FRIDAY, Oct. 10, 2003 (HealthDayNews) -- The genes that let all mammals, including humans, control facial movement have been identified in research with mice by University of Utah scientists.
In mice, these genes ensure that nerves develop in the correct part of the brain so the rodents can move their eyeballs, wiggle their whiskers, blink their eyelids and pull back their ears.
Since these genes are common to all mammals, they likely help humans control facial expressions such as smiles and frowns, the scientists report.
"In this study we looked at what nerves are made in a particular part of the brain, the hindbrain," geneticist Mario Capecchi, professor and co-chairman of human genetics, says in a prepared statement.
"We see that in certain parts of the hindbrain, the embryo makes nerves that innervate the facial muscles, and in another part of the hindbrain, the embryo makes nerves that innervate eye movement," Capecchi says.
The study will appear in the Nov. 1 issue of Development.
In their study, Capecchi and his colleagues found that when they crippled two specific genes, mice embryos failed to develop nerves that normally connect to one of six sets of muscles controlling eyeball movement.
When the researchers disabled other genes, the mice embryos developed an extra set of nerve fibers that control facial muscles.
Understanding the processes that create specific nerve cells in developing embryos may eventually help scientists identify the causes of various diseases.
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