Human Practices

Overview

Rose-Hulman hosted the ExxonMobil Bernard Harris Summer Science Camp for middle-school aged students. These students were exposed to a variety of science and engineering fields over the course of two weeks. The RHIT iGEM team had a chance to work with two groups of 22 students in three separate sessions to provide them with a foundation in genetics, genetic engineering, and synthetic biology.

Session 1

During the first session, the students were introduced to the concept of information flow, genes, how genes are responsible for various characteristics, and how they are created in cells. The students were taught how DNA is formed and the structure of DNA in cells. Once the basics of nucleotides and DNA were understood, the students also learned about how nucleotides are decoded into amino acids.

The activities during the day included the students making beaded keychains with different colors representing different nucleotides (A-red, T-yellow, C-orange, G-blue). Each strand was to start at the 5’ end (green or pink glow-in-the-dark bead), and end at the 3’ end (purple or yellow glow-in-the-dark bead). The students were taught that DNA should be read 5’ to 3’. It was useful to show them an analogy by writing a word on the whiteboard such as “board” and showing that the word makes sense when read from left to right, but from right to left it spells “draob” which is nonsense.



Each student was to make one of four sequences provided. Once finished with their first strand, they used it to create a complementary strand. When the students were finished with their double stranded DNA sequence, they were given a sequence decoder in order to see the amino acid sequence. Each sequence decoded into amino acids that spelled out the word “science.”

Session 2

During the second session, we expanded the students’ knowledge of genetics by focusing on RNA. We explained that RNA is the molecule that is decoded by ribosomes to form chains of amino acids. We also explained that some amino acids are encoded by multiple codons, which is why in session one, although there were four different sequences, each chain spelled out the same word. The students learned that RNA uses a different nucleotide base, uracil, which is used in place of thymine. A major talking point was the explanation that the RNA strand is complementary to the second (complementary) strand of DNA, and is therefore the same as the original strand (with the exception of T→ U). Another major point made during the session was the explanation that there are incredible amounts of possible gene combinations (mentioning the concept of a gene pool), and that gene combinations are related to chance.

The activity during the second session involved the students creating RNA sequences based on the DNA strands made in the first session. For RNA, a purple bead was used for uracil, and the other nucleotides remained the same colors. Once the students were finished with this task, they were given another “secret code” which defined each letter of the alphabet with a different three-nucleotide sequence. The students were then to make a sequence that, when decoded, would spell out their initials. After this was completed, the students were given another task - a sheet of paper with various traits and genotypes for them (e.g. AA-large nose, Aa- medium nose, aa-small nose) and a blank face to draw the traits on. They rolled two dice to determine which genotype to draw (two even numbers - AA, two odd numbers - aa, one even and one odd number - Aa). The resulting pictures were to demonstrate that, due to chance, there can be many different combinations of traits, and each student ends up with different outcomes.

Session 3

During the third session, the students were introduced to the idea of a genetic circuit. We described to them what the iGEM competition is and what types of projects are involved in synthetic biology. Using their knowledge of DNA and genetics obtained in the first two sessions, we explained to them that researchers are able to take different sequences of DNA that have different functions, and build systems that will give a desired result. We explained the basics behind terminators and promoters as examples of sequences with different functions. The students also learned about inducible and repressible promoters.

The activity for the session included the students using printed-out puzzle pieces labelled as various parts (inducible promoter, repressible promoter, gene, terminator, etc.). They were given a series of challenges to test their understanding of the concept of genetic circuits. For example, the students were first asked to create a system to result in the expression of a generic gene (promoter-gene-terminator), and the challenges increased in complexity to systems including an inducible and a repressible promoter. Once the students completed the challenges, they were asked to use their creativity to create their own unique system and explain what the system would result in. The students grasped the concept very well and were very interested in the idea of synthetic biology and genetics in general.