In Science: Ancient maize adaptation to temperate climate

Genomic estimation of complex traits reveals ancient maize adaptation to temperate North America

Swarts, K., Gutaker, R. M., Benz, B., Blake, M., Bukowski, R., Holland, J., Kruse-Peeples, M., Lepak, N., Prim, L., Romay, M. C., Ross-Ibarra, J., Sanchez-Gonzalez, J. d. J., Schmidt, C., Schuenemann, V. J., Krause, J., Matson, R. G., Weigel, D., Buckler, E. S., Burbano, H. A. (2017)

People introduced maize to the southwestern US by 4,000 years ago; full agriculture was established quickly in the lowland deserts but delayed in the temperate uplands for 2,000 years. We test if the earliest upland maize was adapted for early flowering, a characteristic of modern temperate maize. We sequenced fifteen 1,900-year old maize cobs from Turkey Pen Shelter in the temperate Southwest. Indirectly validated genomic models predicted that Turkey Pen maize was marginally adapted with respect to flowering, as well as short, tillering and segregating for yellow kernel color. Temperate adaptation drove modern population differentiation and was selected in situ from ancient standing variation. Validated prediction of polygenic traits improves our understanding of ancient phenotypes and the dynamics of environmental adaption.