Wireless sensor networks are widely deployed for a wide range of applications for gathering information about the environment, monitoring huge building etc. However, the limited energy of the sensor nodes requires efficient gathering of information so that the network lifetime is increased. In literature it is proved that this efficiency can be achieved by clustering the sensor nodes in the network. Previously we proposed a single hop genetic based clustering protocol (GCA) for sensor networks. However, multi-hop routing techniques are known to be a practical approach to solving the problem of routing in sensor networks. In this paper, we present a new robust clustering based multi-hop routing protocol for wireless sensor networks. The proposed genetic clustering algorithm (M-GCA) employs evolutionary techniques to form an efficient virtual backbone. This backbone is used to support routing messages to the base station. Simulation results show that the proposed multi-hop routing protocol outperforms GCA, a single-hop clustering protocol in several scenarios.