World Traveller: Genomics, Climate, and Geographic Diversity of Three Brachypodium Species

Introduction of novel species into non-native environments can have biodiversity and agricultural effects costing billions of dollars in damage yearly. The likelihood of introduced species becoming invasive isn't always clear, nor are the effects of introduction events immediately apparent. A total of 1,818 samples from 817 global locations were genotyped for species classification by genomic signatures and to assess the genomic variation of three Brachypodium distachyon complex species. Using two reference genomes, species classification was achieved to find 476 candidate B. distachyon, 60 B. stacei, and 1,190 B. hybridum. B. distachyon was found to have 125 unique genotype groups, B. stacei had eight, and B. hybridum had 80 genotype groups. Geographic distribution was also modelled using R and MaxEnt software to calculate sensitive locations to invasion of each species. Using custom scrips in R, surface area of was calculated for each species and B. hybridum was found to have the highest global surface area deemed habitable at 2,770,680 km² outside the native range. Within B. hybridum many genotypes were found in multiple locations, but genotype NRD-1 was found in the most locations and on multiple continents. The climate diversity of each species was also calculated and within genotype groups. B. hybridum was found to be the most widespread species with significant genetic diversity in native, but also non-native locations indicating many introduction events in North America and Australia. In particular, NRD-1 was also the most climate diverse group and deemed the most widely adapted and wide spread genotype of the Brachypodium distachyon complex species.