Scientists hope that the advances in the cloning process can bring back animals that are nearly extinct
Cloned bull named Got AP Photo/I.Lopez
Cloning envisioned. Dr. Hans Spemann (Germany) proposed an experiment to remove the nucleus from an unfertilized egg and replace it with the nucleus from a differentiated cell.
Structure of DNA (deoxyribonucleic acid) discovered by Francis C. Crick (U.K.) and James D. Watson (U.S.).
Dr. John B. Gurdon (U.K.) clones a frog by transplanting the intestinal cell of a tadpole into an enucleated frog egg, which develops into an adult frog.
First successful gene splicing (recombinant DNA) by Paul Berg and Stanley N. Cohen (U.S.). A major breakthrough in genetic engineering.
Birth of first child, conceived by in vitro (literally “in glass”) fertilization to Leslie Brown (U.K.).
U.S. Supreme Court rules that a genetically created new bacterium (a non-natural manmade microorganism) may be patented.
Dr. Steen M. Willadsen (Denmark) clones a lamb from a developing sheep embryo cell. His experiment is repeated by other scientists who clone a variety of animals.
Dr. Ned First (U.S.) clones calves from cells of early embryos.
Drs. Ian Wilmut and Keith Campbell (U.K.) create the world's first cloned sheep, Megan and Morag, from embryo cells.
Dr. Ian Wilmut and his team clone the world's the first sheep from adult cells. The lamb born in July 1996 is named Dolly.
Scientists at Oregon Regional Primate Research Center (U.S.) create first primates—two rhesus monkeys named Neti and Ditto—from DNA taken from cells of developing monkey embryos. They are not genetically identical because two different embryos were used.
A team led by Drs. Ian Wilmut and Keith Campbell (U.K.) create the first sheep with a human gene in every cell of its body. The genetically engineered lamb is named Polly.
Dr. Gerald Schatten (U.S.) leads a team of researchers who become the first to create a clone (Tetra, a rhesus monkey) by embryo splitting.
Dr. Xiangzhong Yang leads a U.S. experiment to clone calves from frozen cells taken from a Japanese bull. The experiment is successful and proves that cells can be stored for later cloning.
The first patents for cloning are given to the scientists who cloned Dolly, giving their company, Geron Bio-med, exclusive right to the technologies they used.
Japanese scientists clone a baby bull from a bull that was a clone itself, the first re-cloning case involving a large mammal.
Five piglets are cloned by a company the eventually wants to reproduce organs for humans.
Scientists at Advanced Cell Technology in Massachusetts clone human embryos for the first time.
President Bush limits federally funded human embryonic stem cell research to stem cell lines that have already been created.
A cat, called C.C. for “carbon copy” is cloned by a company that wants to go into business reproducing pets.
California becomes the first U.S. state to approve a law legalizing the therapeutic cloning of embryos.
Britain becomes the first country to issue research licences for human embryonic cloning to create stem cells. It specifies therapeutic, not reproductive, cloning.
Britain announces the first embryonic stem cell bank.
South Korea clones a dog named Snuppy. Dogs are considered particularly difficult to clone because of the complex reproductive biology.
South Korea announces that in 2005, cloned wolves are born. In Japan, a fourth-generation pig is cloned, proving that a mammal can be cloned for multiple generations.
Scientists in Spain are able to clone an extinct animal for the first time: the Pyrenean ibex, a subspecies of the Spanish ibex. When the last one died, scientists saved the skin in liquid nitrogen, preserving the DNA. In early 2009, scientists implant this ibex’s DNA into domestic goat eggs. The previously extinct Pyrenean ibex is born but lives for only seven minutes due to lung defects.
Dr. Nisar Ahmad Wani and his team clone the world’s first camel in Dubai, India. The camel, Injaz, ia cloned from the ovarian cells of a dead camel. Injaz is born to a surrogate mother. This is hailed as a genetic breakthrough for mammal cloning. (See 2015 for update on Injaz)
Scientists in Spain work for three years to achieve cloning of a bull, which culminates in the successful replication of Palencia, a prestigious fighting bull. On May 18, 2010, Got, the cloned calf is born through a surrogate Swiss milk cow and is an exact replica of his father. Animal activists are outraged that cloning is being used in the bullfighting industry.
A lab in Argentina becomes the first successful laboratory to create a transgenic cow. The use of human genes introduced during the cloning process means the cloned cow, Rosita ISA, will be able to produce human-like milk.
Scientists from Russia and Japan are attempting to bring the woolly mammoth out of extinction. A laboratory has been set up in Siberia, Russia. The goal is to take the DNA from a recently found thigh bone and introduce the DNA into an Asian elephant’s egg. Skepticism abounds in the larger scientific community because previous attempts to capture viable DNA from the frozen carcass have been unsuccessful.
A breakthrough in human cloning takes place in 2013 when scientist Shoukhrat Mitalipov and his colleagues are able to make advancements in stem cell cloning. Stem cells are extremely useful to the body because they have the ability to adapt and become whatever the body needs them to become. Mitalipov used "somatic cell nuclear transfer" to make human embryos that can be a source of embryonic stem cells.
Two cave lion cubs are found in Russia. Frozen more than 12,000 years ago, scientists hope to extract DNA from their soft tissue and use stem cell technology to create an embryo which will then be implanted in an African lion.
A team of scientists from the U.S., Germany, Italy, and Japan decide to clone the white rhino. Only two females remain of the species, and researchers plan to harvest their eggs, then use in vitro fertilization (IVF) and stem cell technology to create embryos that can be implanted into a surrogate rhino mother.