Genetic analysis of the morphological differences between maize and teosinte.

Area of Science:

• Plant genetics
• Evolutionary biology
• Molecular genetics

Background:

• Maize (Zea mays ssp. mays) and teosinte (Z. mays ssp. mexicana) exhibit significant morphological differences, particularly in inflorescence traits.
• Understanding the genetic underpinnings of these differences is crucial for studying plant evolution and crop domestication.

Purpose of the Study:

• To identify and characterize the molecular loci controlling morphological variation between maize and teosinte.
• To elucidate the mode of inheritance for key inflorescence traits and assess the effects of identified loci.

Main Methods:

• Utilized molecular marker loci for genetic analysis.
• Employed regression and interval mapping techniques to analyze trait inheritance.
• Investigated the distribution and magnitude of genetic effects across the genome.

Main Results:

• Congruent results from regression and interval mapping regarding the number and effect sizes of loci, with interval mapping yielding larger estimates.
• Inflorescence trait variation is primarily controlled by one or two major effect loci, supplemented by several minor effect loci.
• Five genomic regions, including the known teosinte branched1 (tb1) gene region, explain most of the morphological variation between maize and teosinte, suggesting pleiotropy.

Conclusions:

• The dramatic morphological divergence between maize and teosinte is attributable to a limited number of genomic regions with substantial effects.
• The findings support a model of inheritance involving major and minor effect loci for most traits.
• This study provides insights into the genetic architecture underlying plant morphological evolution.