Genes give rise to phenes. Genes are the biochemical instructions encoding what an organism "can" be, while phenes are what the organism "is". In general it takes a combination of particular genes, environmental influences and random variation to give rise to any one phene in an organism. Both phenes and genes are subject to evolution. However, if one defines "genes" as "DNA sequences encoding polypeptides", they are not directly accessible to natural selection; the associated phenes are. Note that some, e.g. Richard Dawkins, have used a wider definition of "gene" than the one used in genetics on occasion, extending it to any DNA sequence with a function.