Natasha Collins graduated Cornell in 2005. She was accepted to Yale medical school and planned to attend after spending time in Qatar to teach chemistry to college students, but was diagnosed with leukemia during the summer of 2006. Natasha has been bravely fighting the disease ever since with the support of her friends and loving family. Unfortunately, she now needs a bone marrow transplant to save her life.

Finding a compatible bone marrow donor requires a complex match of at least six different genes. About 30% of people who require a bone marrow transplant find a matching donor within their own family, because tissue types are inherited. The rest must be checked against a national bone marrow donor registry. About 90% of patients who find a match on the registry are of the same race as their potential donor.

For a person of Northern European descent in the United States, the chance of finding a suitable match is estimated to be at least 70%. However, for people of African or Caribbean heritage, the chance of a match could be less than 30%. For people like Natasha, who is a leukemia patient of mixed black and white heritage, the chances of finding a match may be even lower. A likely match may also be of mixed ethnicity, and such people are significantly underrepresented on the national donor list.

After no marrow donor has been found in the immediate family, a potential donor is likely to be a total stranger. However, as Milgram showed in his letter experiments, almost every person in the United States is connected with every other by a relatively small number of social links. Natasha and her family have enlisted the help of online social networking to increase her chances of finding a suitable donor match. Recently, Natasha’s brother Teddy created a group called Become a Hero on Facebook to encourage friends to register as marrow donors.

If we consider Granovetter’s theory on the “Strength of Weak Ties,” this strategy inherently makes sense. A person like Natasha, who attended a large, multicultural university like Cornell, would likely form her strongest friendships from her freshman living experience, classes, and activities. Many - or more likely, most - of her closest friends would not be of similar ethnic heritage, especially since she belongs to a statistically small minority. However, she may have a larger number of acquaintances with similar ethnic backgrounds that she met through friends, clubs and organizations. Furthermore, these acquaintances are likely to know an even larger number of other people with similar heritage. It might be possible to find a potential donor by following a few weak links in this network of acquaintances of mixed black/white ethnicity.

Natasha’s best chance of finding a donor match may be to tap this network using word-of-mouth and the power of online social networking tools. By spreading information and encouraging people to register as marrow donors, she can bridge the ethnic gap that hurts her chances of finding a donor on the national registry.

For more information, visit Natasha’s marrow donor page or the National Marrow Donor Program.