Data/hora: 06/06/2024 12:56:50

Provedor de dados: 	5	
País: 	France	
Título: 	Low Evolutionary Diversification in a Widespread and Abundant Uncultured Protist (MAST-4)	
Autores: 	Rodriguez-martinez, Raquel; Rocap, Gabrielle; Logares, Ramiro; Romac, Sarah; Massana, Ramon.	
Data: 	2012-05	
Ano: 	2012	
Palavras-chave: 	MAST-4; Low evolutionary diversification; Uncultured protist; Pyrosequencing; ITS secondary structure.	
Resumo: 	Recent culture-independent studies of marine planktonic protists have unveiled a large diversity at all phylogenetic scales and the existence of novel groups. MAST-4 represents one of these novel uncultured lineages, and it is composed of small (similar to 2 mu m) bacterivorous eukaryotes that are widely distributed in marine systems. MAST-4 accounts for a significant fraction of the marine heterotrophic flagellates at the global level, playing key roles in the marine ecological network. In this study, we investigated the diversity of MAST-4, aiming to assess its limits and structure. Using ribosomal DNA (rDNA) sequences obtained in this study (both pyrosequencing reads and clones with large rDNA operon coverage), complemented with GenBank sequences, we show that MAST-4 is composed of only five main clades, which are well supported by small subunit and large subunit phylogenies. The differences in the conserved regions of the internal transcribed spacers 1 and 2 (ITS1 and ITS2) secondary structures strongly suggest that these five clades are different biological species. Based on intraclade divergence, ITS secondary structures and comparisons of ITS1 and ITS2 trees, we did not find evidence of more than one species within clade A, whereas as many as three species might be present within other clades. Overall, the genetic divergence of MAST-4 was surprisingly low for an organism with a global population size estimated to be around 10(24), indicating a very low evolutionary diversification within the group.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	https://archimer.ifremer.fr/doc/00374/48506/48778.pdf

DOI:10.1093/molbev/msr303

https://archimer.ifremer.fr/doc/00374/48506/	
Editor: 	Oxford Univ Press	
Formato: 	application/pdf	
Fonte: 	Molecular Biology And Evolution (0737-4038) (Oxford Univ Press), 2012-05 , Vol. 29 , N. 5 , P. 1393-1406	
Fonte: 	The Author 2011. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved.

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