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Citation for Study 19731

Citation title: "Phylogeny of Najas (Hydrocharitaceae) revisited: Implications for systematics and evolution".

Study name: "Phylogeny of Najas (Hydrocharitaceae) revisited: Implications for systematics and evolution".

This study is part of submission 19731 (Status: Published).

Citation

Ito Y., Tanaka N., Gale S.W., Yano O., & Li J. 2017. Phylogeny of Najas (Hydrocharitaceae) revisited: Implications for systematics and evolution. Taxon, 66(2): 309?323.

Authors

• Ito Y.
• Tanaka N.
• Gale S.W.
• Yano O.
• Li J.

Abstract

Najas (Hydrocharitaceae) is a cosmopolitan genus of 30?40 species of aquatic plants. While an infrageneric subdivision into two subgenera is generally accepted, various sectional classifications proposed in subg. Caulinia have been controversial. Earlier analyses identified tropical Asia, which harbors more than one-third of all species, as the area of origin for the genus, but this inference requires re-evaluation using worldwide taxon sampling. Polyploidy has been widely observed in the genus but its correlation with phylogeny has yet to be explored. Here we applied a molecular phylogenetic approach using balanced taxon sampling (1) to test infrageneric classifications, (2) to re-assess biogeographic origin, and (3) to explore whether and how polyploidy characterizes evolutionary lineages. Our analyses of plastid and nuclear (ITS) DNA datasets produce largely congruent results that recover the two subgenera but find little support for most sectional classifications. To overcome this shortfall, we propose a new sectional classification of subg. Caulinia. The previously inferred tropical Asian origin of the genus is rejected and, instead, North America is discerned as the ancestral area, implicating dispersal of the most recent common ancestor of Najas and its sister genera in Hydrocharitaceae from tropical Asia. Based on chromosome counts confirmed in the present study and those compiled from literature, the role of polyploidization in the evolution of Najas is shown to be relatively limited, in contrast to the extreme infraspecific chromosome variation previously reported.

Keywords

aquatic plants; biogeography; chromosome counts; molecular phylogeny; monocots; polyploidy

External links

• DOI: 10.12705/662.2

About this resource

• Canonical resource URI: http://purl.org/phylo/treebase/phylows/study/TB2:S19731
• Other versions: Nexus NeXML
• Show BibTeX reference

  		@ARTICLE{TreeBASE2Ref27419,
  	 author = {Yu  Ito and Norio  Tanaka and Stephan W. Gale and Okihito  Yano and Jie  Li},
  	 title = {Phylogeny of Najas (Hydrocharitaceae) revisited: Implications for systematics and evolution},
  	 year = {2017},
  	 keywords = {aquatic plants; biogeography; chromosome counts; molecular phylogeny; monocots; polyploidy},
  	 doi = {10.12705/662.2},
  	 url = {http://},
  	 pmid = {},
  	 journal = {Taxon},
  	 volume = {66},
  	 number = {2},
  	 pages = {309?323},
  	 abstract = {Najas (Hydrocharitaceae) is a cosmopolitan genus of 30?40 species of aquatic plants. While an infrageneric subdivision
  into two subgenera is generally accepted, various sectional classifications proposed in subg. Caulinia have been controversial.
  Earlier analyses identified tropical Asia, which harbors more than one-third of all species, as the area of origin for the genus,
  but this inference requires re-evaluation using worldwide taxon sampling. Polyploidy has been widely observed in the genus
  but its correlation with phylogeny has yet to be explored. Here we applied a molecular phylogenetic approach using balanced
  taxon sampling (1) to test infrageneric classifications, (2) to re-assess biogeographic origin, and (3) to explore whether and
  how polyploidy characterizes evolutionary lineages. Our analyses of plastid and nuclear (ITS) DNA datasets produce largely
  congruent results that recover the two subgenera but find little support for most sectional classifications. To overcome this
  shortfall, we propose a new sectional classification of subg. Caulinia. The previously inferred tropical Asian origin of the genus
  is rejected and, instead, North America is discerned as the ancestral area, implicating dispersal of the most recent common
  ancestor of Najas and its sister genera in Hydrocharitaceae from tropical Asia. Based on chromosome counts confirmed in the
  present study and those compiled from literature, the role of polyploidization in the evolution of Najas is shown to be relatively
  limited, in contrast to the extreme infraspecific chromosome variation previously reported.}
  }
  		

• Show RIS reference

  		TY  - JOUR
  ID  - 27419
  AU  - Ito,Yu 
  AU  - Tanaka,Norio 
  AU  - Gale,Stephan W.
  AU  - Yano,Okihito 
  AU  - Li,Jie 
  T1  - Phylogeny of Najas (Hydrocharitaceae) revisited: Implications for systematics and evolution
  PY  - 2017
  KW  - aquatic plants; biogeography; chromosome counts; molecular phylogeny; monocots; polyploidy
  UR  - http://dx.doi.org/10.12705/662.2
  N2  - Najas (Hydrocharitaceae) is a cosmopolitan genus of 30?40 species of aquatic plants. While an infrageneric subdivision
  into two subgenera is generally accepted, various sectional classifications proposed in subg. Caulinia have been controversial.
  Earlier analyses identified tropical Asia, which harbors more than one-third of all species, as the area of origin for the genus,
  but this inference requires re-evaluation using worldwide taxon sampling. Polyploidy has been widely observed in the genus
  but its correlation with phylogeny has yet to be explored. Here we applied a molecular phylogenetic approach using balanced
  taxon sampling (1) to test infrageneric classifications, (2) to re-assess biogeographic origin, and (3) to explore whether and
  how polyploidy characterizes evolutionary lineages. Our analyses of plastid and nuclear (ITS) DNA datasets produce largely
  congruent results that recover the two subgenera but find little support for most sectional classifications. To overcome this
  shortfall, we propose a new sectional classification of subg. Caulinia. The previously inferred tropical Asian origin of the genus
  is rejected and, instead, North America is discerned as the ancestral area, implicating dispersal of the most recent common
  ancestor of Najas and its sister genera in Hydrocharitaceae from tropical Asia. Based on chromosome counts confirmed in the
  present study and those compiled from literature, the role of polyploidization in the evolution of Najas is shown to be relatively
  limited, in contrast to the extreme infraspecific chromosome variation previously reported.
  L3  - 10.12705/662.2
  JF  - Taxon
  VL  - 66
  IS  - 2
  ER  -