The Birth of Epigenetics: the Agouti Mouse Study

In 2003, Professors Randy Jirtle and Rob Waterland conducted a groundbreaking study at Duke University on agouti mice, revealing that identical genotypes can result in different phenotypes due to gene expression changes. The study showed that a transposon near the agouti gene caused obesity and yellow fur in mice. By altering the diet of pregnant mice, the researchers demonstrated that environmental factors could change gene expression, leading to healthier offspring. This study was pivotal in the field of epigenetics, challenging long-held beliefs about inheritance and disease susceptibility.

What was the main finding of the agouti mouse study conducted by Jirtle and Waterland?

• Genetic mutations are the sole cause of obesity in mice.

• Mice can change color based on their environment.

• Identical genotypes can result in different phenotypes.

• All mice have the same genetic expression.

What is a transposon and how does it affect gene expression?

• A fixed DNA sequence that silences genes.

• A protein that inhibits gene expression.

• A viral DNA segment that can move and alter gene expression.

• A stable DNA segment that enhances gene expression.

How did Jirtle and Waterland attempt to change the phenotype of the mice?

• By altering the mice's genetic code directly.

• By changing the diet of the mother mice.

• By exposing the mice to different temperatures.

• By using gene-editing technology.

What was the outcome of feeding the mother mice a diet rich in methyl groups?

• The mother mice became infertile.

• The offspring had a higher proportion of lean brown pups.

• The offspring developed new genetic mutations.

• The offspring were all yellow and obese.

What did the study reveal about the relationship between a mother's diet and her offspring's genetic expression?

• Diet can causally influence genetic expression.

• Genetic expression is solely determined by inherited genes.

• Diet has no impact on genetic expression.

• Only environmental factors after birth affect genetic expression.

How did the study impact the field of epigenetics?

• It showed that epigenetics was irrelevant to disease susceptibility.

• It confirmed that epigenetics was a myth.

• It proved that epigenetics was only applicable to plants.

• It opened up new research avenues in epigenetics.

What was the significance of the study in terms of scientific beliefs?

• It showed that scientific beliefs are always correct.

• It challenged the belief that only genes are inherited.

• It reinforced the idea that genes are the only inheritance.

• It suggested that diet has no role in genetic inheritance.