Not only cells; we may soon be able to have our own organs grown in a nonhuman host , ready to be transplanted when needed. If Dolly was responsible for unleashing the events that culminate with new methods of making fully compatible cells and organs, then her legacy would be to improve the health of practically all human beings on this planet.
And yet, I am convinced that there are even better things to come. In the winter of , I found myself driving on the wrong side of the road through the Nottingham countryside. Keith was a smart, fun, loving friend who, along with Ian Wilmut and colleagues at the Roslin Institute , had brought us Dolly 15 years earlier.
We had met at a conference in the early s, when we were both budding scientists playing around with cloning, Keith with sheep, me with cows. An extrovert by nature, he quickly dazzled me with his wit, self-deprecating humor and nonstop chat, all delivered in a thick West Midlands accent. Our friendship that began then continued until his death. When I knocked at the door of his quaint farmhouse, my plan was to stay just a few minutes, pay my respects to his wife and leave.
Five hours and several Guinnesses later, I left feeling grateful. See, when Dolly was cloned, she was created using a cell from a six-year-old sheep. And she died at age six and a half , a premature death for a breed that lives an average of nine years or more. OTOH, the human germline eggs and sperm can't have mosaicism, since they are single-celled. Embryos can have it, but if try to modify a pluricellular human embryo, you will probably face a huge opposition from almost everyone out there ethicists, politicians, christians Antonio: This is the best answer I have received in a commentary field.
I asked myself this question about if our germ cells could have mosaicism, because as you write single cells cant have it, I thought. But doctors use the word germ line mosaicism which is misleading. All children born with congenital heart failure have mosaicism and I guess that its the cause of the birth defect.
When it comes to the opposition from bioethicists and other - we have to push hard forward. Biotech as an industry have to grow strong as it becomes an unstoppable force. I have all my money in BT for that reason. Yes, as Wikipedia says, mosaicism is when an organism has different genomes in different cells of his body.
It doesn't need to be detrimental. Post a comment; thoughtful, considered opinions are valued. New comments can be edited for a few minutes following submission. Comments incorporating ad hominem attacks, advertising, and other forms of inappropriate behavior are likely to be deleted. Note that there is a comment feed for those who like to keep up with conversations.
By checking, I consent to the storage and handling of my data. See the privacy policy and terms and conditions for details. Fight Aging! Antonio: Thanks. Im not educated, but have a basic understanding. The clones had readings between and millimeters of mercury, compared with mm Hg for the controls.
When given increasingly high doses of a hormone that narrowed their blood vessels, all of the sheep saw their blood pressure rise by a similar amount, according to the study. The conventional sheep had a lower resting heart rate — 76 beats per minute, compared with 91 to 92 for the clones — but the clones were still within the normal range for sheep of their age, the researchers noted.
To test whether the animals were susceptible to diabetes, the researchers allowed them to gorge on hay for 28 weeks. All of the sheep had fasting blood sugar levels within the normal range. The clones and the controls got similar scores for insulin sensitivity, but the clones fared worse in a glucose challenge. After the four Dolly-like clones were put on a diet, their insulin sensitivity improved.
The researchers took this as a sign that body fat — not age — was responsible for their diabetic tendencies. This was a topic of particular concern because Dolly was treated for osteoarthritis starting around the age of 5. Two of the 13 clones were judged to have an abnormal gait, though the differences were minor. All the cloned sheep had mild osteoarthritis in the hips, and most had it in their knees. So when scientists working at the Roslin Institute in Scotland produced Dolly, the only lamb born from attempts, it was a major news story around the world.
To produce Dolly, the scientists used the nucleus of an udder cell from a six-year-old Finn Dorset white sheep. The nucleus contains nearly all the cell's genes. Then they injected the cell into an unfertilised egg cell which had had its nucleus removed, and made the cells fuse by using electrical pulses. The unfertilised egg cell came from a Scottish Blackface ewe. When the scientists had managed to fuse the nucleus from the adult white sheep cell with the egg cell from the black-faced sheep, they needed to make sure that the resulting cell would develop into an embryo.
They cultured it for six or seven days to see if it divided and developed normally, before implanting it into a surrogate mother, another Scottish Blackface ewe. Dolly had a white face. From cell fusions, 29 early embryos developed and were implanted into 13 surrogate mothers. But only one pregnancy went to full term, and the 6. The main reason that the scientists at Roslin wanted to be able to clone sheep and other large animals was connected with their research aimed at producing medicines in the milk of such animals.
Researchers have managed to transfer human genes that produce useful proteins into sheep and cows, so that they can produce, for instance, the blood clotting agent factor IX to treat haemophilia or alphaantitrypsin to treat cystic fibrosis and other lung conditions. Cloned animals could also be developed that would produce human antibodies against infectious diseases and even cancers.
If this technique can be applied to mammalian cells and the cells cultured to produce cloned animals, these could then breed conventionally to form flocks of genetically engineered animals all producing medicines in their milk.
There are other medical and scientific reasons for the interest in cloning. It is already being used alongside genetic techniques in the development of animal organs for transplant into humans xenotransplantation. Combining such genetic techniques with cloning of pigs achieved for the first time in March would lead to a reliable supply of suitable donor organs. However, there are still worries about virus transmission.
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