What is Cloning?
[3.4]-Strawberries are known for cloning asexually. Ferns produce asexually as well.
Cloning has been occurring in nature since the beginning of time. Asexual reproduction is a form of cloning, as it lacks the "union of sex cells" [3.1]. Instead these plants reproduce by cloning themselves. Protests and bacteria, and other single celled organisms reproduce, asexually, as well as many types of plants. Strawberries are one of the most common examples. Identical twins are also an example of cloning occurring naturally.
Cloning animals is a relatively simple, but often difficult process. The success rate of the initial process is very low and numbers of actual births are even lower. Basically, there are two ways to clone an organism: Artificial Embryo Twinning and Somatic Cell Nuclear Transfer, or commonly known as, SCNT. SCNT is the most commonly used method now, as it gained popularity after the cloning of Dolly in 1996 [3.2].
[3.6]-Identical twins are an example of cloning in nature. The twins shared the same genetics, but have different personalities.
-
An egg cell is first cultured from a donor. The donor's DNA has to then be replaced with the DNA taken from the skin cells of the animal to be cloned.
-
The cell divides and grows into an embryo while still in a petri dish in a specially regulated laboratory. Many embryos are not able to fully develop to this stage.
-
If the embryo does develop correctly, it is then implanted into the uterus of a surrogate mother. At this point, even embryos that have developed to the advanced stage still have a difficult process ahead. Miscarriage of the embryo is very common because of the unnatural process.
-
Even the offspring that are born still face potentially life-threating health issues and abnormalities. The success rate is about 2%, but scientists are working to improve the odds [3.2]
[3.5]-Here is a diagram of the process. SCNT is used on most animals cloned today. It was the same process that helped create Dolly.
The Process: SCNT
What is the Future for Cloning?
Cloning has come a long ways since Dolly the Sheep was first cloned, but we still have a lot to uncover. In the last decade, scientists have started to clone endangered species and champion racehorses. They have even resurrected an extinct species. There are many new opportunities that scientists hope to uncover, but first they have to conquer a few problems. Primarily, they need to figure out how to increase the success rate of clones. With further research and hard work, animal cloning could skyrocket. But what is the big deal about cloning? And how did it start? Click below to find out.
[3.3]-Dolly with Professor Ian Wilmut from Roslin Institute in Scotland.