To explore issues surrounding DNA microarray technology.
In this lesson, students will conduct activities from a module called DNA Chips: A Genetics Lab in the Palm of Your Hand. This module is part of the National Institutes of Health Snapshots series, which focuses on a single area of biomedical research to help students understand how science, people, ethics, and history all fit together. Each Snapshot includes a classroom activity to help students understand the scientific concepts, a short summary of the issue, and diagrams that can be turned into overheads. The module for this lesson is about the DNA microarray, also known as a DNA chip.
Basic concepts covered in this lesson include:
- The nucleotide sequence of DNA encodes instructions for making proteins
- Double-stranded DNA contains two complementary DNA sequences, which can be separated and recombined
- mRNA carries protein-making instructions from the nucleus to the ribosome
- A cell’s genes change activity in response to outside stimuli
- Small differences in a DNA sequence between individual people affect everything from their eye color to their chances of getting heart disease
This is not an introductory lesson. Students will need to have had some instruction and experience with these concepts before doing this lesson. Learning about DNA chips can provide a motivating context in which to reinforce and expand upon these concepts.
The Teacher's Guide for the DNA Chips' site has a suggested three- or four-day class schedule that utilizes all of the resources available on the NIH module. In this lesson plan, we have selected some of the resources to construct a briefer learning activity for your students. The module contains many more activities and resources than those which we have highlighted below. If time permits, you should supplement the suggestions below with many of the other activities, some of which are highlighted in the Extensions section of this lesson.
Students should read on their own the following section: Why you need to know about DNA Chips. This brief overview introduces the topic and provides students with a list of the basic concepts they need to know to understand DNA chips. Then, discuss the article, giving students an opportunity to put into their own words why they think this information is important. This would also be a good time to go over the list of concepts to provide a brief review for students.
Begin by conducting Activity I. Using Chips for Sequencing: A Fictional Exercise with the class. This activity can be found in the Student Handout provided in the Teacher's Guide (page 7). In this activity, students will determine the sequence of an unknown DNA molecule, using the kind of data that researchers get from a DNA-sequenced microarray. Answers can be found on page 5 of the Teacher's Guide.
Then have students read A Genetics Lab in the Palm of Your Hand. Students can read this online or you can print out the activity from pages 3, 4, 5, and 9 of the student booklet. If the printout is not in color, it may be better for students to access the html file online: DNA Chips: A Laboratory In The Palm Of Your Hand.
Students should work in pairs to go over this resource. Make sure that they click on and review the section that explains how DNA chips work. After student pairs have completed the activity, conduct a class discussion to review what they have learned and to identify any areas that need further clarification.
Conduct the activity, Using Microarrays for Gene-Expression Analysis: A Real-Life Story of Cancer Diagnosis, with the class, using the Student Sheet provided in the Teacher's Guide (page 9). This activity is Part II in the student handout. In this activity, students will analyze gene-expression data to diagnose two kinds of leukemia.
Use the Summary Questions in the Student Handout to assess student understanding of the concepts in this lesson. Answers can be found on page 6 of the Teacher's Guide.
These activities, which are included in the DNA Chips module, can be used to extend the ideas in this lesson. Classroom suggestions for these activities are included in the Teacher's Guide.
- Archana Nair, Making Microarrays On An Industrial Scale
- Social Impacts: DNA Dragnet
- Story of Discovery: DNA Chips