Biomaterial Database

Evolution of the intron-exon structure of eukaryotic genes. 1995

M Long, and S J de Souza, and W Gilbert

Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.

The origin and evolution of intron-exon structures continue to be controversial topics. Two alternative theories, the 'exon theory of genes' and the 'insertional theory of introns', debate the presence or absence of introns in primordial genes. Both sides of the argument have focused on the positions of introns with respect to protein and gene structures. A new approach has emerged in the study of the evolution of intron-exon structures: a population analysis of genes. One example is the statistical analysis of intron phases--the position of introns within or between codons. This analysis detected a significant signal of exon shuffling in the DNA sequence database containing both ancient and modern exon sequences: intron phase correlations, that is, the association together within genes of introns of the same phase. The results of this analysis suggest that exon shuffling played an important role in the origin of both ancient and modern genes.

UI	MeSH Term	Description	Entries
D007438	Introns	Sequences of DNA in the genes that are located between the EXONS. They are transcribed along with the exons but are removed from the primary gene transcript by RNA SPLICING to leave mature RNA. Some introns code for separate genes.	Intervening Sequences,Sequences, Intervening,Intervening Sequence,Intron,Sequence, Intervening
D008957	Models, Genetic	Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.	Genetic Models,Genetic Model,Model, Genetic
D003062	Codon	A set of three nucleotides in a protein coding sequence that specifies individual amino acids or a termination signal (CODON, TERMINATOR). Most codons are universal, but some organisms do not produce the transfer RNAs (RNA, TRANSFER) complementary to all codons. These codons are referred to as unassigned codons (CODONS, NONSENSE).	Codon, Sense,Sense Codon,Codons,Codons, Sense,Sense Codons
D005057	Eukaryotic Cells	Cells of the higher organisms, containing a true nucleus bounded by a nuclear membrane.	Cell, Eukaryotic,Cells, Eukaryotic,Eukaryotic Cell
D005075	Biological Evolution	The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.	Evolution, Biological
D005091	Exons	The parts of a transcript of a split GENE remaining after the INTRONS are removed. They are spliced together to become a MESSENGER RNA or other functional RNA.	Mini-Exon,Exon,Mini Exon,Mini-Exons
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia