What is Molecular Assisted Breeding Technology?

Expert response from Community Manager

Thursday, 12/02/2015 13:39

Thank you for your question, which is one of the most important questions that should be asked by someone who wants to understand GMOs. On the surface this seems like a straightforward question that can be answered easily by extracting three definitions from a glossary of key terms.  However, quick and easy answers will not provide enough information for understanding the scientific basis of these technologies, which is the shared objective of the scientists who answer questions submitted to GMO Answers.

Infographic from Nature.com.

The most useful thing that I can do to help you truly understand these technologies is to explain the terms, or concepts, in a way that allows you to place them in a historical context.  This exercise is easy for the term “biotechnology” (let’s put aside “agri” for now).  If you break biotechnology into its roots, bio and technology, then a reasonable definition would be:

Biotechnology – using living things to do something useful or practical, such as making a product or solving a problem.

When you read that definition, I hope you are struck by the realization that biotechnology, defined in this way, is as old as the human species.  Living things have always provided products, such as food and clothing, and have solved problems like preserving foods. 

Over time, as humans used living things to provide life’s necessities and solve problems, our ancestors began changing them to serve our needs more effectively. The most obvious example is the domestication process: wild plants and animals were converted into the crops we grow and livestock we keep by changing their genetic makeup. 

Using living things for practical ends, i.e., biotechnology, is inextricably linked to changing them through genetic modification to accentuate traits that better meet the practical goal and eliminate traits that don’t.  This pattern of using and genetically changing organisms persists well beyond domestication of plants and animals to all of living things we use to solve problems and make products, e.g., yeast that create fermented foods, such as bread and wine; plants, molds and bacteria that naturally produce antibiotics and other pharmaceuticals; microbes that breakdown waste products and pollutants; viruses that are the basis of vaccines; plants and bacteria that produce food additives, such as vitamins, amino acids, pectin and citric acid.   

If the terms “biotechnology” and “genetically modified organism” apply to every organism used in agriculture, pharmaceutical manufacturing, food processing, environmental remediation and other industrial sectors, then why are “biotechnology” and “genetic modification” discussed as if they were brand new?  During the 1960s and 70s, knowledge of the biological sciences reached a point where we could understand living organisms at their most basic level - cells and molecules.  This understanding, in turn, has allowed us to use cells and biological molecules, rather than the whole living organism, to achieve certain goals, leading to this definition:

Modern Biotechnology - using the cells and molecules from living things to do something useful or practical, such as making a product or solving a problem.

In truth, humans have always used and changed the cells and molecules of living things to achieve the practical goals described above – provide food and clothing; preserve food through fermentation; breakdown waste products, etc. - but for many centuries we did not know we were exploiting cells and manipulating molecules.  Our lack of understanding of the cellular processes and molecular functions we were using and changing meant that our uses and manipulations of living things were trial and error ventures, informed by experience but not grounded in scientific understanding.  Over time, as science provided insights into the inner workings of organisms, our proficiency at using and changing living things improved.  Now that we understand cellular processes at their most basic level—the molecular level—we are able to predict the effect of a manipulation more precisely and direct the change we want to effect with greater specificity.

Here’s another way to define modern biotechnology:

Biotechnology is a collection of tools, based on cells and biological molecules, used by many industrial sectors to make new products, improve existing products and processes, identify problems, and conduct research. The modern biotechnologies include techniques such as genetic engineering, monoclonal antibody technology, cloning technology, cell culture, bioprocessing technology and bioinformatics technology.

So the tools of biotechnology allow us to do things and understand things.  Some of the things we are doing with biotechnology are things we have done before, but modern biotechnology allows us to do it better.  For example, doctors have treated Type 1 diabetes with insulin injections for almost 100 years.  Before modern biotechnology the protein insulin was extracted from the pancreatic tissue of animals (“old biotechnology”), but now the injected insulin is made by either genetically engineered (GE) bacteria or GE yeast and is identical to human insulin, thus enhancing its effectiveness and lessening the possibility of allergic reactions to a foreign proteins. 

Now….. to answer your question!

The list of modern biotechnological tools above – and others - are used in production agriculture, so the term “agribiotechnology” is much broader than genetic modification.  

Each of the tools of modern biotechnology above also has a historical continuum of “old biotechnologies” that led to today’s modern biotechnology that relies on using living cells and biological molecules in more predictable and precise ways.   This sort of historical continuum of technology development to achieve a specific, practical goal is best exemplified by the modern biotechnology, genetic engineering.

Genetic engineering is but one of many techniques that have been used to change the genetic makeup of all the living things we use – plant, animal or microbe.  Consistent with the explanation above, for thousands of years our ancestors changed the genetic makeup of plants and animals without understanding the biological basis of their manipulations. They knew nothing about reproduction or genetics, but experience had taught them that offspring often resemble their parents. This minimal understanding enabled the use of artificial selection, which led to the major genetic changes that converted wild plants and animals into crops, livestock and companion animals. 

Once more was understood about reproduction and genetics, breeders began to select certain individuals with desirable traits for cross-breeding.  With respect to crops, this form of genetic modification through selective breeding originally was restricted to members of the same crop species, but gradually, as science revealed ways to circumvent natural barriers to reproduction, plant breeders began to cross plants that would never be able to breed in nature. They first crossed plants in different species in the 1700s; by the late 1800s they had developed lab techniques that allowed them to move genes between plants in different genera, the next level of taxonomic, or genetic, difference beyond species. By the 1970s plant scientists had developed techniques for combining the genetic material from plants even more distantly related, i.e., plants in different families.  Genetic engineering represents the next step in the continuum of genetic modification of crops, and it eliminates all taxonomic barriers to gene transfer. Genes found in bacteria can now be moved into crops to achieve certain, practical goals.  A good description of the history of genetic modification can be found here.

Another difference in genetic modification through genetic engineering versus selective breeding is the number of genes that are transferred into the crop plant. With genetic engineering, single genes for new desirable traits are given to crops.  With selective breeding, tens of thousands of genes are moved into the crop. So, genetic modification through genetic engineering is more precise than genetic modification through breeding.

Irrespective of the differences in the techniques that lead to genetic modification, the goals are the same:  the accumulation of desirable traits in crop plants. In breeding, half of the genetic material in each parent is found in the offspring plant, and this half may or may not contain the gene responsible for the new trait the breeder hopes to add to the crop’s valuable traits.   Before modern biotechnology, breeders needed to plant the offspring seed and wait months – often to maturity - to see if the offspring had inherited the gene for the new trait.  Now, the research tools of biotechnology allow breeders to look directly at the genetic information in a plant, so they no longer need to grow out the offspring plant and wait to see if it has the new gene.  Instead they can chip off a small piece of the seed and use molecular techniques to see if the offspring has the new gene.  Sometimes breeders know enough about the gene to look specifically for that gene.  Other times, they have identified a marker, which is genetic information that is always inherited with the new trait. So marker assisted breeding is simply well-informed, efficient breeding.  Having that marker eliminates some of the trial and error of traditional breeding and also cuts months from the product development timeline.  

By the way, the molecular techniques that are used in marker assisted breeding are the very same techniques that have allowed researchers to identify genes associated with inherited diseases, like cystic fibrosis.