For centuries, humankind has made improvements to crop plants through selective breeding and hybridization, the controlled pollination of plants. Plant technology is an extension of this traditional plant breeding with one important difference, plant biotechnology allows for the transfer of a greater variety of genetic information in a more precise controlled manner. Since introduction of plant biotechnology, many farmers have planted millions of acres of biotech corn, cotton, soybeans, fruit, and other crops. While these new varieties have enhanced, crop protection reduced production costs and increased yields, raising concern among some consumers, legislators, and activists.
Many critics of agricultural biotechnology have often been dismissed. Sywanen, a professor of medical microbiology, defends the concerns of biotechnology opponents in his article titled, "In search of a horizontal gene transfer". The impact of horizontal gene transfer concerns agricultural biotechnology critics who claim that genes inserted into domesticated organisms might be transferred to wild organisms, an example would be the transfer of antibiotic resistance marker genes to soil bacteria. Sywane's studies of bacterial and plant phylogeny indicate horizontal gene transfer is involved in evolutionary change. A disturbing consequence of horizontal gene transfer in bacteria is the potential for antibiotic resistance, and other traits carried on plasmids to migrate from one type of bacterium to another. There has been evidence suggesting that genomic DNA is transmitted in nature. In bacteria, conjugation is the most likely mechanism responsible for gene transfer. Another research stated that transposon-like elements are likely vehicles for cutting and pasting genomic DNA from one organism to another, and that viruses may be responsible for transmitting genes between eukaryotes. Sywanen argues that some of the gene frequency studies provide weak evidence of the dangers of gene transfer because the gene was already present, so it is far from clear that its presence in genetically engineered plants will add significantly to the existing danger.