Associate Professor of Biology Tamara Davis Receives $300,000 NSF Grant to Fund Genetic Research

Posted June 12th, 2012 at 3:22 pm.


Bryn Mawr College Associate Professor of Biology Tamara Davis was recently awarded a National Science Foundation grant of nearly $300,000 to support her research in genomic imprinting.

Broadly understood, genomic imprinting is the phenomenon by which a subset of genes is expressed solely from one of the two parental alleles−that is, either the copy inherited from the mother or the copy inherited from the father.

“When imprinting occurs, only one of the alleles in a pair is expressed, meaning that it makes a protein or some other type of functional product. The other copy, even if it’s capable of doing so, doesn’t. That’s unusual because generally both copies we inherit are treated the same way in the cell. So for most genes, the two alleles are expressed at the same time, in the same cell type or at the same relative level,” explains Davis.

While only about 120 of the roughly 25,000 known mammalian genes have been identified as imprinted genes, they do have an important role.

“It turns out that a lot of imprinted genes are really important for growth and development in humans and other animals. If, for example, you don’t have imprinting and both copies of a certain gene are being expressed, you get an imbalance of growth-factor gene product that leads to developmental defects,” says Davis.

Developmental disorders in humans linked to imprinted genes not being expressed properly include Beckwith-Wiedemann Syndrome, Angleman Syndrome, and Prader-Willi Syndrome.

Higher rates of some of these disorders have been detected in children born through in vitro fertilization, which has led some researchers to believe that the process of IVF may somehow perturb the imprinting status of some genes.

Imprinting-linked disorders associated with in vitro fertilization are also an issue for the cattle industry.

“There’s something called ‘large-calf syndrome’ that’s been traced back to imprinting issues connected to in vitro fertilization,” says Davis.

Large-calf syndrome is an issue for the industry because cattle born with the disorder have higher rates of breathing difficulties, problems with suckling, and an increased chance of sudden death shortly after birth.

A number of cancer cells have also been shown to have disregulated imprinted genes.

“So in addition to the academic desire to better understand the biology at play, there are a lot of real-world implications to this research,” Davis says.

Davis and her students will be looking specifically at a process called DNA methylation using tissue from mice to better understand when DNA methylation is acquired at certain imprinted genes during development.

“If we can help zero in on the critical time period when DNA methylation is acquired, then that information could be used in future studies as we examine critical time points in development in order to help us understand when DNA appears to be sensitive to modification, such as during assisted reproduction or the manipulation of embryonic stem cells,” says Davis.

In addition to equipment and supplies, the grant will fund research opportunities for three Bryn Mawr students over the next three summers.

Students conducting research in the lab will attend weekly lab meetings, present their research to the Bryn Mawr community annually, and disseminate their data to the broader scientific community through publication in peer-reviewed journals and presentations at both international scientific conferences and undergraduate research symposia.

Since Davis’ arrival at Bryn Mawr in January 2000, she has had 39 undergraduate students work in her research lab. Of the students she has supervised, 18 have been co-authors on five of her publications. In the past 11 years, her students have regularly presented posters on their research at extramural undergraduate research symposia and international scientific conferences.

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