Heterosis is commonly observed in hybrid individuals exhibiting vigor greater either parent. Interactions between the effects of heterosis and polyploidy have been described and indicate that heterosis is stronger in polyploid individuals. However, neither the molecular basis of heterosis in diploids nor the mechanisms leading to the observed interaction with ploidy level are understood at the moment. Several genetic models exist which suggest that heterosis is due to either dominance complementation of deleterious recessives or allelic interactions and overdominance. However, these models have remained unchanged for almost a century, and the available data cannot distinguish them clearly. Tools are now available to investigate heterosis and polyploidy effects on genome-wide expression levels, to test the genetic models, and to formulate a model for the underlying molecular mechanisms. Focusing mainly on the use of microarrays and gene expression analysis in Zea mays, the proposed experiments will allow us collect the necessary data to develop a molecular model for heterosis. The results will be of great significance for agriculture because of the impact of heterosis on yield, and also forevolutionary biology as polyploidy and heterosis are important factors in the evolutionary history of many species.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32GM069141-02
Application #
6780876
Study Section
Special Emphasis Panel (ZRG1-F08 (20))
Program Officer
Tompkins, Laurie
Project Start
2003-08-01
Project End
2006-07-31
Budget Start
2004-08-01
Budget End
2005-07-31
Support Year
2
Fiscal Year
2004
Total Cost
$42,976
Indirect Cost
Name
University of Missouri-Columbia
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
153890272
City
Columbia
State
MO
Country
United States
Zip Code
65211
Lamb, Jonathan C; Riddle, Nicole C; Cheng, Ya-Ming et al. (2007) Localization and transcription of a retrotransposon-derived element on the maize B chromosome. Chromosome Res 15:383-98