Why is my Mom a chimera?
A chimera is a creature from Greek mythology usually described as a monster containing the body parts of many different kinds of animals. Am I calling your Mom a monster though? Nope! But your biological mother is a chimera. Why?
Bite-Sized Science
In biological terms, a chimera is a person who has the DNA of multiple people in their bodies. Although we usually just think about our own DNA, women who have had a baby also carry their offspring’s DNA for decades after birth. During pregnancy, doctors can detect the tiny amounts of the baby’s DNA present in Mom’s blood and use it to determine the sex of the baby, and if they have the right amount of DNA (or chromosomes).
A Closer Look
During pregnancy, people have ~6% fetal DNA in their blood. Although after birth this number goes down, some fetal tissue remains behind. But why are they there? The current state of scientific discovery does not give a clear answer. Some research studies say these cells are helpful and could protect Mom against future disease. Other research studies say these cells are potentially harmful and could lead to more health problems.
Testing fetal DNA through a blood sample, a procedure called Non-Invasive Prenatal Testing is replacing more invasive and risky procedures like amniocentesis. The presence of fetal cells after birth also can bring comfort to individuals who’ve lost their baby from miscarriage, stillbirth, or complications after birth.
Suggestions for Teaching
Have students look up different studies that describe the health benefits or consequences of microchimerism. What research question would they like to ask?
Twins can also share each other’s DNA. Have students research the potential benefits of sharing DNA with a twin.
Have students research other examples of genetic microchimerism, such as during organ/tissue or transplant or blood transfusion.