Talk

Right on the tails of my last post comes ground-breaking news about identical twins: they don’t actually have identical genetics! (Darn close, but not 100% identical.)

A study by University of Alabama, Birmingham researchers challenges the long-held belief that identical twins have identical genetics. They compared the DNA of sets of twins and discovered significant copy number variation (or CNV).

…[S]ubstantial chunks of DNA sequences were missing, doubled or reversed in one of the two twins. Having chunks of DNA sequences shifted around or missing is a common genetic mutation. When first discovered, scientists thought it was inconsequential. Often it is, but researchers are beginning to learn that sometimes CNV can be a major factor in developing a disease. (more…)

I’ve got twins on my mother’s side and twins on my father’s side, too. On my mother’s side, they seem to appear every other generation, so the joke among my cousins is “which one of us will have the twins?”

Whether twins really do run in families or whether this is an old wives’ tale is a question many people ask. Senior genetic counselor Lisa Kessler, just answered that over at MedHelp’s genetic forum, where she is the moderator.

She explains that having identical twins is not typically something that runs in families, butBirth control and family planning
Choosing a primary care provider
Ewing�s sarcoma
Family troubles - resources having fraternal twins does — and it happens more frequently after the second pregnancy. Interestingly, this only applies to a history of twins on the woman’s side of the family. A history of twins on the father’s side doesn’t increase the chance of having twins.

So now we know. And now it’s up to my cousins to pass on the family tradition of twins!