NCCC_OLD204: The Interface of Molecular and Quantitative Genetics in Plant and Animal Breeding
Statement of Issues and Justification
Population and quantitative genetics have had remarkable success in both plant and animal breeding. Those advancements, however, were limited by the relatively simplistic assumptions of the models used for inheritance of quantitative traits and the tools available for estimating genetic worth. With the advent of molecular genetics, those limitations no longer need apply. We now have the means to uncover the true modes of inheritance of quantitative traits by unlocking the mysteries of the genetic code. Although structural genomics has revealed the DNA sequence of the human genome, less than 1% of the human genetic code can be deciphered into functional genes. The DNA sequence is like the Egyptian hieroglyphics on the Rosetta stone. We have the cipher but we do not yet know what it all means. Functional genomics is the painstaking process of extracting meaning from the code. Functional genomics will reveal gene function and regulation, knowledge that we can apply in advanced breeding programs of agriculturally important species. The genomics revolution also has profound importance for management of natural populations to determine breeding structures, rate of inbreeding, and effective population size.Several obstacles, however, remain before such a goal can be realized. Those are detailed in the next section.
Issues that must be addressed for implementation of genomics in plant and animal breeding programs include: 1. What are the optimum strategies to map genes for quantitative traits, so-called quantitative trait loci or QTL, in outbred populations, with and without pedigrees, such as those used in tree breeding? 2. What is the optimum method of incorporating such genomic information into breeding programs to enhance rates of genetic improvement? 3. How much additional improvement can a breeder expect to make by including such information in breeding programs and at what cost? 4. What types of traits benefit most by including molecular information in selection programs? 5. How can genomic information from completely sequenced model organisms (fruit fly, human, mouse, zebrafish, and arabadopsis) be used to infer gene structure, regulation and function in agriculturally or ecologically important species, whose genomes may never be completely sequenced? 6. How can genomic information be incorporated into quantitative genetic models to better reflect the underlying biology?
The issues and questions detailed above are best addressed by scientists working in diverse fields of genetics, from gene mapping to bioinformatics, and with a diverse range of species, both plant and animal.
On a national basis, the NRSP8 National Animal Genome Project and the Plant and Animal Genome projects of the USDA/NRI and NSF have provided information on sequence data and structural genomics of domesticated plants and animals. The USDA recently reduced funding for the Plant and Animal Genome program areas of the USDA/NRI. Due to this and other budget constraints, animal genome projects rely on information provided by the human genome project that was completed jointly by the NIH and the private sector. Like the animal genome projects, plant genome projects are depending on a few well-funded efforts, primarily the arabadopsis and rice genome projects, to provide the basis for deciphering other plant genomes.
Concentrating resources on the complete genetic characterization of a few representative genomes results in a wealth of information that saves us the trouble of completely sequencing every species on earth.
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