Professor of Genetics Scott Williams, PhD, of the Institute for Quantitative Biomedical Sciences (iQBS) at Dartmouth's Geisel School of Medicine, has made two novel discoveries: first, a person can have several DNA mutations in parts of their body, with their original DNA in the rest -- resulting in several different genotypes in one individual -- and second, some of the same genetic mutations occur in unrelated people. We think of each person's DNA as unique, so if an individual can have more than one genotype, this may alter our very concept of what it means to be a human, and impact how we think about using forensic or criminal DNA analysis, paternity testing, prenatal testing, or genetic screening for breast cancer risk, for example. Williams' surprising results indicate that genetic mutations do not always happen purely at random, as scientists have previously thought.
"We are in reality diverse beings in that a single person is genetically not a single entity -- to be philosophical in ways I do not yet understand -- what does it mean to be a person if we are variable within?" says Williams, the study's senior author, and founding Director of the Center for Integrative Biomedical Sciences in iQBS. "What makes you a person? Is it your memory? Your genes?" He continues, "We have always thought, 'your genome is your genome.' The data suggest that it is not completely true." If our human DNA changes, or mutates, in patterns, rather than randomly; if such mutations "match" among unrelated people; or if genetic changes happen only in part of the body of one individual, what does this mean for our understanding of what it means to be human?
How may it impact our medical care, cancer screening, or treatment of disease? We don't yet know, but ongoing research may help reveal the answers.
Kemo D. 7