Evidence for transitional stages in the evolution of euglenid group II introns and twintrons in the Monomorphina aenigmatica plastid genome.

ABSTRACT:

Background

Photosynthetic euglenids acquired their plastid by secondary endosymbiosis of a prasinophyte-like green alga. But unlike its prasinophyte counterparts, the plastid genome of the euglenid Euglena gracilis is riddled with introns that interrupt almost every protein-encoding gene. The atypical group II introns and twintrons (introns-within-introns) found in the E. gracilis plastid have been hypothesized to have been acquired late in the evolution of euglenids, implying that massive numbers of introns may be lacking in other taxa. This late emergence was recently corroborated by the plastid genome sequences of the two basal euglenids, Eutreptiella gymnastica and Eutreptia viridis, which were found to contain fewer introns.

Methodology/principal findings

To gain furthe

SUBMITTER: Pombert JF 

PROVIDER: S-EPMC3534033 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature