Writing - Teaching Genres

Today at staff meeting there was some discussion around teaching genre's again. I really like the idea of teaching the genres through reading and then letting the students use the reading as models to support them when choosing an appropriate text type for the purpose. Currently in our class we don't really explictly teach genre at all, rather teach what is needed depending on the purpose. However, we don't then link that to different text types in books. I wonder whether this is necessary at our level anyway?