Blog Post #3 – Should we clone humans?

Hello everyone!

My inquiry Question: Should we clone humans?

In my first round of research, I will be looking into what cloning is, the history of cloning, and a few animals that have been cloned!

Firstly, there are three types of cloning!

  1. Reproductive cloning: Creates copies of an entire animal [1]
  2. Gene cloning: Creates copies of segments of DNA or genes [1]
  3. Therapeutic cloning: Creates embryonic stem cells which scientists can use for experiments to try and produce tissues to replace diseased or damaged tissues [1]

For my rounds of research, I will be focusing on reproductive cloning!

What is cloning?

Cloning is a technique used by scientists to create exact genetic copies of living things [2]. In humans, twins are natural clones [3]. Clones contain an identical set of genetic material located in the nucleus which is in the compartment that contains the chromosomes [3]. Cells from two clones have the same DNA and the same genes in the nuclei [3].

There are two methods of creating living mammal clones and both require implantation of an embryo in a uterus: “Cloning using somatic cell nuclear transfer” and “Cloning by embryo splitting” [3].

 “Cloning using somatic cell nuclear transfer”: [3]

  • FIrstly, you start with the removal of the chromosomes from an egg to create an enucleated egg
  • Chromosomes are then replaced with the nucleus taken from a somatic cell of the individual or the embryo to be cloned
  • Egg becomes stimulated which means it may start to divide
  • If the egg starts to divide, a series of cell divisions leads to form what is called a blastocyst or a preimplantation embryo
  • The blastocyst is implanted into the uterus which can result in further development, sometimes resulting in the birth of an animal.
  • The animal is a clone to the individual who donated their nucleus. Its nuclear DNA is inherited by only one genetic parent

“Cloning by embryo splitting”: [3]

  • This method of cloning begins with in vitro (in the glass like a test tube, for instance) fertilization
  • Outside of the woman’s body, a sperm and an egg will generate a zygote 
  • It will then divide into two and then into four identical cells at this stage, the cells can start to separate and are allowed to develop identical blastocysts
  •  These identical blastocysts will then be able to be implanted in a uterus
  • However, there is a limited development potential of the cells meaning that the procedure cannot be repeated
  • The embryo splitting can only create no more than four humans and only two mice
  •  The DNA in the embryo splitting is contributed from two individuals who give their germ cells – the mother and father who contributed their egg and sperm.

History of cloning: 

In the 1900’s, Hans Spemann observed into blastomeres that dislocated from the early salamander embryos that were developed into normal individuals [5]. Which suggested there was no gene loss at the early stage of development [5].  

In 1901, the cloning method of transferring the nucleus of a salamander embryonic cell to an enucleated cell was a success [5]. John Gurdon did an experiment by using a technique to produce viable frogs by using a nuclear transfer from intestinal epithelium cells [5]. His work demonstrated that cell differentiation takes place without gene loss [5]. As well as if the differentiated cells are exposed to the oocyte’s cytoplasm then cellular commitment may be reversible [5]. During the 1940s to 1950s, scientists were able to clone embryos in mammals [5]. In 1962, a mature frog was produced by transferring the nucleus of intestinal cells of tadpoles into the eggs while their nucleus was removed [5]. Keith Campbell had done experiments and became successful in producing two sheep clones from an embryonic cell line [5]. 

In 1996, scientists cloned the first animal, Dolly the sheep [2]. She was cloned by using mammary gland cells that were taken from an adult sheep [2]. Dolly, the sheep’s birth was quite moving because it had proved that the nucleus of the adult cell had all the DNA necessary to give another animal life [6]. Dolly died in 2003 at age six from lung infection which is common in animals who do not go outdoors [6].

Since Dolly’s birth, scientists have been able to clone cows, cats, rabbits, horses, cats, and dogs! [4]. However, scientists have not been successful in cloning a whole human [1]. 

In my second round of research, I will look into the advantages of cloning! 

Thank you for reading my first round of research!







[6] (image)

4 Replies to “Blog Post #3 – Should we clone humans?”

  1. Hey Karina!

    I remember Dolly from early-day science classes, and I like that you are speaking about animals’ experiences with cloning to set a good foundation. I have three questions for you:
    1. In Reproductive cloning, do the cloned animals have the same immune system progress as the cloned animal, or is it a clean slate, where any immunity issues would not carry over?

    2. Would you like to clone yourself, if you could? 😉 Why/why not?

    Here are two resources I found:
    National Geographic’s web page about cloning:
    (They get into examples of dogs, to monkeys as well!)
    StatNews’s article on how it’s “technically possible to clone humans” was a pretty sweet read!:

    Looking forward to seeing your striving progress in your super cool inquiry project!

    Warm Regards,


  2. Hey Karina!
    Wow! I had no idea there were specific types of cloning. I liked how you explained the science briefly and concisely. It really helped in understanding the process of cloning better.
    Do you plan to look into some of the ethical questions surrounding cloning perhaps? I know that it is heavily debated among scientists around the world. What do you think?
    Here’s a link that I found addressing the question a little further:
    Great start to your research. Can’t wait to see what comes next!

  3. Hi Karina,
    That was really cool about Dolly getting cloned using mammary gland cells from an adult sheep. I’m very curious on the process of her growing up. Good work and I’m looking forward to the nest post.

    • Lucas,
      I was actually not sure if I should include more about Dolly proccess of growing, however, I may include it into my third round of research! Thank you!

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