No kidding, methyl groups make us complex, according to a headline in Chemical & Engineering News (8 February 2010). The researchers propose that as DNA is transcribed into mRNA, the chemical ““decorations”” of nearby histone proteins determine how the RNA is chopped and, thereby, how biological complexity is attained. The article is about epigenetics, the cutting-edge science that involves changes in gene expression (phenotype) that do not alter the DNA sequence (genotype).
So, might child abuse affect our genes? Can cocaine actually reprogram the way our brain works? Does what my mom ate affect my children? Does this explain why identical twins aren't identical although they have the same genotype? Does popping a B-vitamin protect me from the effects of multiple martinis? If I'm bilingual, does that mean I may be less prone to Alzheimer's? What is so important about archaeal histones being similar to my histones? Does it matter if my genes are on or off?
How does my genome work? And what's this about an epigenome? If talk is growing in research and the public arena about this topic, shouldn't teachers in our biology classrooms be talking about it too? The April issue of The American Biology Teacher provides stellar resources to both enhance your understanding of epigenetics and facilitate educational opportunities for studying multiple aspects of genetics with your students, including epigenetics, in thought-provoking, inquiry-based ways. And our editor has not forgotten to keep our fingers on phylogenetic trees, biotechnology, and forensic genetics, as well. The idea of genes being affected by the environment is not new. Naturalists as far back as Jean Baptiste de Lamarck and even Aristotle have associated environmental changes with the inheritance of acquired traits. But it was Conrad Waddington who ““formulated the concept of the epigenetic landscape, published in its mature form in 1957, to represent the way that developmental decisions are made”” (Slack, 2002). That is, how changes outside the DNA can bring about the differentiated organism, each individual experiencing different environmental changes and thus being unique to some extent.
Time Magazine (12 January 2010) supplies a neat analogy to distinguish genome and epigenome in a way that suits our 21st-century kids: ““if the genome is the hardware, then the epigenome is the software.... ‘‘I can load Windows, if I want, on my Mac,’’ says Joseph Ecker, a Salk Institute biologist and leading epigenetic scientist. ‘‘You're going to have the same chip in there, the same genome, but different software. And the outcome is a different cell type'”” (Cloud, 2010).
So, let's dig into the excitement of life-long learning! In the first Quick Fix, ““Using an Active Learning Approach to Teach Epigenetics,”” Colóón-Berlingeri describes active-learning experiences that involve the genotypic and phenotypic differences between monozygotic twins and the role of epigenetic mechanisms in these differences, with molecular mechanisms leading to epigenetic changes as well as techniques used to study them.
In the second Quick Fix, you can use pipe cleaners to ““bring the tree of life to life,”” overcoming known challenges associated with tree thinking, especially helping students see the evolutionary relationship between the Archaea, animal, and plant domains, among others.
Although inactivation of the X chromosome is most closely associated with epigenetics, likely many of your students will find their interest piqued by Offner's article on the Y chromosome from the point of mutation, recombination, mammalian sex determination, and the evolution of sex determination in mammals, most notably humans. Offner also contributes a How-To-Do-It comparing chimp and human beta hemoglobin. Genetics in the 21st century requires that our students have experience using NCBI (National Center for Biotechnology Information). Access the genome databases and practice using the powerful tools associated with searching DNA sequences from labs all over the world.
““Using Harry Potter to Introduce Students to DNA Fingerprinting & Forensic Science,”” hook student interest in introductory forensic science with RFLP (restriction fragment length polymorphism) analysis using inexpensive materials to interpret data from a mock crime scene. Most importantly, dispel the common misconception that the sophisticated science involved in crime-scene analysis is always infallible.
Involve your class in a learning cycle to discover the mechanism behind a physical deformity (always an attention grabber) in ““Using the Mystery of the Cyclopic Lamb to Teach Biotechnology.”” Discover the processes of signal transduction, polymerase chain reaction, gel electrophoresis, restriction enzyme digest and ligations, cloning and transformation, the nature of scientific inquiry, and practice hypothetico-deductive reasoning. It's a real-world science connection, especially for the high school classroom.
Then use Billingsley and Carlson's lesson, ““Epigenetic Effects of Diet on Fruit Fly Lifespan: An Investigation to Teach Epigenetics to Biology Students,”” especially if the question ““Does what my mom ate affect my children?”” intrigues students.
Finally, don't close this journal until you have explored ““Genetics in the 21st Century: The Benefits & Challenges of Incorporating a Project-based Genetics Unit in Biology Classrooms.”” If you have been looking for relevant genetics, you have definitely come to the right professional development association to find that —— the NABT!