chromosomal regions. Many miRNA genes involved in regulation of plant development have been found to be quite conserved between plants studied. Domestication of plants such as maize, rice, barley, wheat etc. has also been a significant driving force in their evolution. Some studies have looked at the origins of the maize plant and found that maize is a domesticated derivative of a wild plant from Mexico called teosinte. Teosinte belongs to the genus Zea, just as maize, but bears very small inflorescence, 5–10 hard cobs, and a highly branched and spread-out stem. Crosses between a particular teosinte variety and maize yield fertile offspring that are intermediate in phenotype between maize and teosinte. QTL analysis has also revealed some loci that when mutated in maize yield a teosinte-like stem or teosinte-like cobs. Molecular clock analysis of these genes estimates their origins to some 9000 years ago, well in accordance with other records of maize domestication. It is believed that a small group of farmers must have selected some maize-like natural mutant of teosinte some 9000 years ago in Mexico, and subjected it to continuous selection to yield the maize plant as known today. Another case is that of cauliflower. The edible cauliflower is a domesticated version of the wild plant Brassica oleracea, which does not possess the dense undifferentiated inflorescence, called the curd, that cauliflower possesses. Cauliflower possesses a single mutation in a gene called CAL, controlling meristem differentiation into inflorescence. This causes the cells at the floral meristem to gain an undifferentiated identity, and instead of growing into a flower, they grow into a lump of undifferentiated cells. This mutation has been selected through domestication at least since the Greek empire. See also Evolutionary developmental biology Plant morphology Comparative phylogenetics Plant evolution Evolutionary history of plants References Further reading The Genetics of plant morphological evolution Plant evolution and development in a post-genomic context Evolution of leaf developmental mechanisms Developmental genetics and plant evolution Evolutionary Developmental Biology Evolutionary biology Evolution of plants