A Close Look At The GMO Breeding Process
May 6, 2016 To many in the general public, genetic engineering is still a highly misunderstood technology. With all of the resources available to educate the public on the breeding process, there is still much uncertainty about what genetic modification is, and what’s required to bring a GMO crop to market.
Surinder Chopra, professor of Maize Genetics at Penn State University, answers a few questions about the breeding process in detail, discussing safety concerns, marker-assisted selection, the future of the biotech industry, and more.
What are the traditional plant breeding techniques typically used?
Chopra: Breeding techniques include conventional breeding and forward and reverse genetics.
Conventional plant breeding is a traditional method of crop improvement in which a plant breeder selects traits of interest and incorporates these traits by crossing two parental lines. One of the parental lines has the new trait of interest, and the other line carries all other desirable traits but lacks this new trait.
Forward genetics identifies genes responsible for a specific phenotype, which can be a plant trait such as growth, resistance, yield, etc. Reverse genetics analyzes the phenotype after a known gene is disrupted.
Has marker-assisted selection (MAS) improved the plant breeding process?
Chopra: Simple traits that are controlled by single genes can be mapped with relative ease by the use of molecular markers through backcross breeding. However, complex traits or quantitative traits are controlled by more than one gene and are thus mapped as quantitative traits locus (QTL). Using the DNA-gel-blot-based methods, restriction fragment length polymorphic (RFLP) markers have been used previously in maize, sorghum, and barley to identify QTLs conferring tolerance to drought and diseases.
In addition to gene and QTL mapping, molecular markers are used in association mapping studies at the single-candidate gene level. There are several examples of associations of candidate genes and QTL with given traits. With the advancement in DNA sequencing technologies, genetic information can be readily generated from millions of molecular markers obtained from next generation genome sequencing platforms.
What are the main differences between genetic engineering and other traditional plant breeding techniques?
Chopra: Genetic engineering targets a specific trait and this introduces a single gene which controls that trait.
Traditional plant breeding deals with developing segregating populations, and from there selecting a desirable trait, which is a very time-intensive process. Traditional plant breeding also introduces genetic drag because of the unwanted traits which must be removed by several backcrosses.
Genetic engineering does use several steps of traditional plant breeding, but the knowledge of the introduced gene makes the process of selection faster.
What are some of the concerns with genetic engineering?
Chopra: There is a general concern with unwanted gene products that either are new to the human food chain and/or are not well researched scientifically for potentially negative effects to the human body.
Many of the issues are also centered on the effects of new plants to the non-targeted insect species, especially in the case of insect-tolerant GE crops. There is also the concern of monoculture crops and the loss of genetic diversity because of commercialization of fewer transgenic crops. In addition, there are concerns of patents and rights by seed companies that do not allow growers to save their own seeds of the commercialized crop.
What are some of the latest biotech developments and trends in the specialty crop market?
Chopra: Current developments include disease, virus and pest tolerance, ripening, flavor, food safety, and storage.
Where do you see the biotech industry headed in the near future? Do you think consumer acceptance will eventually evolve to embrace biotechnology?
Chopra: The future biotech industry is very sensitive to the consumer’s concerns and is constantly developing ways to address these concerns. Based on discussions with scientists from the seed industry, they are trying different scientific methods to focus their efforts on genetic engineering and modern breeding in which there are no unwanted selectable markers left in the final product. They’re also focusing efforts on understanding the changing environment and developing designer crops for such climatic conditions like drought and cold tolerance by the use of genetic engineering.
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