Analysis of the maize genome, indicates that its domestication resulted in a population bottleneck, resulting in loss of genetic diversity, and also artificial selection on several genes, apparently due to the action of humans.
Science, Vol 308, Issue 5726, 1310-1314 , 27 May 2005
The Effects of Artificial Selection on the Maize Genome
Stephen I. Wright et al.
Domestication promotes rapid phenotypic evolution through artificial selection. We investigated the genetic history by which the wild grass teosinte (Zea mays ssp. parviglumis) was domesticated into modern maize (Z. mays ssp. mays). Analysis of single-nucleotide polymorphisms in 774 genes indicates that 2 to 4% of these genes experienced artificial selection. The remaining genes retain evidence of a population bottleneck associated with domestication. Candidate selected genes with putative function in plant growth are clustered near quantitative trait loci that contribute to phenotypic differences between maize and teosinte. If we assume that our sample of genes is representative, ~1200 genes throughout the maize genome have been affected by artificial selection.