Fig. 3.

Population relationships and genome size characteristics. (A) Admixture graph with a good fit to the genomic data, showing El Gigante maize as an early branch of the Pan-American cluster carrying excess parviglumis ancestry. South American members of the Pan-American population carry excess ancestry from earlier-dispersed South American lineages, revealing hybridization in South America. (B) f₄-statistics showing that all individual Pan-American genomes and the El Gigante maize carry excess parviglumis ancestry compared with South American and North American lineages. Errors bars at 1 and 3 SEs computed using a block jackknife in 5-Mb blocks. (C) Proportion of characteristic South American lineage alleles at AIMs among geographically southern (samples physically originating in South America) and northern (originating in North and Central America) maize genomes, showing that El Gigante maize is the most South American-like of northern maize. (D) 180 bp heterochromatic knob frequency (RPKM) as a proxy for genome size, compared with distance from the domestication center. The two regression lines show 1) the correlation between distance and genome size in all samples—a general trend to genome contraction with distance—and 2) the reverse trend in samples with ≥90% Pan-American ancestry.