Genome Transplantation and the Creation of Synthetic Genomes

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Genome Transplantation and Synthetic Genome

We are familiar with kidney, heart, and lung transplants where whole organs are transplanted from a donor to a recipient, but transplantation technology can also take place at the genetic level as it is now entirely possible to transplant a complete set of genetic instructions from one organism into another. The recipient is phenotypically and genetically identical to the donor. The proof of principle of this technology was demonstrated in 2007 by scientists from the J. Craig Venter Institute in Rockville, Maryland.

Their research was conducted on two species of bacteria - Mycoplasma mycoides Large Colony (LC) and Mycoplasma capricolum. The LC chromosome was isolated and stripped of proteins, leaving naked DNA, which was the then transplanted into Mycoplasma capricolum cells. After several generations of cell division the recipient M. capricolum bacteria’s own genome had disappeared and was completely replaced by the M. mycoides DNA; it also took on the phenotypic traits of the donor.

Such technology could pave the way for synthetic life forms which could be involved in the production of clean fuels. Venter and colleagues are attempting to create artificial forms of life by stitching together chromosomes, DNA, and proteins and kick start them into life. Their work on the mycoplasmas demonstrated that it is possible to transfer a complete set of genetic instructions into an organism.

Genome Transplantation and Diseases

In additional genome transplantation studies scientists have been able to transplant an entire complement of nuclear DNA into an enucleated egg to create rhesus monkeys free from mitochondrial diseases. Mitochondria are found in the cytoplasm; they are the cell’s chief energy packs and they possess their own DNA. It would be too cumbersome to correct genetic faults in these tiny organelles, but they could be ignored.

Mitochondrial DNA is passed from a mother to her child via her eggs. Genetic faults could be ignored by extracting nuclear DNA from an egg with mitochondrial faults and implanting it into a healthy egg that has been stripped of its nuclear DNA. This genome transplantation technique has not been carried out in humans as it is far too early in the research process, but it has been used to successfully create healthy twin rhesus monkeys.