Clonal interference, competition between multiple beneficial mutations, has a major role in adaptation of asexual populations. We provide a simple stochastic model of clonal interference taking into account a wide variety of competitive interactions. The population evolves as a three-type birth-and-death process with type dependent competitions. This allows us to relax the classical assumption of transitivity between mutations, and to predict genetic patterns, such as coexistence of several mutants or emergence of Rock-Paper-Scissors cycles, which were not explained by existing models. In addition, we call into questions some classical preconceived ideas about fixation time and fixation probability of competing mutations.