Today, obstacles to germ line engineering are practical, not theoretical. Scientists have the ability to add desired genes - snapping gene cassettes onto artificial chromosomes and injecting the chromosomes into newly fertilised eggs. Because every cell in the body is a descendant of that first fertilised egg, every cell would have a copy of the artificial chromosome once inserted.That is pretty cool that they can create artificial chromosomes and insert them into germ cells. I wonder what happens to the children of someone who has an extra chromosome?
Artificial chromosomes, even human artificial chromosomes, have already been created and patented, the scientists reported, and companies have sprung up to exploit the technology. Dr. Leroy Hood, chairman of the department of molecular biotechnology at the University of Washington in Seattle, said he has now developed a way to create an entire custom chromosome on a computer chip containing DNA.
Scientists at the meeting spoke quite seriously about extending the human life span with cassettes of anti-ageing genes. They also envisioned adding cassettes of anti-cancer genes and genes that would confer resistance to the AIDS virus.
Previously, researchers at Chromos Molecular Systems of Burnaby in British Columbia, Canada, used artificial chromosomes to add an extra gene to cells grown in the lab, and showed that the gene functioned when the cells were transplanted into mice. Now, Oshimura has actually corrected a genetic defect in stem cells.
Oshimura's team worked with stem cells from the testes of new-born mice in which the so-called P53 gene had been knocked out - P53 makes a protein that prevents tumour growth. Adding an artificial chromosome carrying a copy of P53 restored production of the protein in the stem cells, and activated another gene that is normally controlled by P53.
At the same meeting, Chromos announced that its researchers have inserted artificial chromosomes into human embryonic stem cells. Company vice-president Harry Lebedur claims that Chromos's chromosomes have the advantage that they can be more easily purified from the cell cultures in which they are grown and can be transferred to stem cells with greater efficiency.
via The Guardian