Eukaryotic evolution: early origin of canonical introns.
Spliceosomal introns, one of the hallmarks of eukaryotic genomes, were thought to have originated late in evolution and were assumed not to exist in eukaryotes that diverged early -- until the discovery of a single intron with an aberrant splice boundary in the primitive 'protozoan' Giardia. Here we describe introns from a close relative of Giardia, Carpediemonas membranifera, that have boundary sequences of the normal eukaryotic type, indicating that canonical introns are likely to have arisen very early in eukaryotic evolution.
Simpson
Alastair G B
AG
Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada. simpson@hades.biochem.da.ca
MacQuarrie
Erin K
EK
Roger
Andrew J
AJ
D000818:Animals; D001483:Base Sequence; D005057:Eukaryotic Cells / Q000145:classification* / Q000378:metabolism*; D019143:Evolution, Molecular; D005872:Giardia / Q000235:genetics; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D007438:Introns / Q000235:genetics*; D017851:Phosphotransferases (Carboxyl Group Acceptor) / Q000235:genetics*; D010802:Phylogeny; D022821:RNA Splice Sites / Q000235:genetics; D012326:RNA Splicing / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D018840:HSP70 Heat-Shock Proteins; D022821:RNA Splice Sites; D012333:RNA, Messenger; D017851:Phosphotransferases (Carboxyl Group Acceptor); C019288:carbamate kinase