EXHIBITION GUIDES

Exhibition Guide for Putting DNA to Work

Station 1: Orientation to DNA (Introduction and Probe the Sequence)
The main messages of this station are:

• DNA is shared by all living organisms.
• There is great similarity in the DNA sequences of different species.
• DNA sequences are more similar than different among individuals within species.
• DNA is found in nearly every living cell in all organisms.
• The DNA molecule is encoded with information, which can be visualized as a series of letters.
• The two strands of the DNA molecule are complementary.
• Short DNA probes have a higher probability of finding matches in a DNA sequence than longer probes, but DNA sequences are not random and the probability of finding matches is not necessarily obvious.
• An individual has two sets of sequences, one of which is inherited from each parent.

This station provides an introduction to DNA structure, an exploration of DNA sequence, and a brief overview of inheritance. Students can use an interactive exhibit to see how many genes they have in common with a wide range of organisms such as the fruit fly and mouse. The centerpiece of this section is the probe tower. With this interactive device, students can create their own short, electronic DNA probes and look for matches in part of the human genome. Surrounding the tower are explanations about the structure and function of DNA. This station ends with a brief explanation of inheritance.

Station 2: Diagnosing Disease
The main messages of this station are:

• Some human diseases are linked to mutations in inherited sequences.
• Genetic testing can reveal whether a person has inherited copies of such mutations.
• Early detection can improve health management and actually prevent some genetic diseases.

Station 2 features two significant inherited diseases, hemochromatosis and sickle cell anemia. Assisted by an interactive computer display explaining mutations, students will discover that a single base pair mutation results in the malformation of blood cells. They will use an interactive video to test a family for a mutation in the gene that causes hemochromatosis and will see whether the children are carriers or are affected.

Station 3: Find the Sequences that Make Us Unique (Forensics)
The main messages of this station are:

• Although people differ by only 0.1% of their DNA sequences, each person is unique.
• Individuals are identified using sequences that tend to show greater variability among individuals.
• DNA identification is based on the very low probability that multiple individuals will share identical sequences in these regions.

In this station, students will learn about the FBI’s CODIS system. Using a wall-sized display, students will match the sequences of DNA collected at a crime scene with sequences from suspects. They will see the comparisons of the short tandem repeats at the 13 locations used by the CODIS system. A short video about the impact of DNA testing in the courtroom helps to put the display in perspective.

Station 4: Sequences that Improve Crops
The main messages of this station are:

• Modern produce hardly resembles its ancient wild-type ancestors.
• Humans have been modifying crops from about 10,000 years ago.
• Scientific crop development began about a century ago, and genetic engineering of crops began in the 1990’s.

This station focuses on the long history of human manipulation of crop plants through selective breeding and, more recently, genetic engineering. The station focuses specifically on modifications made to the corn plant. Students will be able to see the differences between corn and its putative ancestor, teosinte. They will explore the amount of acreage planted with genetic modified plants worldwide. By moving a slider next to a physical representation of each of the chromosomes in a corn cell, students will see the locations of different genes and how mutations in those genes contribute to a wide variety of phenotypes.

Station 5: Can DNA Sequences Protect Public Health?
The main messages of this station are:

• Knowledge of DNA sequences helps to identify novel viruses and bacteria.
• Microarrays are a new tool for detecting relationships between known and emerging infectious agents.

Station 5 features cutting-edge technology that was used to uncover the virus responsible for the SARS epidemic in early 2003. Students will learn how microarrays, which allow scientists to examine thousands of genes at one time, are being used to identify new infectious agents. They will see the actual sequences used on the arrays and will be able to identify for themselves the family of viruses that includes the SARS virus.