Identification of a duplication of the mouse Lyn gene.

The Lyn gene encodes a PTK that is believed to participate in the transduction 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, sequences corresponding to the first coding exon are duplicated and this duplication extends into intron 10. Two sets of genomic clones representing the duplicated regions have been isolated and characterised. Nucleotide sequence analysis of these clones has revealed minimal sequence divergence between the two, suggesting that the duplication is a recent event. This is supported by Southern blot analysis of DNA from other mammalian species showing that the duplication is confined to the mouse. Aside from the duplicated sequences, the overall structure of the mouse Lyn gene is similar to that of other Src family members. These data suggest that the process of duplication which generated the Src family of PTK is an ongoing process and provide an insight into the molecular evolution of this group of genes.