| Abstract Detail
Thursday Afternoon Breeding and Variation Doebley, John [1]. The molecular genetics of domestication: an example from maize. MAIZE is a domesticated form of a wild Mexican grass called teosinte. The domestication of maize from teosinte occurred about 8,000 years ago. As a result of human (artificial) selection during the domestication process, dramatic changes in morphology arose such that maize no longer closely resembles its teosinte ancestor in ear and plant architecture. Quantitative trait locus (QTL) mapping has shown that many genes contributed to the differences between maize and teosinte, but among these are several of very large effect. We have cloned and analyzed two of these large-effect genes. teosinte branched (tb1) is largely responsible for the difference between the long branches of teosinte versus the short branches of maize. tb1 encodes a transcriptional regulator that functions as a repressor of branch elongation. Gene expression analysis indicates that the product of the teosinte allele of tb1 accumulates at about half the level of the maize allele. Fine-mapping experiments show that the differences in phenotype and gene expression are controlled by an enhancer that is 65 kb upstream of the ORF. teosinte glume architecture (tga1) is largely responsible for the formation of a casing that surrounds teosinte seeds but is lacking in maize. tga1 also encodes a transcriptional regulator, however in this case a single amino acid change appears to represent the functional difference between maize and teosinte. Overall, our work and that of other lab groups are beginning to reveal the nature of the genetic and developmental changes underlying the maize domestication.
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1 - University of Wisconsin, Genetics, 425-G Henry Mall, Madison, WI, 53706, USA
Keywords:
Domestication
maize.
Session: SOL07-5
Location: Ballroom AB/Monona Terrace
Date: Thursday, July 27th, 2006
Time: 4:00 PM
Abstract ID:371 |
