What does science really look like? I spent this summer learning just that. I worked in Dr. Kieber's lab at UNC-Chapel Hill genetically modifying plants using Agrobacterium. To learn more about the lab and the research being done there, click here.
Here are a few pictures of what the lab looks like.
In the Student Activity, we used Agrobacterium to insert a new gene into Arabidopsis (a small weed). This new gene will prompt the plant to synthesize new proteins that will enhance resistance to disease. Here we'll walk through the process of obtaining the new gene to put into the bacteria so that you can see what working in a research laboratory is like!
The first step in isolating DNA is to collect live tissue. In our experiment, we use a strain of Arabidopsis that contains a different allele from our target plant. Because we know that this strain has this alternate allele, we also know that it makes a protein we want our plants to have. The Arabidopsis plants in the green house are pictured below.
Next, we have to get the DNA out of the cells we collected. To do this, we add solutions that cause the cells to break open or lyse. Once this happens, we spin the solution very fast in a centrifuge. This causes the DNA to separate out of the rest of the material. We end up with a pellet of DNA like the one in the picture below.
Once we have the DNA, we need to make sure that we have enough of our gene to run the experiment. To do this, we run a reaction called Polymerase Chain Reaction or PCR. This process uses enzymes to make many copies of the gene of interest. To learn more, click here. After the process is finished, we have a large enough amount of the target gene to work with. Luckily, we have machines that run the entire PCR process for us so all we have to do is add the right enzymes and run one of the PCR machines, which are pictured below.
Now that we have many copies of our gene, we need to isolate it from the rest of the DNA. To do this, we run a process called Gel Electrophoresis. To learn more about this process, click here. Gel Electrophoresis will separate the pieces of DNA by size. We know the approximate length of our target gene so we can find it on the gel. The pictures below show what the gel electrophoresis boxes look like.
Next, we expose the gel to UV light so that we can see the pieces of DNA. Then, we cut the correct band out of the gel and add a series of chemicals that will melt away the gel so that we have only the correct gene in our tube.
The last step in the process is to move the gene into a plasmid so that the bacteria can take it up. We can apply a brief electric shock to the plasmid so that it will open up and the gene can move in. We'll learn more about this process in the Student Activity.