To generate phylogenetic trees and investigate relationships between organisms, scientists usually look for similarities and differences in the DNA. Plant scientists were confounded by the fact that the DNA extracted from the plants’ green chloroplasts sometimes showed the greatest similarities when related species grew in the same area. Scientists have now discovered that a transfer of entire chloroplasts, or at least their genomes, can occur in contact zones between plants. Inter-species crossing is not necessary. The new chloroplast genome can even be handed down to the next generation and, thereby, give a plant with new traits. These findings are of great importance to the understanding of evolution as well as the breeding of new plant varieties.