somatic cell nuclear transfer

Dolly at 20

Twenty years ago today on February 22, 1997,  Ian Wilmut, Keith Campbell and colleagues at the Roslin Institute, announced the existence of a 7 month old sheep named Dolly, the product of cloning.  She was cloned using and adult cell and born on July, 5, 1996 and raised under the auspices of the UK Ministry of Agriculture and Scottish company PPL Therapeutics.  A Dorset Finn sheep, Dolly lived for six and half years before she was euthanized due to illness.  Dolly was created with a process called somatic cell nuclear transfer, in which a donor cell (in this case and adult cell from another sheep) has the nucleus removed that is then transfered into an unfertilized egg cell (an oocyte) which in turn has had its cell nucleus removed to make way for the donor nucleus.  The host cell is then stimulated and implanted into a host sheep for gestation.  Although other animals had been cloned before Dolly, Dolly is celebrated as the first ‘clone’ because her donor cell came from an adult cell. 

The word clone entered English as a noun used in botany in 1903 from the Ancient Greek word klon (κλον) meaning a twig or spray, related to klados (κλαδος) meaning a sprout, young offshoot, branch.  Botanists used the word to describe the results of the techique of grafting a shoot of one plant or tree onto another.  The word clone (verb) wasn’t used until 1959, and it wasn’t until the 1970s that clone was used in connnection with animals and humans.  Since Dolly, scientists have successfully cloned many other animals, including pigs, horses, goats, and deer.  

Image of ‘v’ graft courtesy ghadjikyriacou, via flickr, used with permission under a Creative Commons 3.0 license.

anonymous asked:

so i know there was some kind of agreement among scientists saying though they COULD clone humans, they won't. but, how does that work? couldn't someone just do it anyway?

It could happen.

I’m not familiar with an agreement among scientists not to clone humans, but there are reasons not to. Scientists do clone human tissue (therapeutic cloning), but probably no one has succeeded in reproductive human cloning–ie, making a human baby with 100% a donor’s DNA, or somatic-cell nuclear transfer. 

(Reader poll: Do I still have to mention Raelians when I talk about human cloning? Or can we all just assume that they lied when they said they had successfully cloned a person and now we can all forget about it?)

Wikipedia has a list of laws about human cloning, although the US section needs to be updated. Here’s a good article called What Ever Happened to Cloning? published in August 2016.

Humans and primates are very difficult to clone and there doesn’t seem to be a market incentive to do it. Furthermore, there would be some public backlash to overcome.  Some criticisms of human reproductive cloning are practical (the cost, difficulty, and high chances that something could go wrong) and some are more philosophical (playing God) and some are plain science fiction (“we might accidentally start harvesting clones for organs.”)

Biology Side of Tumblr Tackles Chapter 85

(( As some of you may know, I’m currently an Environmental Public Health major with a Biology minor. Genetics is my jam, so let me just dissect this most recent chapter and all the technological mumbo jumbo in it for a bit.

This long-ass post has been brought to you by trying to avoid writing a paper and studying for finals.

Keep reading

Scientists Sequence a Full Mammoth Genome

Beth Shapiro, author of How to Clone a Mammoth, acknowledges that scientists will never clone a mammoth. But we might be able to bring them back other ways. But she also says we shouldn’t. 

There have been many attempts to decode the mammoth’s genes, but April 2015 saw the first successful complete mammoth genome sequencing. While this cannot lead to cloning in the strict sense of the word (somatic cell nuclear transfer requires a living cell from the donor species), it may be the next step in bringing the species back. 

With parts of the mammoth genome, we may be able to determine what genes separate the mammoth from an Asian elephant. Scientists may be able to edit the genes of an elephant to make it hairier, fatter, and with hemoglobins making its blood more suitable to cold environments. However, while this is a step in the direction of de-extinction, there are many more technical and ethical hurdles to overcome before there is a chance of reviving the mammoth.

Somatic Cell Nuclear Transfer (SCNT)

A process used to produce clones. Woah.

The method is to create a genetic copy of an individual, or clone.

Firstly, to take it apart, a Somatic Cell is a cell that contains two complete sets of chromosomes. This is essentially any cell in your body that isn’t a sperm or egg. Because sperm and eggs are “two sets of a whole” they only have one complete set of chromosomes.

When we use the term Nuclear here, we’re not talking about an explosion. It’s the nucleus of a cell, which is sort of like the cells brain. It contains all the genetic information and code that cells need to make an organism, also known as good old DNA.

Transfer of course means to move from one place to another.

So how it works is you take a somatic cell from one organism, let’s say a person, and you remove its nucleus, then insert the nucleus into an egg cell from another person, but the egg cell has to have had its nucleus removed.

So you’re transferring the nucleus of a somatic cell to an egg cell, without the nucleus.


So what does it have to do with cloning?

Take Dolly the lamb for example. By the process of SCNT, an egg from an egg cell donor with a new nucleus from a somatic cell donor was then stimulating to divide, a lot! This created a little embryo which was implanted into a third surrogate mother sheep who brought this new little lamb to term. And thus Dolly was born! An exact genetic replica of the sheep who donated the somatic cell.

OB Science Time: Abel Johansson

In all the craziness that was episode 3x04, a vital piece of information came out of it, so it’s time for OB Science Time and a discussion about Abel Johansson!!

We learned that Henrik worked as a lab assistant for Ethan Duncan on Project Leda. Not very surprising considering all that Henrik seemed to know. But learning that he took the original Castor biological material and turned it into his son, well that was shocking! But how exactly did that happen?

It appears that Henrik simply cloned the original on his own, using SCNT, or Somatic Cell Nuclear Transfer, which you can find more on here. Henrik basically took the DNA of the Castor original from the biological material he had, and inserted it into an egg cell, which appears to have been donated by Bonnie. Once that cell was actively and successfully dividing, he implanted the embryo into Bonnie, and she carried it to term. Wowza!

What does this mean about this child’s DNA? Well it will be an almost complete clone of the Castor original, without any genetic modifications. The only difference this child will have from the original is in the mitochondrial genome, which was supplied by Bonnie’s egg. You can find more on that here.  

So any synthetic sequences added into the clone DNA will not be in Abel’s DNA, meaning a functional version of whatever manipulated sequence is causing the glitch can potentially be found. This means the Castor clones are one step further toward finding a cure via gene therapy (which I discuss in regards to the Leda clones here).

Pretty exciting stuff here!!! I can’t wait to learn more :D As always my ask is open for all questions and discussions!!! Check out OB Science Time anytime right here :D

anonymous asked:

Dolly was a female domestic sheep, and the first mammal to be cloned from an adult somatic cell, using the process of nuclear transfer. She was cloned by Ian Wilmut, Keith Campbell and colleagues at the Roslin Institute, part of the University of Edinburgh, and the biotechnology company PPL Therapeutics near Edinburgh in Scotland, the United Kingdom. She was born on 5 July 1996 and died from a progressive lung disease 5 months before her seventh birthday.

Interesting. Thank you.Dolly was a female domestic sheep, and the first mammal to be cloned from an adult somatic cell, using the process of nuclear transfer. She was cloned by Ian Wilmut, Keith Campbell and colleagues at the Roslin Institute, part of the University of Edinburgh, and the biotechnology company PPL Therapeutics near Edinburgh in Scotland, the United Kingdom. She was born on 5 July 1996 and died from a progressive lung disease 5 months before her seventh birthday.

Did you know this?

Thanks. Tell me if you do

OB Science Time: Cloning

I thought I would take a moment to discuss how our lovely clones came to be in existence, or the actual process of cloning and some thoughts I have on the matter.

The type of cloning most likely utilized for the creation of our Leda clones is SCNT cloning, or Somatic-Cell Nuclear Transfer cloning. A somatic cell is any cell in the body that is not a reproductive cell. The somatic cell is taken from the organism that is to be cloned, the nucleus of this cell is extracted and placed into a donor egg cell, the nucleus is taken up by the egg cell, and then an embryo develops from this cell.

The main problem scientists run into with SCNT cloning is high fetal death rates. There is a lot about the process that is still not clearly understood, so has not been perfected. Part of the problem could be properly deactivating the donor egg cell, and then reprogramming it with the introduction of the new nucleus. This can cause problems with cell division and the overall cell cycle, causing premature death of the cells. Because Orphan Black is science fiction, it can safely be assumed that many of these problems were overcome by Ethan and his scientists during the development of the Leda clones, although these findings may not have been shared by Dyad and may be part of the problem behind the Charlotte generations (I discuss that in this post here).

Another key point in SCNT is that the organism derived from the process is not a perfect genetic match to the original. This is because only the nuclear genome is transferred from the somatic cell into the donor egg cell; the mitochondrial genome is left behind, and the donor egg cell provides the embryo with the mitochondrial genome. Therefore, the clone is really a hybrid between the original organism and the organism that donated the cell.

This second point is very interesting in the context of Orphan Black, because this could mean there is no 100% true original for the Leda clones. Aside from the fact that the clones have synthetic sequences added to their genome, they also have their mitochondrial DNA that comes from an unknown source. I would bet that all the clones have the same egg donor source, because otherwise there would be genetic variation amongst the clones and that would make the experiment moot (hahaha [high fives self]). Therefore, this could explain a difference in appearance between the Leda clones and the original, if the original turns out to be a character we already know who isn’t played by Tatiana, like Mrs. S or Marion.

Now of course, Ethan and his team could have used the original’s own egg cells as the donor for the cloning process. This is not normally done in reality, but again, science fiction gives us some leeway here. If this were the case, then the clones would be nearly true genetic identicals with the original, save for the synthetic sequences. Of course this could not have been done in the case of the Castor clones, since the original for them would have been male, and therefore not had any eggs to donate.

So those are just some thoughts I had on how the clones came to be, and the ever fascinating science behind Orphan Black!!!