The future of cloning
AUSTRALIA’S laws on stem cells and human cloning are under review. A committee headed by former Federal Court Justice John Lockhart has called for public submissions 9 September. So where’s the fervent public debate?
Our laws currently ban any form of human cloning. Cloning a human being—so-called reproductive cloning—is clearly unethical, not least because it would produce a very sick individual. But cloning some cells from a person—so-called therapeutic cloning—is a different kettle of fish.
To understand the potential of therapeutic cloning, let’s indulge in a little future gazing. The year is 2020. The place is Seoul, South Korea—the world capital of “Regenerative Medicine.”
Three-year-old Emma has juvenile diabetes—caused deterioration of the islet cells which produce insulin in her pancreas. Twenty years ago, she would have been treated with insulin injections. But they didn’t always halt the blindness or kidney failure that came with the disease. Sometimes adults with Emma’s condition were lucky enough to get an islet graft from a donated pancreas, but then they had to take anti-rejection drugs for the rest of their lives—not advisable for kids.
Now, in 2020, Emma and her mum have made the trip from Melbourne to receive the treatment for which the Seoul clinic is famous. Emma has skin cells scraped from the side of her cheek. Meanwhile her mother, after treatment with hormones, has 10 eggs harvested from her swollen ovary.
In the lab, a steady-handed technician, wielding two fine needles under a microscope, plucks out the dark round nucleus from one of Emma’s skin cells. He inserts it into one of her mother’s eggs, from which the nucleus has been removed. Emma’s skin nucleus carried her genetic blueprint. Now inside her mother’s egg, it will start multiplying forming an embryo that is a clone of Emma.
After the embryo has divided about seven times, forming a hollow ball of about 100 cells, the technician will remove a clump of them that nestle in the interior. This clump will give rise to embryonic stem cells—biological gold. Embryonic stem cells multiply endlessly to produce the large numbers of cells needed for a graft, and they have the potential to mature into any tissue of the body. In this case, the stem cells will be matured into islet cells which, when grafted into Emma’s pancreas, will cure her diabetes. And, because the graft is made up of Emma’s own cells, it will not need to be accompanied deadly immune-suppressing drugs.
In the bone marrow section of the clinic, we find 30-year-old Josh. He has leukaemia. His bone marrow is about to be destroyed to kill off the cancer cells, but this cannot be done until he has a replacement graft of bone marrow cells. Twenty years ago people often died waiting for a matching donor, or died from a graft that wasn’t a good enough match. Josh is at the clinic to generate his own matching graft. The starting source, as for Emma, is his skin cells. This time, it is his girlfriend who is donating the eggs. Josh’s cloned embryo will again provide the embryonic stem cells, but this time the stem cells will go through a different maturation process, to produce primitive bone marrow cells, not islets.
Five-year-old Peter is at the clinic too. He has Falconi’s anaemia, a blood disease caused the loss of a single gene. Before technicians make up his bone marrow graft, they will replace the missing gene in his embryonic stem cells. Then, they will multiply them, and instruct them to mature as bone marrow cells.
In the neurology section we meet Mary, a 55-year-old with Parkinson’s disease, and her niece who is donating the eggs. Mary’s embryonic stem cells will be matured into dopamine-producing brain cells. These will be grafted into her brain to replace the cells that died off and caused her disease.
Back in Australia in 2020, things have changed dramatically for patients with motor neuron diseases, such as ALS or transverse myelitis. These conditions strike out of the blue killing off motor neurons. In the worst cases, patients progressively lose the ability to walk, talk, eat and breathe. Twenty years back, no-one knew how to halt the death of the neurons, because there was no way to study the disease. But in Korea they used therapeutic cloning to make embryonic stem cells from people with these diseases. Those cells were matured into motor neurons, which researchers employed as “model patients” in their studies. Korean drug companies used these cells to screen drugs, and found a compound that halts the death of the motor neurons. Now these diseases are no longer a death sentence.
This futurology is not fanciful. In 2002 and 2003, researchers carried out these exact therapeutic cloning techniques in mice with Parkinson’s disease and genetic blood diseases. They cured the mice.
In 2005, using drug screens, researchers found a compound that might help save motor neurons in kids with Spinal Muscular Atrophy—a disease that kills motor neurons in new born babies. Trouble is, they didn’t have the real, affected cells. For a drug screen you need cells that multiply readily; the best thing they could get were mouse brain cancer cells. With therapeutic cloning, they could have tested their drugs on motor neurons derived from the skin cells of sick kids.
Opponents of this future scenario claim that therapeutic cloning is unnecessary because adult stem cells, which we carry in some of our organs, will provide all the same benefits. I wonder how they know that. Because if there is anything we have learned from the progress of science, it is that, like football, we don’t know how to pick winners. As historian Daniel Boorstin put it, “ the greatest obstacle to discovery is not ignorance, it is the illusion of knowledge”.
Elizabeth Finkel is a Melbourne scientist, writer and author of Stem Cells – controversy at the Frontiers of Science.