RT Journal
A1 Fedorov, Alexei
A1 Roy, Scott
A1 Cao, Xiaohong
A1 Gilbert, Walter
T1 Phylogenetically Older Introns Strongly Correlate With Module Boundaries in Ancient Proteins
JF Genome Research 
JO Genome Research 
YR 2003 
FD June 01 
VO 13 
IS 6a 
SP 1155 
OP 1157 
DO 10.1101/gr.1008203 
UL http://genome.cshlp.org/content/13/6a/1155.abstract 
AB The hypothesis that some (but not all) introns were used to construct  ancient genes by exon shuffling of modules at the earliest stages of evolution  is supported by the finding of an excess of phase-zero intron positions in the  boundary regions of such modules in 276 ancient proteins (defined as common to  eukaryotes and prokaryotes). Here we show further that as phase-zero intron  positions are shared by distant taxa, and thus are truly phylogenetically  ancient, their excess in the boundaries becomes greater, rising to an 80%  excess if shared by four out of the five taxa: vertebrates, invertebrates,  fungi, plants, and protists.