Ecosystem diversity, the diversity of a place at the level of ecosystems. Crop diversity, the variance in genetic and phenotypic characteristics of plants used in agriculture. Functional diversity (ecology), the elements of biodiversity that influence how ecosystems function; see diversity-function debate.
Gene therapy is the therapeutic delivery of nucleic acid polymers into a patient's cells as a drug to treat disease. Until September 1990, it had never been successfully done, and it is still an experimental and emerging medical technology.
Gene therapy utilizes the delivery of DNA into cells, which can be accomplished by several methods, summarized below. The two major classes of methods are those that use recombinant viruses (sometimes called biological nanoparticles or viral vectors) and those that use naked DNA or DNA complexes (non-viral methods).