Genetic Variation for Phenotypically Invariant Traits Detected in Teosinte: Implications for the Evolution of Novel Forms

Corresponding author: John Doebley, Madison, WI 53705., jdoebley{at}facstaff.wisc.edu (E-mail)

Communicating editor: J. A. BIRCHLER

How new discrete states of morphological traits evolve is poorly understood. One possibility is that single-gene changes underlie the evolution of new discrete character states and that evolution is dependent on the occurrence of new single-gene mutations. Another possibility is that multiple-gene changes are required to elevate an individual or population above a threshold required to produce the new character state. A prediction of the latter model is that genetic variation for the traits should exist in natural populations in the absence of phenotypic variation. To test this idea, we studied traits that are phenotypically invariant within teosinte and for which teosinte is discretely different from its near relative, maize. By employing a QTL mapping strategy to analyze the progeny of a testcross between an F₁ of two teosintes and a maize inbred line, we identified cryptic genetic variation in teosinte for traits that are invariant in teosinte. We argue that such cryptic genetic variation can contribute to the evolution of novelty when reconfigured to exceed the threshold necessary for phenotypic expression or by acting to modify or stabilize the effects of major mutations.

This article has been cited by other articles:

				G. S. Johal, P. Balint-Kurti, and C. F. Weil Mining and Harnessing Natural Variation: A Little MAGIC Crop Sci., November 1, 2008; 48(6): 2066 - 2073. [Abstract] [Full Text] [PDF]

				N. Lauter, M. J. Moscou, J. Habiger, and S. P. Moose Quantitative Genetic Dissection of Shoot Architecture Traits in Maize: Towards a Functional Genomics Approach The Plant Genome, November 1, 2008; 1(2): 99 - 110. [Abstract] [Full Text] [PDF]

				B. Liu, T. Fujita, Z.-H. Yan, S. Sakamoto, D. Xu, and J. Abe QTL Mapping of Domestication-related Traits in Soybean (Glycine max) Ann. Bot., October 1, 2007; 100(5): 1027 - 1038. [Abstract] [Full Text] [PDF]

				E. P. Kirk, C. Hyun, P. C. Thomson, D. Lai, M. L. Castro, C. Biben, M. F. Buckley, I. C.A. Martin, C. Moran, and R. P. Harvey Quantitative Trait Loci Modifying Cardiac Atrial Septal Morphology and Risk of Patent Foramen Ovale in the Mouse Circ. Res., March 17, 2006; 98(5): 651 - 658. [Abstract] [Full Text] [PDF]

				T. F. C. Mackay, R. F. Lyman, and F. Lawrence Polygenic Mutation in Drosophila melanogaster: Mapping Spontaneous Mutations Affecting Sensory Bristle Number Genetics, August 1, 2005; 170(4): 1723 - 1735. [Abstract] [Full Text] [PDF]

				N. de Leon, J. G. Coors, and S. M. Kaeppler Genetic Control of Prolificacy and Related Traits in the Golden Glow Maize Population: II. Genotypic Analysis Crop Sci., May 27, 2005; 45(4): 1370 - 1378. [Abstract] [Full Text] [PDF]

				A. V Badyaev Stress-induced variation in evolution: from behavioural plasticity to genetic assimilation Proc R Soc B, May 7, 2005; 272(1566): 877 - 886. [Abstract] [Full Text] [PDF]

				S. I. Wright and B. S. Gaut Molecular Population Genetics and the Search for Adaptive Evolution in Plants Mol. Biol. Evol., March 1, 2005; 22(3): 506 - 519. [Abstract] [Full Text] [PDF]

				J. Hermisson and G. P. Wagner The Population Genetic Theory of Hidden Variation and Genetic Robustness Genetics, December 1, 2004; 168(4): 2271 - 2284. [Abstract] [Full Text] [PDF]

				K. Saitoh, K. Onishi, I. Mikami, K. Thidar, and Y. Sano Allelic Diversification at the C (OsC1) Locus of Wild and Cultivated Rice: Nucleotide Changes Associated With Phenotypes Genetics, October 1, 2004; 168(2): 997 - 1007. [Abstract] [Full Text] [PDF]

				N. Lauter, C. Gustus, A. Westerbergh, and J. Doebley The Inheritance and Evolution of Leaf Pigmentation and Pubescence in Teosinte Genetics, August 1, 2004; 167(4): 1949 - 1959. [Abstract] [Full Text] [PDF]

				A. R. Orr and M. D. Sundberg Inflorescence development in a new teosinte: Zea nicaraguensis (Poaceae) Am. J. Botany, February 1, 2004; 91(2): 165 - 173. [Abstract] [Full Text] [PDF]

				I. M. L. Somorjai, R. G. Danzmann, and M. M. Ferguson Distribution of Temperature Tolerance Quantitative Trait Loci in Arctic Charr (Salvelinus alpinus) and Inferred Homologies in Rainbow Trout (Oncorhynchus mykiss) Genetics, November 1, 2003; 165(3): 1443 - 1456. [Abstract] [Full Text] [PDF]

				T. Ohta Inaugural Article: Near-neutrality in evolution of genes and gene regulation PNAS, December 10, 2002; 99(25): 16134 - 16137. [Abstract] [Full Text] [PDF]