Gene Discovery, Ownership and Access for Developing Countries in the Era of Molecular Genetics|
Genetic variability fuels crop improvement and has sustained crop evolution and adaptation for thousands of years. It is a vital resource for humanity's future survival given that increases in crop production will most likely come from higher yields per unit area rather than from new crop lands. Intensive plant breeding using scientific methods during much of the 20th century has led to significant gains in productivity for most major world crops. However, the cost of these achievements has been narrower genetic variability within the elite gene pool, increased genetic uniformity and vulnerability in crops, and erosion of native genetic resources (Lee, 1998). The consequences of narrow genetic pools have been disastrous in the past. Examples abound: the infamous Irish famine of 1850 caused by a genetically uniform potato crop susceptible to blight; the famine triggered in India in 1943 by the brown spot disease of rice. More recently the Southern corn blight that struck the United States corn industry in 1970 caused over a billion dollars worth of damage (Horsfall, 1972). Future consequences will be harsh unless steps are taken to reverse the dangerous trend in genetic erosion of our main sources of food. Furthermore, it is suspected that reduced genetic variability in most major crops is responsible for the decrease in genetic gain for yield (Lee, 1998). Among the important causes for this narrow genetic base is that crop species have undergone genetic bottlenecks during the domestication and breeding processes (Tanksley and McCouch, 1997). In the past it has been difficult to use exotic germplasm because useful genes are often linked to genes controlling undesirable traits and there were no tools to go after specific genes or genomic regions. The development of densely populated genetic linkage maps, marker assisted selection, expressed sequence tags, chromosome walking and gene cloning, have changed the scenario and it is now possible to transfer specific genes or loci to cultivated plants. In developed countries, like the United States, major efforts are underway to use these tools to mine, capture and transfer useful genes from exotic germplasm to crop plants (Tanskely and Nelson, 1996; Tanksley and McCouch, 1997). Also the completion of the Arabidopsis genome sequencing project will result in a number of new techniques (Sommerville and Dangi, 2000) that will enhance our understanding of genomes and, therefore, our ability to exploit exotic genetic resources. Not surprisingly increased research and gene discovery will correspondingly increase the value of exotic germplasm, meaning land races and wild ancestors of cultivated plants.