Advancing Epigenetics Towards Systems Biology

The calico cat


Rainbow the ‘genetic’
mother of CC
Photo courtesy of the College of Veterinary Medicine and Biomedical sciences, Texas A&M


Guinness the calico cat
Photo by Brona McVittie


Carbon Copy with her surrogate mother in 2001
Photo courtesy of the College of Veterinary Medicine and Biomedical sciences, Texas A&M

The cloned moggy with two mums.

Brona McVittie reports :: June 2006

I named our last cat after the famous Irish black beer because her mottled fur coat reminded me of a settling pint of Guinness. Had I £25 000 to spare, and were Guinness still alive, I might consider getting her cloned. But I'd be a little miffed with my new moggy because it's unlikely she would resemble my beloved puss. The first cloned cat, Carbon Copy, was created in Texas from a calico cat like Guinness. But the kitty didn't turn out to be a 'carbon copy' despite having identical DNA to her genetic 'mother' Rainbow.

This can be partly explained by an epigenetic phenomenon known as X-inactivation. Calico cats are always female, which means they have two X chromosomes in every cell. The gene for orange coat colour is located on the X chromosome, but there is another version (allele) of this gene that results in black fur. In female cats (XX), one X chromosome gets switched off (inactivated) in every cell, so if a female inherits one of each allele (orange and black) then her coat will exhibit patches of both colours.

The process of inactivation is random, which is why cloning a calico cat will never produce the same pattern. In the case of Carbon Copy, she was created from an egg cell that had its nucleus replaced with one from Rainbow. Although the cell from which Carbon Copy was cloned had one inactive X, the developmental programme reactivates both X-chromosomes, and the process of inactivation recurs in a random manner. This results in an entirely different coat pattern even when two individuals are genetically identical.

The handful of millionaires that have banked the cells of their prized pets may be paying over the odds for an animal which has no guarantee of being the same. Instead of paying over £400 for the privilege and £50 annual maintenance, plus the rather exorbitant cloning fee when their pet pops its clogs, perhaps they might be persuaded to take in one of the many millions of abandoned pets that will otherwise be euthanised.

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EpiGeneSys Final
Meeting in Paris

Thur. 11 February 2016 - Sat. 13 February 2016

More than 280 scientists attended the fifth Annual Meeting of EpiGeneSys. The conference kicked off with a talk by coordinator Geneviève Almouzni, Director of the Research Center at the Institut Curie, highlighting the achievements of the network over more than five years...

Maison des océans - Paris Read more


The Non-Coding Genome ...

December 3-4 th, 2015

The last training workshop of the EpiGeneSys network

Hotel Mediterraneo - Rome, Italy Read more

Paris / TriRhena Chromatin Club

July 9th, 2015

...exciting talks and network with members of the Chromatin community!

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June 11st-12nd , 2015

... learn about current approaches to single cell epigenetics and to meet up and network with...

Montpellier, FranceRead more

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