Two enzymes are used to produce recombinant plasmids. Restriction enzymes cut DNA at specific 4- to 8-bp sequences, often leaving self-complementary single-stranded tails (sticky ends). These enzymes are used to cut long DNA molecules into multiple restriction fragments and to cut a plasmid vector at a single site.

Because the risks associated with reproductive cloning in humans introduce a very high likelihood of loss of life, the process is considered unethical. There are other philosophical issues that also have been raised concerning the nature of reproduction and human identity that reproductive cloning might violate.

There is no federal law prohibiting human cloning; as of today, federal laws and regulations only address funding and other issues indirectly connected to cloning. At the state level, however, there are laws directly prohibiting or explicitly permitting different forms of cloning.

Scientists have found potentially definitive evidence that cloning is far too unsafe to be used in human reproduction, should it ever be viewed as ethically acceptable in the future.

The clones, them- selves, however, suffer the most serious problems: They are much more likely than other animals to be miscarried, have birth defects, develop serious illnesses, and die prematurely.

Dolly was cloned from a cell taken from the mammary gland of a six-year-old Finn Dorset sheep and an egg cell taken from a Scottish Blackface sheep. Because Dolly’s DNA came from a mammary gland cell, she was named after the country singer Dolly Parton. Learn more about cloning with our cloning FAQs.

Not the usual sperm + egg She lived to six and a half years, when she was eventually put down after a contagious disease spread through her flock, infecting cloned and normally reproduced sheep alike. Her life wasn’t unusual; it’s her origin that made her unique.

No, not at all. A clone produces offspring by sexual reproduction just like any other animal. A farmer or breeder can use natural mating or any other assisted reproductive technology, such as artificial insemination or in vitro fertilization to breed clones, just as they do for other farm animals.

six and a half years

“Clones are genetically identical individuals,” says Harry Griffin, PhD. “Twins are clones.” Griffin is assistant director of the Roslin Institute — the lab in Edinburgh, Scotland, where Dolly the cloned sheep was created in 1997.

Could we clone a dinosaur? The dinosaurs went extinct around 66 million years ago and with so much time having passed it is very unlikely that any dinosaur DNA would remain today. While dinosaur bones can survive for millions of years, dinosaur DNA almost certainly does not.