Natalay Kouprina of the US National Cancer Institute in Bethesda, Maryland, who is a part of the team that successfully created genetically engineered mice with an extra human artificial chromosome in their cells, told the Independent that it is the first time such an advanced form of a synthetic human chromosome built 'from scratch' has been shown to work in an animal model.She said that the point of creating the human artificial chromosome project is to develop a shuttle vector for gene delivery into human cells to study gene function in human cells.Kouprina said that potentially the new breakthrough has applications for gene therapy, for correction of gene deficiency in humans.She asserted that human artificial chromosomes are sometimes known as 'chromosome 47' as the normal complement of chromosomes in human cells is 46, explaining that the advantage in gene therapy is that the 47th chromosome doesn't interfere with the other 46 chromosomes, unlike conventional gene therapy where an extra gene is inserted often at random into the human genome.Kouprina said that conventional gene therapy uses vectors like viruses to insert genes into chromosomes, which can cause problems which do not happen with human artificial chromosomes because they do not interfere with other parts of the genome.She added that the idea is to take skin cells from a patient, turn them into stem cells and insert HACs into these stem cells with healthy copies of the disease gene. These cells, with the extra chromosome, can then be inserted back into the patient to treat the illness.Source: ANI