In the famous Dolly the sheep an egg cell was required. Why was specifically an egg cell required compared to say sperm cells or any other cell types?

Given that egg cells are not trivially harvested and culturable, have clones from alternatives been attempted?

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    $\begingroup$ This question doesn't show a lot of effort or nuance, but I am a bit puzzled why someone voted to close it for not being clear without providing some sort of comment. $\endgroup$
    – Bryan Krause
    Commented Mar 30, 2017 at 21:49
  • $\begingroup$ I think this question deserves a chance and could yield some interesting answers. I've edited it to clear up any uncertainty. $\endgroup$
    – James
    Commented Mar 31, 2017 at 6:49

1 Answer 1


egg cells are not required for cloning, plants for instance can be cloned just fine without them. Oocytes are commonly used in animals becasue they already contain some of the chemical markers and enzymes to begin development in the mother's body and keep her immune system from attacking it. In more derived animals development is not solely controlled by the the embryo but also by the mother, so using an egg cell helps trigger those processes of the mother. If you used a standard stem cell likely the mother immune system would just destroy it as a foreign entity.

  • $\begingroup$ "some of the chemical markers and enzymes to begin development" is almost an understatement.While it is almost possible to make specific cell types out of stem cells, the processes needed for embryo development are even more complex than that and as of today noone would be able to make a stem cell into an viable egg cell or embryo $\endgroup$
    – Nicolai
    Commented Jul 29, 2017 at 10:47
  • $\begingroup$ Actually they have in mice, the-scientist.com/?articles.view/articleNo/47256/title/… $\endgroup$
    – John
    Commented Jul 29, 2017 at 14:40
  • $\begingroup$ oh wow, I didn't know that (was already possible). Thanks for the link. $\endgroup$
    – Nicolai
    Commented Jul 29, 2017 at 16:19

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