IDENTIFICATION OF A DUPLICATION OF THE MOUSE LYN GENE

The Lyn gene encodes a PTK that is believed to participate in the tran sduction of signals from a variety of cell membrane receptors. Here we report the genomic organisation of the mouse Lyn gene and show that, while the promoter and exons 11-13 are present in single copy, sequenc es corresponding to the first coding exon are duplicated and this dupl ication extends into intron 10. Two sets of genomic clones representin g the duplicated regions have been isolated and characterised. Nucleot ide sequence analysis of these clones has revealed minimal sequence di vergence between the two, suggesting that the duplication is a recent event. This is supported by Southern blot analysis of DNA from other m ammalian species showing that the duplication is confined to the mouse . Aside from the duplicated sequences, the overall structure of the mo use Lyn gene is similar to that of other Src family members. These dat a suggest that the process of duplication which generated the Src fami ly of PTK is an ongoing process and provide an insight into the molecu lar evolution of this group of genes.