Mutant chicken gene linked to facial defects

"The chicken offers researchers unique advantages because the embryo develops in the egg, and all stages of development are available for analysis," says Mary Delany. (Credit: Nikol Lohr/Flickr)

Thousands of babies are born in the US each year with craniofacial defects, including cleft lips and palates, as well as more severe abnormalities of the face or head. New research on chicken genetics and biology are helping scientists understand the basis of these abnormalities in both birds and humans.

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The researchers focused on a mutation of the gene named talpid2, known to be associated with a number of congenital abnormalities, including limb malformations and cleft lip or palate.

They found that talpid2—like other limb and craniofacial mutations found in both humans and chickens—is related to the malfunction of “cilia,” tiny, hair-like structures on the surface of cells of the body.

Cilia play a vital role in passing along signals during development. When a gene mutation interferes with the normal structure and function of the cilia, it sets off a chain reaction of molecular miscues that result in physical abnormalities, in chickens or in people.

“Now that this new information is available, the talpid2 mutation can be expanded as a model for studying similar congenital abnormalities in humans including oral-facial defects, which affect many people around the world,” says Mary Delany, animal science professor at UC Davis.

Delany says that the findings also are significant for production of poultry and livestock, which are likewise vulnerable to genetic mutations that cause similar physical abnormalities.

In the chicken genome

The specialized genetic line of chickens used for this study is a member of a group of unique avian genetic resources maintained for decades by UC Davis.

“The chicken offers researchers unique advantages because the embryo develops in the egg, and all stages of development are available for analysis,” says Delany.

The study’s publication, in the journal Development, aligns with the tenth anniversary of the initial sequencing of the chicken genome.

“The National Institutes of Health and the US Department of Agriculture embarked on a partnership to fund sequencing of the chicken genome precisely because of the value of the chicken as a model organism for studying human health and its significance around the world as a source of food protein in the form of eggs and meat,” Delany says.

Additional researchers contributed to the study from the Cincinnati Children’s Hospital Medical Center; University of Maryland, Baltimore; Michigan State University; USDA-ARS in Michigan; Purdue University; and Miami University, Ohio.

The National Institutes of Health, the Cincinnati Children’s Research Foundation, the John and Joan Fiddyment Endowment, and the National Institute of Food and Agriculture through the National Animal Genome Research Support Program funded the study

Source: UC Davis