Thread: Ask a Scientist
View Single Post
  #2122  
Old 28.02.2021, 18:50
marton's Avatar
marton marton is online now
Forum Legend
 
Join Date: May 2008
Location: Kt. Zürich
Posts: 10,100
Groaned at 446 Times in 384 Posts
Thanked 18,650 Times in 9,867 Posts
marton has a reputation beyond reputemarton has a reputation beyond reputemarton has a reputation beyond reputemarton has a reputation beyond reputemarton has a reputation beyond reputemarton has a reputation beyond repute
Re: Ask a Scientist

Quote:
View Post
…did you read all article you quoted?...
…see below I meant something else...

Reproductive cloning is a very inefficient technique and most cloned animal embryos cannot develop into healthy individuals. For instance, Dolly was the only clone to be born live out of a total of 277 cloned embryos. This very low efficiency, combined with safety concerns, presents a serious obstacle to the application of reproductive cloning.

Researchers have observed some adverse health effects in sheep and other mammals that have been cloned. These include an increase in birth size and a variety of defects in vital organs, such as the liver, brain and heart. Other consequences include premature aging and problems with the immune system. Another potential problem centres on the relative age of the cloned cell's chromosomes. As cells go through their normal rounds of division, the tips of the chromosomes, called telomeres, shrink. Over time, the telomeres become so short that the cell can no longer divide and, consequently, the cell dies. This is part of the natural aging process that seems to happen in all cell types. As a consequence, clones created from a cell taken from an adult might have chromosomes that are already shorter than normal, which may condemn the clones' cells to a shorter life span. Indeed, Dolly, who was cloned from the cell of a 6-year-old sheep, had chromosomes that were shorter than those of other sheep her age. Dolly died when she was six years old, about half the average sheep's 12-year lifespan.
You just posted a short excerpt
Read the whole article.
You even left out the last paragraph in your excerpt
Quote:
Two years later, researchers in Japan cloned eight calves from a single cow, but only four survived.

Besides cattle and sheep, other mammals that have been cloned from somatic cells include: cat, deer, dog, horse, mule, ox, rabbit and rat. In addition, a rhesus monkey has been cloned by embryo splitting.
Reply With Quote