My PhD research explained at a 7th grade level 8

One of the classes that affected me the most taught me that I should be able to explain my research to a 7th grader. This is because if you aren’t a specialist in my field, a lot of what I did wouldn’t be understandable with all the jargon and background knowledge I have. So it’s best to be able to explain what you do to people of almost any age and background. It’s not about “dumbing it down” by taking away important concepts, it is about explaining in plain language what I did and why it was important. I feel strongly that this sort of lesson should be included with any PhD so that communication can happen across all breadths of experience and knowledge.

So we will start with the basics. Most living organisms have DNA in their cells. DNA is like a blueprint the cells can read. DNA tells the cells how to make proteins (building blocks) that are necessary for life.

DNA is also like spiraling ladder, with sides and rungs. Each rung is made up of two “bases”, one on each side of the rung. There are four types of bases, with the initials A, T, G, and C. For the DNA to be read and make proteins, the DNA ladder unzips into two separate sides, each with a bunch of half rungs. So for example, a short string of DNA might read ATGGCA along its rungs.

Sometimes there are repetitive strings of DNA, for example a sequence of DNA might read AGCTATATATATAC. The TA is in bold because it is repeated several times. You know how when you are trying to copy down a number that has a lot of 0s in it, it’s easier to be off by a zero or two? Well it’s the same for DNA and repetitive sequences. So the DNA when it is copied sometimes ends up with more or fewer repeats. This is heritable– you get a pattern of repeats from your mom and dad.

By looking at the number of repeats, you can tell which organisms are related to others. For example, you will share 50% of your repeats (called microsatellites) with your parents and siblings. Looking at the number of repeats you can tell if organisms are aunts, grandparents, cousins, etc.

The plant I was studying is called Lupinus nanus, also called the sky lupine. These are wildflowers in the pea family, related to the bluebonnets you see so predominantly in Texas. The small flowers are a bluish purple with some ornate petals. The first part of my research was to find these microsatellites (repeats) in Lupinus nanus so that we could tell which plants were related to each other.

I wanted to do research on how human-affected changes in the environment impacted how populations of the plant developed. At first I thought I would study plants grown on contaminated soil (from old copper mines), but I found ranchers were not excited about letting me onto their property to look at contaminated soil, lest the government get wind of the contamination.

One day Brad drove me out to Folsom Lake, which is a lake just outside Sacramento, California. It was October, and I was simply scouting locations. I did not expect to find any plants because just like other wildflowers, Lupinus nanus generally starts growing in the spring and dies off in the fall. We were walking around the lake bed and I saw a lupine flower stalk! I looked around for more, and found a small population of lupines at the high water mark that were flowering! It was totally the wrong season for them!

I wondered why these plants were growing so strangely, and realized that it might have something to do with the lake levels. You see, Folsom Lake is used to make hydroelectric power, so the lake level fluctuates during the day and year. This is due to the amount of water needed to make power, the amount of power needed (like AC in the summer!), and the amount of snowmelt feeding into the lake. My research questions were:

Why are there Lupinus nanus plants growing at such an odd time?

and

Is this separate growth of these plants something that is associated with DNA differences between the normal and strange plants? Or do the normal and strange plants basically have the same DNA?

I did many many experiments, collected DNA from hundreds of plants, and ran thousands of reactions to count the repeats in different places in the DNA.

At the lake’s high water line, the water level changed a lot during the day. I found out through experimentation that these plants would start to grow because of that fluctuation. So the lake environment was causing a change in how the plants grew.

By using the microsatellites (repeats) I was able to determine that the two groups of plants basically did not have different DNA. In other words, both plants were part of the same population. It’s just some plants were in that perfect little area that made them grow at the strange time.

I had a lot of fun doing my research! It was also so beautiful! I will post below a few pictures of the plants and environment. All the plants featured are Lupinus nanus. They are fresh green plants with a blue/lavender hue of their petals. The flowers grow on a stalk that sticks up. When the plants are done blooming, the flowers turn into pea pods, and the seeds are like tiny peas.

To read the full dissertation or to see more pics, you can download it from the following link: https://escholarship.org/uc/item/38d7k918