Kaguya the Mouse
Name Date
Predict
A baby mouse usually comes from one egg and one sperm. Scientists in Tokyo tried to grow a mouse from the DNA of two mouse eggs and no sperm. Could two eggs and no sperm ever make a living mouse?
Circle one. Yes / No
Why?
Watch
- 2 eggs can make a mouse, with some helpyoutube.com/shorts/1ymhrjaj6e0
Word of the day
Imprinting (im-PRIN-ting). In genetics, a tag on a gene that marks which parent the gene came from. The tag controls whether that copy of the gene switches on.
| Word part | Comes from | Meaning |
|---|---|---|
| im- | Latin in- | in, into, on |
| Latin premere | to press | |
| -ing | Old English -ing | the action or process |
- A printing press presses inked letters onto paper. Print comes from an Old French word that means “to press.”
- Baby ducks imprint on the first big moving thing they see, and that’s usually their mom. English picked up the word imprinting in 1937 for this kind of fast learning.
Questions
An embryo is a baby animal at its earliest stage. Eggs and sperm carry the same genes. But put the DNA of two ordinary eggs together, and the embryo stops growing. If the genes are the same, why does a two-egg embryo stop growing?
Hint. In the video, Raven says dad tags often push growth up. Where do dad tags come from?
A clone is an exact copy of one animal’s DNA. Kaguya had no dad. Her DNA came from the eggs of two different female mice, a newborn and an adult. Is Kaguya a clone of either mouse that gave her DNA?
Circle one. Yes, of the newborn mouse / Yes, of the adult mouse / No, of neither mouse
Hint. A clone gets all of its DNA from one animal. How many mice gave Kaguya DNA?
Raven names Prader-Willi syndrome in the video. Many kids born with this health condition are missing a few genes from dad’s chromosome 15. A chromosome is a long strand of DNA that holds many genes. These kids still have mom’s copy of those genes. Why can’t mom’s copy of those genes fill in for dad’s missing copy?
Hint. In the video, Raven says only one parent’s copy of some genes is supposed to switch on. What happens to the other copy?
It took about 460 tries to make one adult mouse, Kaguya. In 2004, scientists said this method was far from being used in people. Why was a two-egg baby still far from use in people in 2004? Give two reasons.
Hint. First, count the tries the scientists needed. Then think about the two changes the eggs needed.
Exit ticket
Eggs and sperm carry the same genes. Why does a mouse still need DNA from both an egg and a sperm?
Hint. In the video, Raven says dad tags push growth up. Which tags come only from sperm? Which come only from eggs?
Sources
- Tomohiro Kono and colleagues, Tokyo University of Agriculture, Nature, 2004
- Philip Leighton, Shirley Tilghman and colleagues, Princeton University, Nature, 1995
- Andrew Keniry, Wolf Reik and colleagues, Nature Cell Biology, 2012
- Yayoi Obata, Tomohiro Kono and colleagues, Development, 1998
- Manabu Kawahara, Tomohiro Kono and colleagues, Nature Biotechnology, 2007
- Yanchang Wei, Cai-Rong Yang and Zhen-Ao Zhao, Shanghai Jiao Tong University and UC San Francisco, PNAS, 2022
- Review by Denise Barlow and Marisa Bartolomei, Cold Spring Harbor Perspectives in Biology, 2014
- MedlinePlus Genetics, US National Library of Medicine, Prader-Willi, Angelman, Beckwith-Wiedemann
- Helen Pearson, “Mouse created without father”, Nature News, April 22, 2004
- John Travis, “Two egg cells make fatherless mouse”, Science News, May 2004
- Vision and Change core concepts and competencies, as summarized in Brownell and others, CBE Life Sciences Education, 2014
- Word origins from Dictionary.com: imprinting, imprint, in-, print, -ing, genome, press, pressure, impression, impressionism, espresso
- Spanish and French words from Wiktionary: imprimir, imprimer