIA gene varied little within individual or species. Maximum parsimony and likelihood analyses generated robust phylogenies with similar relationships. Betula alnoides and B. maximowicziana of subgenus Betulaster formed a well supported clade, which is characterized by the racemose arrangement of pistillate inflorescence. Shrubby species (B. nana and B. michauxii) of a traditionally recognized group did not form a clade. Instead, B. nana was most closely related to white-barked species (e.g., B. pendula, B. platyphylla, and B. populifolia) and together they were clustered with B. nigra. In constrast, B. michauxii is closely allied with B. lenta. Our results suggest that subgenera Betulaster and Betula are monophyletic, while subgenera Chamaebetula, Neurobetula, and Betulenta are polyphyletic.} }

• Go to search
• Citation
• Taxa
• Matrices
• Trees
• Analyses
• 

CiteULike

Delicious

Connotea