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Asked by *Kenzie* to David, Gemma, Juhi, Matt, Stéphane, Yinka on 8 Mar 2018.
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Juhi Gupta answered on 8 Mar 2018:
Interesting question! For cloning, the nucleus of a specific cell type (e.g. skin cell) is inserted into an empty egg cell. This will then develop into a ball of cells with the same genetic information as the original skin cell.
There are ways whereby genes can be incorporated into the DNA of organisms. For example, a protein that releases a blue colour can be inserted into the plasmid of a bacterium cell, which will cause it to look blue (instead of white) when it grows.
Reprogramming of cells was a method discovered by scientists working on stem cells. Induced pluripotent stem cells (iPSC), is a way of using an adult cell and reprogramming it back into a stem cell with the potential to specialise into another cell type. Scientists managed to make this work by using genes that are involved with creating stem cells into a specific cell type e.g. liver cell. In theory, this could be used to produce any cell type.
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Stéphane Berneau answered on 9 Mar 2018:
There is a very interesting case study: the baby with three parents.
The egg from the mother was fertilised from the sperm of the father. However, the mitochondria were defective. Therefore, they replaced them with mitochondria from another woman’s egg (ethically approved). And you get a 3 parents baby.
Did you know that only mitochondria (contains DNA) from the mother are transmitted to the offspring?
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Gemma Chandratillake answered on 9 Mar 2018:
When you clone by somatic cell nuclear transfer, as was done with Dolly The Sheep, you take the nucleus (which contains the DNA) from an adult cell, and put it into an egg from which you have removed the nucleus. Something in the egg reprogrammes the DNA to know that it is a now a zygote (a fertilised egg/an egg with two sets of chromosomes). I don’t think we know precisely how that works yet, so we can’t reprogramme a stem cell back to a zygote without using an egg (though we can programme a stem cell to make other tissues). The experiments (somatic cell nuclear transfers) are difficult to do and you’d waste a lot of eggs. Cloning is banned for the purposes of making a whole new person in many countries, and we haven’t done it in humans – there was a claim a couple of years ago that it had been done by a group in Asia, but that turned out to be fake.
Three parent embryos involve transferring nuclear DNA from an egg with unhealthy mitochondria to an egg with healthy mitochondria from which the nuclear DNA has been removed, but this is not the same as cloning!
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