A high-resolution genetic variation map covering the genomes of maize (Zea mays) and its wild relatives is reported in Nature Genetics this week, representing a new resource for breeding and improvement efforts around the scientifically and economically important crop plant. Despite maize's long history of use and refinement, little is known about the extent and potential utility of the genetic variation found in its wild relatives, which are collectively known as teosintes. In the study, a team led by scientists from Huazhong Agricultural University characterized a high-density genomic variation map from 744 genomes encompassing maize and all wild taxa of the genus Zea, identifying more than 70 million single-nucleotide polymorphisms. The researchers uncovered candidate genes involved in adaptation across both long and short time scales as well as evidence of convergent adaptation of highland teosintes and high-latitude maize, highlighting how studying variation in wild relatives can reveal genes important in crops. The findings, which have been integrated into the online ZEAMAP database, "provide a foundation for the use of crop wild relative resources for breeding in the face of increasing human populations and decreasing farmland," the authors write.