Here's why:
* Mitochondrial DNA: Mitochondria have their own DNA, separate from the nuclear DNA in the cell's nucleus. This mitochondrial DNA (mtDNA) is inherited solely from the mother.
* Clonal Mismatch: When an egg is used for cloning, the nuclear DNA is replaced with the DNA from the individual being cloned. However, the mitochondrial DNA in the egg remains unchanged. This means that the resulting clone will have the mitochondrial DNA of the egg donor, not the person being cloned. This creates a mismatch in the DNA, which could lead to developmental problems or even be fatal.
While this doesn't technically make cloning impossible, it makes it extremely challenging and ethically problematic. The resulting clone would not be a perfect genetic copy of the original individual due to the different mitochondrial DNA.
It's important to note that this is one of many factors that make human cloning extremely difficult, if not impossible, with current technology. There are also ethical and societal concerns that make human cloning a controversial topic.
