Cloning of reporter shouldn't cause fear
OUHSC cloning of reporter shouldn't cause fear

By Jeff Raymond

Published: February 25, 2008

I have been cloned.

Now, before fear — or revulsion — grips you over the possibility of two of me running around, I should clarify: University of Oklahoma Health Sciences Center researchers cloned a gene from a cheek cell.

Some of the methods used in the simple cloning are similar to those used in more complex research and in clinical genetics testing, such as whether a newborn has cystic fibrosis.

The gene I had cloned helps recycle hemoglobin, which carries oxygen in the blood and contains iron. The gene produces a protein that keeps iron from building up.

Dr. Terrence L. Stull, Children's Medical Research Institute Patricia Price Browne Distinguished Chair and the organization's scientific director, has cloned the haptoglobin-producing gene before and now uses it to teach science to nonscientists.

When Stull began his career years ago, researchers had to manually determine the genetic code of a DNA sample. Now, it costs $12 and is done through the mail.

It's cheaper for Stull to have someone else sequence the DNA than to do it in his lab.

"It's still very magical for me, but it's pretty routine stuff now,” he said of the science behind the technique.

Whitby's staff then combined my gene with bacterial DNA, resulting in a harmless strain of E. coli that had my DNA in it.

After removing my DNA from its short-term bacterial home, Whitby sent it to have it sequenced — or the DNA alphabet determined. Once complete, the sequence is compared to others in a huge database to find matches.

The gene-cloning was successful.

Dr. John Mulvihill, Kimberly V. Talley Chair in Genetics at CMRI, said genetic testing is commonly used to diagnose cystic fibrosis. A mutation in a single gene causes the lung and digestive system disorder. If both parents carry the defective gene, there is a 1 in 4 chance their child will have cystic fibrosis.

Although physicians can often determine whether a baby has cystic fibrosis, Mulvihill's lab tests the borderline cases.

Neurofibromatosis is another disease caused by changes in a single gene. It affects about 1 in 3,000 babies and affects the growth of nerve cell tissue. Mulvihill's lab is one of only two nationwide that can make a diagnosis with certainty because of its experience sequencing the huge gene that causes the disease.

For that test, lab personnel cut up the gene, taken from a blood sample, into smaller pieces for the $1,800 test and compare them with the DNA sequence of a normal gene.

Mulvihill attributed much of the growth in genetic testing to the fact that scientists can now make large amounts of DNA.

"It has just made a world of difference,” he said.

Mulvihill feels strongly about making sure patients who receive diagnoses based on genetic tests are counseled on the tests' meaning and why they matter. Patient education needs to accompany technology from the beginning, he said.

Crime scene and paternity DNA testing involves analyzing seven to 13 DNA sequences.

"So if you combine 13 different areas each of which can be largely variable, then the exact probability of having the same pattern ... is zero,” he said.

Because children receive half their genetic material from each parent, a child will have similarities to his or her mother or father but not to a complete stranger.

Whitby said his lab's approach is similar to that of forensics labs.

"Much as you ask if this person committed that crime, we ask if this gene has committed that crime,” he said of whether a gene is responsible for a disease.

Comments