An unusual case illustrates how promiscuous DNA can be. It turns out we have a lot of DNA that isn’t our own Paternity tests are well known for producing some unexpected surprises, but the case involving a Washington man presents a new head-scratcher. After undergoing fertility treatments and having a son, the man and his partner were surprised when blood work showed that the boy couldn’t be related to the father. After two paternity tests showed the father only shared 10% of his child’s DNA, the parents feared the fertility clinic had inseminated the mother with another man’s sperm. The couple hired a lawyer, who wrote in to Barry Starr’s Ask a Geneticist blog. Starr, director of outreach activities at Stanford University’s Department of Genetics, suggested that the couple get a 23andMe analysis done. The consumer-based genetic testing company provides more detailed relationship and ancestry type genetic data—using hundreds of thousands of markers on the genome—than the dozen or so ma...
By Tané Tachyon You had probably heard that I had a miscarriage on 3/23, when I would have been about 14 1/2 weeks pregnant. It was like the miscarriage I had had seven years earlier, in terms of that there was nothing more recognizable than hunks of tissue, and in the amount of tissue and bleeding. It was unlike the miscarriage I had had seven years earlier, in that there was no cramping nor gush of amniotic fluid. There can be a lot of variation in these things depending on why the miscarriage occurs. I did not have any of the warning signs of infection resulting from an incomplete miscarriage, but went to the local women’s health center on 3/28 for a checkup. They thought everything looked fine (and complimented me a lot on my medical knowledge) but were concerned that my blood HCG levels were still at the full-blown pregnancy stage. All my subjective pregnancy symptoms (heartburn, fatigue, gagging, breast tenderness) were also continuing in full bloom. So I went back in for ...
Human chimeras are more common than you might expect. In Greek mythology, a chimera was a fire-breathing creature with physical traits of a lion, goat, and dragon. In human beings, a chimera is a person who has two totally different sets of DNA inside their body. It’s a bit less dramatic than a fire-breathing monster, sure, but it’s still pretty wild. Even wilder: Human chimeras aren’t the result of futuristic genetic tinkering. They can occur naturally, and some people don’t even know that they’ve doubled up on DNA. Here’s a quick guide to the ways a person can become a human chimera. It can happen after a bone marrow transplant Bone marrow is the tissue inside our bones that’s responsible for making white blood cells, red blood cells, and platelets. In bone marrow transplants, doctor uses chemotherapy or radiation to destroy all the recipient’s diseased bone marrow, then a donor’s healthy marrow is put in its place. The donor...