The question of whether a clone possesses a belly button, or navel, often arises from scientifically inaccurate depictions in movies and fiction. These narratives frequently show clones being grown fully formed in sterile tanks or artificial wombs, implying they bypass normal development. The definitive biological answer is straightforward: yes, a mammalian clone, created using current technology, will have a belly button just like any naturally conceived individual.
The Biological Origin of the Navel
The navel is not a genetic feature but rather a physical scar found on all placental mammals. It marks the spot where the umbilical cord was once attached to the developing fetus’s abdomen. This cord is a temporary, necessary lifeline for the developing organism during its time in the womb.
The umbilical cord functions as a biological conduit, connecting the fetus to the placenta, an organ formed within the uterus. This connection is fundamental for sustaining life. The cord transports oxygen and nutrient-rich blood from the maternal circulation to the fetus. Conversely, it carries waste-filled blood back to the placenta to be filtered out by the mother’s body.
Once the organism is born, the umbilical cord is severed, as its function has been replaced by the newborn’s independent respiratory and digestive systems. The small stump of tissue that remains on the abdomen dries up and eventually falls off a few days after birth. This healing process leaves behind the permanent scar known as the navel, or belly button.
The Necessity of Gestation in Mammalian Cloning
The most successful method for creating a mammalian clone is Somatic Cell Nuclear Transfer (SCNT), famously used to create Dolly the Sheep. This technique begins by taking the nucleus, which contains the full genetic blueprint, from a somatic cell (a body cell) of the animal to be cloned. That nucleus is then inserted into an unfertilized egg cell from which the original nucleus has already been removed.
After the transfer, the reconstructed egg is stimulated, often with an electric pulse, to begin dividing as if it had been fertilized. This process creates a viable, early-stage embryo that is genetically identical to the donor organism. This microscopic embryo is not yet a fully developed animal; it is merely a cluster of cells.
To progress into a fully developed mammal, the clone requires a complete and natural gestation period. The SCNT-derived embryo must be implanted into the uterus of a surrogate mother of the same species. There is no current technology that can fully replicate the complex biological support system of a host uterus, meaning the clone must develop inside a living animal.
The Definitive Answer: Why Clones Have Belly Buttons
The synthesis of these biological facts provides the conclusive answer. Since the cloned embryo must undergo full gestation within a surrogate mother’s uterus, it requires the same biological support system as a naturally conceived fetus. This support system includes the formation of a placenta and the development of an umbilical cord to connect the clone to the placenta.
The cord is the physical manifestation of the clone’s reliance on the surrogate mother for oxygen and nutrients throughout its prenatal development. When the clone is delivered, the umbilical cord is cut, exactly as it is for a non-cloned animal. This severs the physical connection between the newborn and the placenta, leaving the remnant stump.
The healing of the umbilical stump results in the formation of the navel, a scar that all placental mammals share, regardless of their genetic origin. Dolly the Sheep, the world’s first mammal cloned from an adult cell, was carried to term by a surrogate mother and had a belly button. The existence of the navel confirms that the clone completed its development in a biological host, debunking the science-fiction concept of clones being grown in tanks.