BREAKING DOWN THE SCIENCE & SCRUTINY
“World’s First Three-Parent Baby” made headlines in publications ranging fromNature to CNN last week. This human interest story is of a baby boy born in Mexico with genetic material from three different parents, achieved by a technique known as three-parent in vitro fertilization (TPIVF). In this issue, we will explain why TPIVF is used and examine the science—and scrutiny—surrounding this controversial baby-making method.
REPLACING MITOCHONDRIAL DNA IN IVF
The rationale behind TPIVF lies with mitochondria—what many of us remember from high school biology as the “powerhouse” of a cell. Recall mitochondria are the organelles that convert glucose into the energy our cells use to do work. What you may not remember is mitochondria have their own DNA that is inherited maternally. When an egg is fertilized, the mitochondria from the egg get passed on in subsequent rounds of cell division, becoming a part of every cell in the developing baby. A woman with defective mitochondrial DNA passes this trait onto her child. However, with the advent of TPIVF, these mutations can be weeded out of a family’s genetic landscape.During TPIVF the nuclear DNA is removed from the egg of the afflicted mother. This nuclear DNA is transferred into a donor egg whose own nuclear DNA has been removed, but whose mitochondrial DNA remains intact. The resulting donor egg is implanted into the prospective mother, and with fingers crossed, that donor egg (once fertilized with a sperm) develops into a healthy baby. The resulting child has DNA from two different women and one man.Read More