Activity 1: Splicing DNA

1. Ask students what keyboard functions they use frequently on the computer. Some might give answers such as the delete key, the number keypad, copy and paste, etc. If no one answers “copy and paste” or "cut and paste" then guide students to that answer by asking leading questions such as, "How do you move information quickly on a computer without having to type the entire thing?" Inform students that the same “copying/cutting and pasting” concept can happen with DNA.
2. Pass out the Splicing DNA handout to each student. Review the basic structure and function of DNA, including the four nitrogenous bases of DNA and sugar phosphate backbone. Students should also be able to discuss the purpose of DNA and how information is stored.
3. Read through the instructions found on the Splicing DNA handout with your students.
4. Be sure students understand that each DNA strand on the handout has been labeled and identified as DNA 1 and DNA 2. Complete the following steps as outlined in the handout.
   1. Color each DNA strand a different color (DNA 1 contains the desired trait and DNA 2 is the receiving strand).
      • If you would like students to label the sugar phosphate backbone and nitrogenous bases, then this step can be added.
   2. Cut between the 2 solid lines on DNA 1 (this section produces the desirable protein).
      • In this step, students will need to determine which section of the DNA 1 strand is the desirable trait (the segment between the solid lines). Relate to students that this is the section that needs to be "cut and then pasted." 
   3. Cut out the DNA 2 strand to prepare for splicing.
   4. Carefully make ONE cut on the dotted line of DNA 2.
   5. Splice (insert) the cut-out section of DNA 1 into DNA 2 (where the dotted line was), and secure with tape. Your spliced DNA strand should now be longer than before and contain a different colored section.
5. Review the scientific process of gene splicing, and ask students where this procedure could be useful. 

Activity 2: Spider Goats

1. Using the Spot the Difference PowerPoint, display the two different pictures of goats on the board (regular goat vs. a spider goat). Ask students the following questions:
   • What is physically different about these goats? (Nothing is physically different. However, the goats on the right are called "spider goats." These goats look and behave like any other goat.)
   • How are goats beneficial to society? (Students might answer that goats are used for pets or raised on farms for meat and milk. Inform students that this breed of goat is considered a dairy breed because it produces milk efficiently. However, the spider goat (on the right) produces something extra in its milk.)
2. Leave the picture of the spider goat on the board and write “Transgenic” next to it. Define the word as an organism that contains genetic material that was artificially introduced from an unrelated organism. Discuss transgenic organisms and this particular spider goat on the wall. When asking the questions, let students brainstorm and discuss ideas as a class. Ask the following analytical questions:
   • Why is this goat called a spider goat? (It contains a DNA gene from spiders which helps lactating female goats produce the spider silk protein in their milk.)
   • Why would someone consider these transgenic spider goats to be good and beneficial? Provide reasoning. (Spider goats are not harmed during the process of producing silk. Their milk contains the spider silk protein which can be used to replace Kevlar for bullet-proof vests, parachutes, and medical sutures/binding.)
   • Why would someone consider spider goats to be bad? Provide reasoning. (Some people might argue that this is unnatural for goats to produce spider silk.)
   • Why do you think goats were used for this particular production? Why not cows or sheep? Provide reasoning. (Cows require more space and feed; goats are smaller and easier to manage. Dairy goats can produce 6-12 pounds of milk per day while sheep are mostly used for meat and wool.)
3. Show the NOVA's 'Making Stuff' Explores Spinning of Steel-Strength Spider Silk video clip to students. 
4. Discuss the video clip, and refer back to the gene splicing activity. Consider using the following questions and ideas to guide a discussion:
   • On your gene splicing activity, you copied the desirable gene from DNA 1 and pasted it into DNA 2. What was the desired gene in spiders that scientists “copied and pasted?" (The gene in a spiders’ DNA that produces spider silk.)
   • By inserting the desired spider silk gene into a goat’s DNA, that goat now contains a specific protein. This gives goats the ability to do what? (Produce spider silk in their milk.)
   • Why does the spider silk come out in the milk? (Scientists took the silk-producing gene from spiders and pasted it among the DNA gene of goats that prompts milk production.)
   • Students should now be able to relate DNA 1 to “Spider DNA” and DNA 2 to “Goat DNA." The section they copied is the silk-producing gene. Where they inserted this gene into the goat, codes for milk production.

It's important to be sure your students understand that spider goats do not produce the actual silk in their milk. The milk looks just like any other milk. However, it contains an additional protein that can be extracted from the milk and used to make synthetic spider silk with the same beneficial properties.

*If you use interactive notebooks, this gene splicing activity can be inserted into students’ notebooks and then folded to open and close.