Systematic repeat addition at a precise location in the coding region of the involucrin gene of wild mice reveals their phylogeny.
The involucrin gene encodes a protein of terminally differentiated keratinocytes. Its segment of repeats, which represents up to 80% of the coding region, is highly polymorphic in mouse strains derived from wild progenitors. Polymorphism includes nucleotide substitutions, but is most strikingly due to the recent addition of a variable number of repeats at a precise location within the segment of repeats. Each mouse taxon examined showed consistent and distinctive patterns of evolution of its variable region: very rapid changes in most M. m. domesticus alleles, slow changes in M. m. musculus, and complete arrest in M. spretus. We conclude that changes in the variable region are controlled by the genetic background. One of the M. m. domesticus alleles (DIK-L), which is of M. m. musculus origin, has undergone a recent repeat duplication typical of M. m. domesticus. This suggests that the genetic background controls repeat duplications through trans-acting factors. Because the repeat pattern differs in closely related murine taxa, involucrin reveals with greater sensitivity than random nucleotide substitutions the evolutionary relations of the mouse and probably of all murids.
Djian
Philippe
P
Régulation de la Transcription et Maladies Génétiques, UPR 2228 Centre National de la Recherche Scientifique, Université René Descartes, Paris, France. philippe.djian@univ-paris5.fr
Delhomme
Brigitte
B
D000483:Alleles; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002454:Cell Differentiation; D019070:Cell Lineage; D019143:Evolution, Molecular; D015603:Keratinocytes / Q000378:metabolism; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011498:Protein Precursors / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
D011498:Protein Precursors; C032253:involucrin