what mothers eat matters we use rats as a model for how humans work because we can control their...
TRANSCRIPT
What Mothers Eat Matters
We use rats as a model for how humans work because we can control their diet and they quickly have many offspring. Rats are also very similar to humans physiologically.
Studying this relationship using a rat model
How did we measure potential fertility?
Females are born with a limited number of eggs; all waiting halfway through meiosis. Each month some will go through four developmental stages and be ready for fertilisation. We counted the number of eggs developing in each treatment group to determine whether diet influenced egg development.
An egg at the primordial stage
The primary stage
The secondary stage
A mature antral egg follicle ready to be released for fertilisation
Analysing changes in gene expression could explain these differences in egg development
Thanks very much to the government-funded NZ Mathematics and Sciences Teacher fellowship scheme, administered by the Royal Society of NZ, that has allowed me to contribute to this research. I have had fantastic support from the scientists at the Liggins Institute, my host Dr Deborah Sloboda in particular; without her enthusiasm and encouragement I could not have done any of this! Also, a huge thank you to Jacquie Bay and Helen Mora for opportunities to participate in their amazing LENS programme.
Jane Cunningham teaches science, biology and chemistry at Avondale College.
Teacher Fellow 2008, hosted by the Liggins Institute, University of Auckland
Evidence suggests our health is influenced by conditions we experienced in our mother’s womb
Results suggest pregnant rats fed a high-fat diet programmed their daughters to go through puberty early and also use up their eggs more quickly.
Research already suggests that if our mother ate a high-fat diet when pregnant it increases our risk of obesity, diabetes and heart disease later in life - even if we eat a healthy diet!
Back in the classroom...
Examples in Junior Science: •Nature of science: experimental design, using animal models and ethical issues
•Food and digestion: importance of a healthy diet
•Reproduction : early puberty and the problems this can cause for our teenagers.
Jane Cunningham, Avondale College
Acknowledgements
Mother ate balanced dietMother ate high-fat dietMother ate high-fat diet only during pregnancy
With many women making choices about nutrition during pregnancy, high-fat diets may be contributing to difficulties getting pregnant and also harm their babies long term health.
Results
Examples in Year 13 Biology:•How the environment affects our phenotype by changing gene expression
•Hormones and the control of gene expression in eukaryotes
•How biotechnologies are being used in current research
•Epigenetics and how it is changing our understanding of inheritance and evolution.
For more information or resources, please email me: [email protected] primary secondary Antral
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Mothers ate a balanced diet
Mothers ate hig-fat during pregnancy only
Mothers always ate highfat
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Graph showing the relative numbers of developing eggs in the ovaries of offspring
Crush up the ovaries and extract all the RNA.
Copy the RNA into cDNA which is more stable
Use PCR to make multiple copies of the cDNA
Use quantitative PCR to calculate differences in gene expression across the rat groups
Use gel electrophoresis to check that cDNA is not contaminated
Daughters fed a balanced diet
Daughters fed a high- fat diet
Daughters fed a balanced diet
Daughters fed a high-fat diet
Mothers ate a balanced diet
Mothers ate high- fat diet when pregnant
Mothers always ate high- fat diet
Daughters fed a balanced diet
Daughters fed a high fat diet
Some of the rats
weighed up to 1.5kg!
We alsoinvestigated low-fat
diets
This research provides an interesting context for many skills and concepts:
This graph demonstrates that if pregnant rats are fed a high-fat diet during pregnancy and lactation their pups will go into puberty earlier. This may be the case in human studies. So, is the fertility of these children affected?
Age (days)27 29 31 33 35 37 39
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Mother fed a balanced diet
Mother fed a high-fat diet during pregnancyMothers fed high- fat diet from birth
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Do maternal diets also influence reproduction?
Age at puberty