In this paper, we focus on Wireless Sensor Networks (WSNs) in a more realistic case than classical studies and pre- vious works: we consider wireless sensor nodes having different transmission ranges according to the environment and/or to the wireless chipset. The main consequence of this heterogeneity is the existence of asymmetric links. Such links in a WSN degrade the performance of most protocols which have not been designed to support this heterogeneity and to deal with asymmetric links: so, mainly, these links are pruned. Under this assumption, we propose a routing protocol for data collection from sensors nodes to the sink node in heterogeneous WSNs. Our proposal detects and takes benefit from asymmetric links caused by this heterogeneity. Our proposal, denoted MURA, (1) provides a high delivery ratio, (2) reduces the number of duplicated packets and (3) reduces the number of hop counts by exploiting the asymmetric links.