Summary: Selection for Modularity in the Genome:
Reading Frame Evidence for Exon Shuffling ?
Lee Altenberg ??
Douglas Brutlag ???
Department of Biochemistry
Stanford, CA 94305 U.S.A.
Key Words: exon shuffling, modularity, reading frame, evolution
Abstract. During the addition of new, adaptive genes to the genome, if certain
sequences are better donors in creating new genes than others, then a kind of
selection process results that can improve the ability of the genome to generate
new, useful genes. When applied to the evolution of exons, this idea predicts that
there should be a predominance, among translated exons, of exons and pairs of
exons that are multiples of 3 bases in length. It also predicts that more introns
should fall between codons rather than splitting them. Empirical verification of
these predictions is described.
In the ``Modern Synthesis'' of evolutionary theory, evolution is usually taken to proceed
through substitutions in the alleles of a gene. Yet some fraction of the time, adaptations