Recombinant DNA and Accountable Talk

A few weeks ago, I observed some of our seniors making presentation in Mr. Hesse’s Ethics in Science course, which is a part of our Capstone program. I was particularly impressed with the content knowledge the students had acquired through their research. The students love this course and are actively debating the most current of issues, but the best part of the class for me was that the students were held to a high standard, for Mr. Zell who teaches genetics at Newman, was listening to the presentations and asking pointed follow-up questions. This to me was a great example of “Accountable Talk,” one of Lauren Resnick’s Principles of Learning.


 Talking with others about ideas and work is fundamental to learning.  But not all talk sustains learning.  For classroom talk to promote learning it must be accountable – to the learning community, to accurate and appropriate knowledge, and to rigorous thinking.  Accountable talk seriously responds to and further develops what others in the group have said.  It puts forth and demands knowledge that is accurate and relevant to the issue under discussion.  Accountable talk uses evidence appropriate to the discipline (e.g., proofs in mathematics, data from investigations in science, textual details in literature, documentary sources in history) and follows established norms of good reasoning.   Teachers should intentionally create the norms and skills of accountable talk in their classrooms.

Mr. Nowell Hesse, who teaches this course, shared the three topics the students were investigating: 

1)      Gene knock-in, also known as recombinant DNA: a genetic engineering technique whereby genes from one organism are transplanted into another organism leading to the production of a new protein or biological molecule in the second organism. This has been used to produce human insulin among other molecules in bacteria; it could potentially be exploited as a therapeutic agent to treat a variety of diseases in humans; it has also been used to produce genetically modified plants that are resistant to herbicides or insects.

2)      Gene knock-out: several methods have been developed that interrupt the expression of certain genes in certain organisms; this is a powerful research technique for discovering the function of certain genes / proteins; possible therapeutic agent for disrupting the expression of defective genes or unwanted genes.

3)      Genetic screening: new screening techniques allow doctors to determine the genotype of individuals, including developing fetuses. Ethical issues such as selective reproduction, directed evolution, and selective abortion arise from this new technology.

Students later viewed the following TED Talk, entitled “It’s Time to Start Questioning Bio-engineering.” I spoke with two of our seniors, and they were incredibly enthusiastic about their upcoming debate on the subject.

Incidentally, if you have not spent some time watching the Ted Talks, you should give them a try. Their headline is “Ted Talks: Riveting Talks by remarkable people, free to the world.” They also have a great IPad app.