Submitted to: Proceedings of the National Academy of Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2013
Publication Date: 4/25/2013
Citation: Nguyen, P., Sykorova, M., Sichova, J., Kuta, V., Dalikova, M., Capkova-Frydrychova, R., Neven, L.G., Sahara, K., Marec, F. 2013. Neo-sex chromosomes and adaptive potential in tortricid pests. Proceedings of the National Academy of Sciences. 10:6931-6936. Interpretive Summary: Codling moth is a major pest of apples in the United States and Europe. Scientists from the USDA-ARS, Wapato, WA, the Czech Republic, and Japan mapped the Z-sex chromosome of codling moth. They found that the Z-chromosome arose from the fusion of the ancestral Z-chromosome with an autosome corresponding to chromosome 15 in the Bombyx mori, the silk moth, reference genome. This fusion brought several detoxification and pesticide resistance genes into the Z-sex chromosome. The authors suggest that the fusion significantly increased the adaptive potential of tortricid moths and thus contributed to their evolutionary diversification and subsequent species seperation. This research contributes to the management of codling moth and other tortricid pests and provides a new perspective concerning potential roles of neo-sex chromosomes in the adaptive radiation of phytophagous insects, a huge group of the class Insecta.
Technical Abstract: Changes in genome architecture often have a significant effect on ecological specialization and speciation. This effect may be further enhanced by involvement of sex chromosomes playing a disproportionate role in reproductive isolation. We have physically mapped the Z chromosome of the major pome fruit pest, the codling moth, Cydia pomonella (Tortricidae), and show that it has arisen by fusion between an ancestral Z chromosome and an autosome corresponding to chromosome 15 in the Bombyx mori reference genome. We further show that the fusion originated in a common ancestor of the main tortricid subfamilies, Olethreutinae and Tortricinae, comprising almost 700 pest species worldwide. The Z-autosome fusion has brought two major genes conferring insecticide resistance and the whole set of detoxification genes under sex-linked inheritance. We suggest that the fusion significantly increased the adaptive potential of tortricid moths and thus contributed to their radiation and subsequent speciation.