Intron Phase Patterns in Genes: Preservation and Evolutionary Changes

摘要

Introns are located either between codons (phase 0) or within codons (phase 1 and 2) and their phases as well aslocation usually stay unchanged for a long time. A string of intron phases represents a structure which may carry usefuladditional information about internal rearrangements of a gene. Combined search for intron phase patterns and exonlengths serves as a helpful approach for finding conserved intragenic duplications and other rearrangements. In vertebrategenes intragenic duplications usually are more numerous than in orthologs from other animal taxons. Intron phase patternsand exon lengths are highly conservative in some genes and can be traced back to a common ancestor of mammals andnematodes. Despite this, there are orthologs which show drastic losses of intron-exon structures as found in insects andurochordata. Driving forces behind such changes in exon-intron structures remain unknown and need further investigation.