ECU scientist to discuss research on the genetics of twins through Earth & Sky network's live online chat

Dr. Charles Boklage, an East Carolina University geneticist, will be the featured scientist Oct. 8, on the Earth & Sky radio network's Edge of Discovery live online chat program. The live chat will be from 1 to 2 p.m. (EST) on www.earthsky.org.

Boklage, a professor in the Department of Pediatrics in the Brody School of Medicine and adjunct professor of biology at ECU, has studied the development and genetic make-up of twins for the past 20 years. Through his research, Boklage has discovered that one in every eight people who were born as a singleton started out as a twin in the womb. Boklage has also studied twins and their relationship between right- and left-handedness and their higher risk of birth defects or deformities.

A father of twin girls, Boklage is fascinated by the complexity of early human development and the concept that is sometimes referred to as the vanishing twin syndrome. The factors that cause one embryo to thrive while the other is absorbed into the lining of the uterus or when one embryo has a genetic flaw that triggers a spontaneous abortion are still unknown.

"For many twin conceptions, one of the embryos will not make it to the point of pregnancy recognition, which usually occurs around six weeks once a woman has missed her second consecutive menstrual cycle," Boklage said. "Only one in every 50 twin conceptions will arrive at birth as live twins."

The extensive use of fertility drugs coupled with women delaying pregnancy is also producing a marked increase in the number of twin conceptions and live births. Unlike single births, twins are more likely to be born prematurely and at a lower birth weight. These are some of the topics Boklage will cover during the online discussion.

According to the Centers for Disease Control, twins account for approximately two percent of all live births in the United States and an even higher percentage of birth-related problems. "The risk for low birthweight (LBW) among twins is seven times greater than among singletons," the CDC reported in 1997 following an assessment of twin births from 1980-1994. "In addition, twins account for 17 percent of all LBW infants and approximately 12 percent of all infant deaths."

With the expanded use of genetic and DNA testing, a new wrinkle in the human development mystery is surfacing-whether individuals born as singletons are carrying one set of genetic codes in their bodies or whether two embryos merged in the early stages of development to form a single person.

It's a concept that causes more headaches than the proverbial question, "which came first, the chicken or the egg?" Even the name of the concept -a chimera-sounds more at home on the Starship Enterprise than in a college classroom. Still, the concept of one person carrying one genetic code in their organs and a different code in their blood poses a multitude of wrinkles for law enforcement and paternity testing that rely heavily on DNA testing. It can even pose questions for organ transplants from family members.

Boklage includes the concept of chimeras in his genetics course and says it's a concept that many people have a hard time accepting.

"The egg is the largest and most complex human cell," Boklage said. "I'm certain that chimeras are far more common than we realize, and it's something that happens entirely by accident in normal, healthy peopleÉ. Most people don't want to think that these kinds of things even happen."

The Earth & Sky network is a daily science radio series broadcast on more than 950 commercial and public stations throughout the United States and through several international networks including Armed Forces Radio, World Radio Network and Voice of America. For more information, visit Earth & Sky online at www.earthsky.org.

The East Carolina University Division of Health Sciences comprises the Brody School of Medicine, the Schools of Nursing and Allied Health Sciences, and the William E. Laupus Health Sciences Library. The medical school is affiliated with University Health Systems of Eastern Carolina in Greenville, N.C. 10/03/03

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