1.07: Genetic Engineering

a genome is the full set of

DNA in an organism's cells. To better understand how organisms work—which genes they have and what those genes do—scientists have started to determine the complete sequence of DNA in several types of organisms, including humans. The field of research that has grown around the study of the whole genome is called genomics.

Bt corn is a genetically modified crop that contains a gene from another species. Which characteristic does this gene give the plant?

insect resistance

Scientists study genomes to identify genes that encode for helpful traits.

David Salt, a scientist at Purdue University, studies plants that have a unique ability to take up metals into their tissues. When absorbed in high quantities, metals kill most plants, but the plants Salt studies have the ability to take up metals and thrive. He began to think that these plants must have a gene or series of genes that allows them to do this. In a series of experiments, he identified the gene that helps certain plants tolerate the metal selenium. This metal occurs naturally in the soil in some places, but in other locations, an abundance of the metal makes soil toxic to some plant species. One of the plants that Salt studies is a little weed in the mustard family. The plant is a great choice for research because its entire genome has been sequenced. Knowing the genes allows Salt to explore new uses for this information.

In 2003, scientists completed a full sequence of the human genome.

Francis Collins, director of the Human Genome Project, oversees a team of researchers mapping all genes in humans.There are approximately 25,000 genes in the human genome. In 1990, scientists began one of the largest collaborative research projects known—building a complete sequence of the human genome. By 2003, teams of scientists released a rough draft containing the full sequence of each human chromosome. Their work continues today. This project is called the Human Genome Project,and it is opening doors to countless new research questions. With the full genome in hand, scientists are trying to determine the full set of human genes, how they are regulated, and what those genes do—that is, which protein each gene codes for.

Despite its potential benefits, many people have concerns about genetic engineering.

Genetic engineering of crops and other plants promises many benefits, but also raises some interesting questions. For example, what will prevent the spread of pollen from genetically engineered plants to other plants? This question is especially important to organic farmers, since foods that contain recombinant DNA cannot obtain organic certification from the U.S. Department of Agriculture. There are many valid questions. Can scientists predict the long-term effects that genetically modified organisms may have on natural ecosystems? Can people be allergic to new genes introduced into crops? Genetic engineering is a field with no clear definitions of what's right and what's wrong. For this reason, scientists and policy makers work together to find a balance between the benefits and concerns.

Genetic engineering is the process of manipulating the DNA of organisms to further advance biotechnology.

Genetic engineering uses recombinant DNA technology to introduce a gene from one organism into the DNA of a second organism.The protein coded for by the gene is then made by the second organism. Genetic engineering is a field with much promise in agriculture, medicine, and energy. Despite these benefits, some people are concerned about the potential implications of genetic engineering on human health and the environment.

Genetic engineering may help produce fuel from crop plants and plant waste.

Grass clippings, leaf piles in the fall, fast-growing trees, and piles of stalks and cobs left over on the fields after the corn harvest: Each represents a potential future source of ethanol. While some scientists are engineering strains of corn that can easily be converted into ethanol, others are focusing on ways to turn the whole plant into ethanol. This process is accomplished by breaking down the molecule cellulose and releasing the sugars that can be fermented into ethanol. To help, scientists are looking to some of the organisms that naturally digest cellulose—the bacteria that live in termite stomachs and fungi that break down dead wood. By identifying the genes that help these organisms break down cellulose, scientists hope to one day genetically engineer bacteria that could create ethanol from huge quantities of leftover plant material.

Genetic engineering is an active area of research in crop production.

In the introduction to this lesson, you read that that between 60 and 70 percent of processed foods contain at least one ingredient from a genetically engineered crop plant. But what are these crop plants? Why have they been genetically engineered? Corn and soybeans are the two crop species in which genetic engineering is most widespread. Much of the commercial seeds used by farmers is genetically engineered to contain genes that make the plants resist insects or herbicides sprayed on fields to control weeds. One commonly planted, genetically modified corn is Bt corn. This type of corn contains a gene from a common bacterium that lives in soil. The gene, when inserted into the corn genome, produces a protein that kills the corn borer, a type of caterpillar that is a common pest in cornfields.

Genetic engineering involves using recombinant DNA to introduce new genes to organisms.

Salt identified the gene that helps some plants tolerate selenium, and now he pictures introducing that gene to fast-growing plants.By doing this, Salt might develop a crop plant that can pull extra selenium from the soil. Removing selenium allows other plants to grow there in the future. These newly created plants will be special selenium detoxifiers—a plant army of soil cleaners. These plants are a unique example of phytoremdiation, a process by which plants are used to remove toxins from soil. To make all this work, Salt uses recombinant DNA to combine the genes of different plants. His research is just one of thousands of examples of research involving how different genes can be harnessed and used for a variety of different purposes.

Scientists have sequenced the genomes of many other organisms.

The field of genomics isn't only focused on the human genome. Scientists also have sequenced the genomes of several other model organisms.Understanding the genomes of other organisms will help scientists explore questions about relationships between organisms, compare gene regulation mechanisms, and identify genes that control various functions. Since 1995, scientists have sequenced the genomes of more than 180 organisms. Many are viruses and bacteria, but the list also includes plants, insects, fish, mammals, and more. In every case, scientists are sequencing genomes because they want to answer additional research questions.

Biotechnology may help researchers produce clean, renewable fuels.

You might have heard the term green fuel. It's a term used to refer to numerous types of alternative sources of energy—fuels that don't come from nonrenewable petroleum. One green fuel many researchers are investigating is ethanol.Ethanol is an alcohol, but more importantly, it also is a fuel that can run cars, trucks, and other vehicles. Ethanol can be processed from corn and other grains by using enzymes to break down the grain and the sugar it contains, and then adding yeast to the mixture. The microorganism yeast feeds on those sugars, producing ethanol in the process.

Which term names the total collection of DNA in an organism?

genome

genome

the entire set of genetic material of each cell of an organism

Knowing the sequence of an organism's genome is a first step in identifying

the genes in that organism and figuring out what happens when those genes are turned on or off. Using the genome as a guide, scientists can piece together which genes, on which chromosomes, are associated with a growing list of characteristics in organisms.

Genomics is the study of

the whole genome, or the entire set of DNA in an organism.

Why are some scientists studying the bacteria that live in the guts of termites?

those bacteria may contain genes that will help convert plant material to ethanol.