Open AccessEvidence for gene conversion in genes for cell-adhesion molecules.
Author(s) -
Joseph A. Gally,
Gerald M. Edelman
Publication year - 1992
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.89.8.3276
Subject(s) - exon , intron , gene , tandem exon duplication , biology , genetics , exon shuffling , gene duplication , genomic dna , exon trapping , alternative splicing
The genomic sequences encoding a chicken Ca(2+)-dependent cell adhesion molecule (K-CAM) were recently found to be located approximately 600 base pairs upstream from the translation initiation site of a homologous protein, liver CAM. The sizes of 11 exons of the K-CAM gene are almost identical to those in the L-CAM (liver cell-adhesion molecule) gene with exon-intron junctions occurring at exactly equivalent positions. The sizes and sequences of most introns were, however, much more dissimilar. More detailed comparisons of these two genes reveal that the sequences of the last two exons (exons 15 and 16) are far more alike than are any of the other exons; they are, in fact, almost identical. The introns that separate these exons in the two genes likewise resemble one another far more than do any other corresponding introns. This degree of similarity appears to be far greater than can be accounted for by selection for protein structure, and it strongly suggests that a gene conversion event occurred between these two genes subsequent to their duplication and divergence to perform different biological functions.