Minaya, Miguel A. , Pimentel, Manuel , Mason-Gamer, Roberta , Catalan, Pilar .
Distribution and evolutionary dynamics of Stowaway Miniature Inverted repeat Transposable Elements (MITEs) in grasses.
The occurrence of Stowaway MITEs and their potential footprints in the grasses was assessed within an explicit phylogenetic framework. The Poaceae phylogeny was constructed based on two nuclear (B-amylase, ITS) and four plastid (matK, ndhF, trnT-L, trnL-F) genes. This tree was used to analyze the distribution and evolutionary dynamics of the Stowaway MITEs and their potential excision footprints at the fourth intron of the B-amylase gene. Three types of B-amylase Stowaway MITEs were found in 16 representatives of the Pooideae (9 Triticeae, and 7 from the Alopecurinae/ Poinae/ Puccinelliinae group): i) those with stem-and-loop secondary structure (in Aegilops comosa, Australopyrum retrofractum, A. velutinum, Crithopsis delileanus, Elymus repens, Henrardia persica, Peridiction sanctum, and Zingeria biebersteiniana); ii) those with stem-and-loop secondary structure with small additional insertions (in Catabrosa aquatica, Catabrosella araratica,Colpodium versicolor, Puccinellia distans, and Zingeria cochii); and iii) those that do not form a stem-and-loop secondary structure (in Aegilops uniaristata, Colpodium drakensbergense, and Lophopyrum elongatum). Megablast and discontiguous megablast searches in the Entrez nucleotide database showed that these elements were distributed in the introns and intergenic spacers of many other nuclear genes throughout the BEP lineages; however they were absent in the studied PACCMAD lineages. Potential MITE footprints were also found in representatives of another 22 BEP clade taxa but were absent in the 22 surveyed PACCMAD clade taxa. A plausible underlying dynamic of successive acquisitions and deletions of B-amylase Stowaway MITEs in the temperate grasses could be explained by three, non-mutually-exclusive, alternative hypotheses. The first hypothesis involves a single early acquisition of a palindrome element, similar to Tc1-Mariner, in the fourth intron of the B-amylase gene in the ancestor of the Pooideae, followed by multiple independent losses. The second hypothesis implies multiple independent acquisitions of MITEs in non-related pooid lineages. The third hypothesis suggests different waves of acquisitions of MITEs, followed by multiple losses and horizontal gene transfers in the temperate grasses. This last hypothesis seems to fit best with the evidence found to date.
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1 - Universidad de Zaragoza, Agricultura y Economía Agraria, Ctra. Cuarte Km 1, Huesca, Huesca, 22071, Spain
2 - Universidade da Coruña, Biología Animal, Biología Vegetal y Ecología, Campus da Zapateira s.n., A Coruña, A Coruña, 15071, Spain
3 - University of Illinois at Chicago, Biological Sciences, 840 West Taylor Street, Chicago, IL, 60607, USA
BEP and PACCMAD clades
Stowaway transferable elements.
Presentation Type: Poster:Posters for Topics
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM