Gaby
Recent research shows that a fetus tries to grab as many nutrients as possible from the mother during pregnancy. Unique ‘greedy genes’ inherited from the father help drive that push. Those genes can make the fetus influence the mother’s metabolism to maximize nutrient intake.
Everything Under Control
A pregnant woman’s body has to nourish the fetus while also protecting her own health. But if the fetus grows too large, delivery can become complicated. For that reason, the mother’s genes usually put limits on fetal growth.
As Dr. Miguel Constancia points out, some of the father’s genes act ‘greedy’ and ‘selfish.’ They shift maternal resources toward the fetus, allowing it to grow larger and potentially more viable. This research explains how paternally inherited genes in the placenta—a temporary organ that develops during pregnancy to nourish the fetus—can influence the mother’s metabolism from a distance.
The Mechanism of the Father’s ‘Greedy’ Gene
To probe this mechanism, researchers ran an experiment in which they removed the Igf2 gene from the placentas of pregnant mice. That gene is essential for proper fetal growth and tissue development.
The absence of Igf2 reduced release of an insulin-like growth factor protein that helps regulate glucose production. It also altered hormones that control insulin release from the pancreas and that affect liver activity. In short, a single placental gene changed the mother’s metabolism.
As the study’s lead author, Dr. Jorge Lopez-Tello, explains, when the father’s Igf2 function is turned off in placental signaling cells, the mother doesn’t produce enough glucose and lipids in her bloodstream. As a result, the fetus doesn’t receive enough of those nutrients and its growth is stunted.
The researchers say that disruptions to Igf2 can lead to abnormal growth—either too large or too small. Mice born to mothers whose placentas lacked Igf2 later showed signs of diabetes and developed obesity as they grew.
These findings highlight Igf2’s vital role in moving nutrients from mother to fetus and in shaping offspring health.
On the Path to Further Discoveries
The relationship between mother and offspring in mammals mixes cooperation with conflict. The fetus has evolved ways to tweak maternal physiology to increase nutrient transfer across the placenta, while maternal genes tend to limit that transfer. Many of the underlying mechanisms are still unclear.
So far, research suggests that Igf2 helps control protein synthesis and cellular energy balance. Losing Igf2 may also have long-term effects on offspring metabolism in adulthood.
According to Interesting Engineering, the research team plans to keep studying this system. They are investigating how Igf2 alters placental hormones and whether changes in those hormones’ chemistry could improve health outcomes for both mother and fetus.
