Exon/intron structure of aldehyde dehydrogenase genes supports the "introns-late" theory.

ABSTRACT: Whether or not nuclear introns predate the divergence of bacteria and eukaryotes is the central argument between the proponents of the "introns-early" and "introns-late" theories. In this study we compared the goodness-of-fit of each theory with a probabilistic model of exon/intron evolution and multiple nonallelic genes encoding human aldehyde dehydrogenases (ALDHs). Using a reconstructed phylogenetic tree of ALDH genes, we computed the likelihood of obtaining the present-day ALDH sequences under the assumptions of each competing theory. Although on the grounds of its own assumptions each theory accounted for the ALDH data significantly better than its rival, the introns-early model required frequent intron slippage, and the estimated slippage rates were too high to be consistent with rep

SUBMITTER: Rzhetsky A 

PROVIDER: S-EPMC21242 | biostudies-literature | 1997 Jun

REPOSITORIES: biostudies-literature