A spliceosomal intron in Giardia lamblia

Short introns occur in numerous protist lineages, but there are no reports of intervening sequences in the protists Giardia lamblia and Trichomonas vaginalis, which may represent the deepest known branches in the eukaryotic line of descent. We have discovered a 35-bp spliceosomal intron in a gene encoding a putative [2Fe-2S] ferredoxin of G. lamblia. The Giardia intron contains a canonical splice site at its 3' end (AG), a noncanonical splice …