Xist and calico cats: How extra genes on X chromosomes get turned off

October 29, 2013 by Bill Hathaway
Xist and calico cats: How extra genes on X chromosomes get turned off

Females carry two copies of the X chromosome which—unlike the male's gene-poor Y chromosome—are home to 1000 genes crucial to development. So how does the developing female embryo inactivate duplicate genes along the chromosome, a process that explains the random mix of orange and black color patterns of the calico cat?

Researchers at Yale and collaborators at Massachusetts General Hospital add new details to this complex molecular choreography. Matthew Simon's laboratory at Yale, together with two other labs, studied a large molecule of RNA called Xist—X-inactive specific transcript—that is expressed only in cells where genes along X chromosome are inactivated.

They found that Xist does its job in a two-step process, beginning in a gene-rich environment along the chromosome and then spreading to regions where genes are sparser.

For more details, see the study published online Oct. 27 in the journal Nature.

Explore further: New study rewrites textbook on key genetic phenomenon

More information: www.nature.com/nature/journal/vaop/ncurrent/full/nature12719.html

Related Stories

Research sheds light on M.O. of unusual RNA molecules

July 5, 2013

(Phys.org) —The genes that code for proteins—more than 20,000 in total—make up only about 1 percent of the complete human genome. That entire thing—not just the genes, but also genetic junk and all the rest—is coiled ...

Recommended for you

Expanding theory of evolution

August 5, 2015

An Indiana University professor is part of an international team of biologists working to expand Darwin's theory of evolution to encompass factors that influence a species' growth and development beyond genetics—as well ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.