In Episode 6 of Ever Wondered? Series 2, Dr John Watt discusses with various genetic experts how our genes contribute to common diseases including gout, heart disease, depression and obesity. He finds out more about the interaction between genes and environment in each of these diseases, and he gets opinions on what plays the bigger role in who and how we are – genes or the environment?
Genes and gout
To find out the basics about genetics, John goes back to school at Otago University where he has a one-on-one lecture with Associate Professor Tony Merriman. Using some elaborate models of the DNA helix and clever graphics, we find out what DNA is, how it works and what it’s made up of.
Tony’s specific field of interest is in understanding why some people are more susceptible to gout than others. In New Zealand, Māori and Pacific Islanders have far higher rates of gout than Pākehā. However, all three groups appear to have the same prevalence of genetic susceptibility to gout. Tony’s group is looking at what the genetic factors are and how they interact with environmental factors. This knowledge could make a difference in people getting gout and may influence future treatments for gout.
Genetics of heart disease and mood disorders
Heart disease is one of New Zealand’s biggest killers. Scientist Associate Professor Vicky Cameron, University of Otago, is looking at the genetic links to heart disease and particularly why heart disease runs in certain families. Vicky is interested in both the genetic contribution to developing heart disease as well as the genetic contribution to recovery after a heart attack.
John catches up with Vicky in Christchurch and meets one of the heart attack patients involved in her research. Vicky discusses how minimising the lifestyle factors that contribute to heart disease (such as smoking and obesity) are important for people with a strong family and personal history of heart attacks. She explains how international research has shown that non-coding DNA (also called junk DNA), rather than specific genes, seem to be involved in susceptibility to heart disease. Her lab has been examining heart tissue from patients who carry the genetic variant in their non-coding DNA. Vicky and her team have discovered a protein transcription factor linked to this non-coding DNA that may contributing to the development of heart disease.
Physical disease isn’t the only illness that’s being linked to our genes. Scientists such as University of Otago’s Professor Martin Kennedy are now looking to our genes to better understand mood disorders and mental illness.
Martin shows John around his lab and explains how he’s been able to uncover a biochemical pathway in the brain that may be involved in mood disorders such as depression, schizophrenia and bipolar disorder. The pathway contains a chemical called BH4, which is involved in producing neurotransmitters that transmit messages around the brain.
Martin outlines how the drugs used to treat depression and bipolar disorder seem to influence this pathway. One of these drugs is valproic acid. Martin’s research has shown how gene expression is altered in patients taking this drug. He discusses with John how he’d now like to understand how the drug works – whether it acts directly on the DNA or whether it acts through another mechanism. If they can understand how the drug works, they can potentially improve its use as well as improve their understanding of mood disorders.
Genes and maternal health
Can our genes be influenced by the maternal environment while we’re still in the womb? Dr Christine Jasoni, University of Otago, thinks they can. She takes John on a tour of her lab and explains how the health of a mother can ultimately affect the circuitry of their unborn baby’s brain. She explains to John that, for example, obese or diabetic mothers may change the gene expression of their offspring in the womb. This may alter the way in which the foetal brain is wired, which then influences the child’s susceptibility to diabetes or obesity once they’re born.
Christine uses rodents to explore her hypothesis. After feeding them specific diets, thin brain slices are examined to visualise the proteins and look at the connections between the cells. Her research has shown that the brains of offspring of obese mothers have indeed changed. Even after moderating for the behaviour of the obese mother after birth by cross-fostering, the offspring still have an elevated risk for obesity. Christine would now like to look at whether there are specific times in pregnancy when specific maternal factors might be having an effect on brain development.
To sum up this episode, John revisits our genetics experts to get the final word on the ultimate genetics question. Nature versus nurture – what plays the bigger role in who and how we are?
In conjunction with this episode of Ever Wondered?, your students may enjoy these activities.
In this activity, students use an interactive or paper-based graphic organiser to explore common alternative conceptions about genetics. This activity can be done individually, in pairs or as a whole class.
Genetics true or false
In this activity, students participate in a simulation that demonstrates that both genetic make-up and environmental factors influence an individual’s likelihood of becoming obese.
Obesity risk factors
These are some common student misunderstandings about genetics based on education research. Keep them in mind while teaching – and address them as they come up.
Alternative conceptions about genetics
Associate Professor Tony Merriman used an analogy when he said “genes are like a blueprint from which the house is built” and went on to explain that the gene in the plan needs workers that work off the plan. Analogies are useful models for enhancing student understanding. In this activity, students have an opportunity to learn about the contents of a cell, including DNA, using an analogy of a school.
Inside a cell
In this activity, students extract and observe DNA from a tomato.
Introduction to DNA
Uniquely Me: This context explores the question: What makes me, me? My genes or my environment? It covers many of the science ideas and concepts that are featured in this episode of Ever Wondered? In particular, Dr Christine Jasoni discusses her research in more detail. This context provides a wide range of resources that can be used to support and extend students interested in this area of science.