Methods and genetic compositions to limit outcrossing and...

Multicellular living organisms and unmodified parts thereof and – Method of introducing a polynucleotide molecule into or... – Nonplant protein is expressed from the polynucleotide

Reexamination Certificate

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C800S260000, C800S271000, C800S278000, C800S287000, C800S294000

Reexamination Certificate

active

06753460

ABSTRACT:

BACKGROUND OF THE INVENTION
The increasing number and diversity of plants containing novel traits derived from recombinant DNA research present both environmental and commercial concerns. The concerns arise from the potential for novel traits to spread by pollen to sexually compatible plants in a natural or cultivated population.
Plants with new and altered traits imparted by genetic technologies and recombinant DNA technology in particular are now viewed as the cornerstone of the crop biotechnology industry. Currently a considerable number of crops plants with novel traits that originated from tissue culture, somatoclonal variation or mutation as well as genetic engineering are undergoing field trials and the first stages of commercial release. These plants not only include conventional crops grown on an annual basis, but other plants such as trees or shrubs which comprise novel traits and are perennial in nature.
Modern crop varieties comprise both individual genes that confer a particular trait and combination of genes assembled through conventional plant breeding. Accordingly, as more novel traits are developed and incorporated into modern crop varieties, it is valuable to have a means to preserve genetic compositions, including those of specific crop varieties, cultivars or breeding lines. Of particular value is the preservation of crops which carry traits not usually found in the crop; for example, plants which produce novel oil, meal or other components or those plants modified to produce speciality chemicals. Additionally, perennial plants such as trees are being produced which carry novel traits such as altered lignin levels, insect and fungal resistance and herbicide tolerance.
Novel traits are introduced into plants by conventional breeding or genetic engineering. However, to date neither route provides features that can be routinely used for maintaining germplasm purity, or controlling persistence or potential spread of the novel trait. Current vectors and genetic compositions typically do not address two important issues: (1) commercial issues such as the prevention of transformed crop plants or elite varieties from contaminating other commercial productions, or the prevention of introgression of alien germplasm from closely related cultivars or plant species, and; (2) environmental issues such as the removal of transformed crop plants or related species that have acquired the genes in question from non-agricultural environments. Additionally current transformation methods do not provide the means for reducing the introduction of genes via pollen mediated out-crossing to other cultivars or related species (either wild or cultivated).
The single largest immediate risk for the use of many crops with novel traits is the risk of contamination among commercial productions of the same crop species. The risk of a crop species such as oilseed rape or canola (
Brassica napus
) to become a weed or to cross with wild weedy relatives is modest compared with the near certainty of crossing with other commercial productions of canola, especially where large production areas exist. In the past this has not been a significant problem for farmers and commercial processors for several reasons. First, breeding objectives have been relatively uniform for canola crop; second, only a small number of cultivars have comprised 90-100% of the total acreage grown by farmers; and third, the only speciality type, traditionally cultivated, high erucic acid industrial oil cultivars have been grown in physical isolation. Accordingly, cross contamination of food quality canola varieties with genes conferring high erucic acid has not been a serious issue.
Recently additional unique varieties have been released. These include varieties that carry recombinant genes which confer tolerance to herbicides and varieties developed by conventional breeding which have variations in fatty acid profile, such as high oleic acid. Purity of seed, both during production and harvesting of canola seed for crushing and processing is now a growing issue. Because of the impending modification of canola with numerous additional recombinant genes that impart different properties to the oil (e.g. high laurate content) or the use of plants as producers of heterologous proteins such as pharmaceuticals, potentially serious industrial cross contamination may be anticipated.
These issues extend to many crops in addition to Brassica oilseeds. In maize, increasing emphasis on herbicide tolerance, insect resistance and diversification of modified end products (eg. starch, oil, meal) clearly indicates that many different traits will be incorporated in the corn crop. As some maize varieties are destined for specialized use, such as wet milling or feed, or even production of pharmacologically important proteins, the issue of segregation of these speciality types from the mainstream is relevant. Considering that corn pollen can sometimes travel significant distances, a genetic means to control pollination is be highly advantageous.
Similarly, the proximity of perennial plants to their wild relatives is a problem. For instance, a transgenic tree expressing insect tolerance could cross with a wild species of tree to create a hybrid that expresses insect tolerance. Under managed conditions such as plantations, insect resistance would not have a significant environmental impact. However, should the insect resistance trait become widespread in a natural forest population a serious ecological problem could result. Insect populations are part of the food chain in a forest system and reduced levels of insects could lead to a collapse of the predator population, which is often native bird species. Accordingly, for unmanaged systems control of the spread of genes that may carry environmental consequences is a highly desirable goal.
Currently physical isolation combined with border rows that function as pollen traps have been employed to contain transgenic plants under study and development. This method, however, is impractical for widespread cultivation. Moreover, with increasing production and distribution of an increasing number of different transgenic types, the potential for contamination increases dramatically. This issue has recently become a major concern for the oilseed rape industry and will become a greater issue for other major crops (eg. corn) as the numbers of different recombinant and speciality genotypes reach the market place.
In addition to cross-contamination among commercial crop productions, another concern is the potential spread of crops used as vehicles for producing heterologous proteins of commercial or medicinal value. These novel protein products can potentially contaminate plants destined for food use and export. Although production standards can be implemented that will attempt to preserve the identity of individual transgenic lines and reduce unintended contaminations, the outflow of genes to other cultivars will eventually occur. The potential spread of genes that cannot be easily identified, e.g. by herbicide tolerance, nor impart a distinctive morphology has yet to be addressed by government or industry.
Methods which control the spread of transgenes into the environment or other commercial cultivars are also useful for preventing the introgression of alien germplasm into identity-preserved commercial varieties. In this regard “alien germplasm” is defined as any germplasm which does not comprise the full complement of traits of the identity-preserved cultivar. Accordingly alien germplasm can include both sexually compatible wild relatives and other commercial varieties of the crop. With an increasing number of plants carrying novel traits being contemplated for commercial production, methods that prevent the contamination of both seed production and commodity production will provide a valuable means to maintain germplasm purity and identity preservation.
As an example, many enzymes have been tested that alter plant oil production in oilseed crops such as soybean corn and canola. The same plant species have bee

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