[Sally Le Page (OP)]

Donald recently wrote to us asking this question:

"Since the mitochondria was enclosed by the eukaryotic cell billions of years ago, how much variation is there between mitochondria of different species, families, classes and phylum? And since mitochondria are now replaced in human embryos, what prevents replacing human mitochondria with nonhuman mitochondria?"

What do you think?

[evan_au]

Mitochondria are in a symbiotic relationship with their host species.
- They respond to cellular growth signals
- They respond to energy demands
- They produce many RNA sequences that are needed for building proteins (like transfer RNA)
- They communicate extensively with the host cell and its DNA through chemical and RNA signals
- So they may not work well in another species

Structurally, in some species Mitochondrial DNA (mtDNA) consists of one or several circular rings, while other species have linear mtDNA.
-There are also enormous variation in the size of mtDNA (measured in the number of DNA bases)

since mitochondria are now replaced in human embryos

I think you are talking about nuclear transfer to avoid mitochondrial diseases
-This is not transplanting the mitochondria - this is a complete cell + mitochondria + cytoplasm +cell wall transplant, which offers even more opportunities for incompatibility
- Ethics committees are just now coming to terms with human to human nuclear transfer to avoid mitochondrial diseases.
- I expect it they will be even more reluctant to allow human nuclear Xenotransplant

See: https://en.wikipedia.org/wiki/Mitochondrion
https://en.wikipedia.org/wiki/Mitochondrial_DNA

[Zer0]

Thanks for the insights Evan!

You Really contribute to the Forum in a very positive manner.

Great Work!