
First 'three person baby' born using new method - tpatke
http://www.bbc.co.uk/news/health-37485263
======
rcthompson
Sounds like mother & father's nuclear DNA, injected into the nucleus of a 3rd
party's donor's egg cell, which contains its own mitochondrial DNA. Since
mtDNA is normally inherited 100% from the mother (since the mother's egg cell
supplies the mitochondria to the embryo), if the mother has a mitochondrial
genetic disease, 100% of her children would normally inherit it.

~~~
nkrumm
Yes-- the inheritance of mtDNA is maternal, but interestingly not 100% of her
children will inherit the disease. This is because the mother will have a mix
of mutated (diseased) mtDNA and wild-type (healthy) mtDNA in each of her
cells, including her eggs. Some of the eggs will have close to all mtDNA
mutated, but many will have a relatively low mutational burden. (This
variation amongst the mother's cells and eggs is called heteroplasmy). Most
mitochondrial genetic diseases have a heteroplasmy threshold (varying by
gene/pathway, between 30-90% for many); when the overall burden in a
fertilized egg is above this threshold, the disease is manifested in the
offspring. Thus, another way to circumvent the transmission of mtDNA diseases
is by using regular in vitro fertilization, and checking one of the cells at
the 16 or 32 cell stage for their heteroplasmic content.

Here are some references:

Lightowlers, R. N., Taylor, R. W., & Turnbull, D. M. (2015). Mutations causing
mitochondrial disease: What is new and what challenges remain? Science,
349(6255), 1494–1499.
[http://doi.org/10.1126/science.aac7516](http://doi.org/10.1126/science.aac7516)

Taylor, R. W., & Turnbull, D. M. (2005). Mitochondrial DNA mutations in human
disease. Nature Reviews Genetics, 6(5), 389–402.
[http://doi.org/10.1038/nrg1606](http://doi.org/10.1038/nrg1606)

Smeets, H. J. M., Sallevelt, S. C. E. H., Dreesen, J. C. F. M., Die Smulders,
C. E. M., & Coo, I. F. M. (2015). Preventing the transmission of mitochondrial
DNA disorders using prenatal or preimplantation genetic diagnosis. Annals of
the New York Academy of Sciences, 1350(1), 29–36.
[http://doi.org/10.1111/nyas.12866](http://doi.org/10.1111/nyas.12866)

~~~
ralfd
> checking one of the cells at the 16 or 32 cell stage

I wonder: How is an embryo dealing with missing a cell at this early? Does
this error compound after a few doublings (embryo is smaller)?

~~~
pmalynin
AFAIK it shouldn't be issue. Some twins (identical twins) are created when a
two cell organism detaches into two separate entities.

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heydenberk
Notably, this prevents transmission of a disease that is "fatal to any baby
conceived", which makes this as uncontroversial a case of a "designer baby" as
I can imagine. After this, the ethics get much more complicated.

~~~
afarrell
It occurs to me: What _are_ the ethical problems with designer babies?

~~~
dflock
In a world with "designer babies", the rich don't just get richer, they get
smarter, stronger, more attractive and start to live longer.

The poor can't afford this, so fall further and further behind, perhaps
eventually humanity splits into subspecies.

This is very well trod ground. See The time machine by H G Wells with the
Morlocs and Eloi, A Brave New World by Aldous Huxley with the Alphas and
Betas, etc, etc...

~~~
runeks
So the more powerful a technology is in changing our capabilities as human
beings, the more unethical it inherently is, because poor people will have
less access to it (assuming it costs money)?

I'm not arguing on the validity of this world view, but it does seems very
negative to me, since it can be applied to any powerful technology (that isn't
free of charge).

I mean, computers and internet access also costs money, so does this mean that
the introduction of these technologies presents an ethical problem, because
the poorer part of the population may not be able to afford it, thus
increasing inequality?

~~~
jlgaddis
Just today there was an article in the newspaper of a nearby town stating that
the school system there would be moving to "paperless" report cards; that is,
report cards would be entirely online. (It did mention that parents could
request a printed copy of their child's report card at any time.)

My first thought was "not everyone has Internet access" \-- especially in this
relatively small city -- and the possible ramifications of that.

Will those parents have to request a paper copy every time a report card is
issued (four times per school year)? Will they eventually stop doing so? Will
they stop paying attention to their child's academic progress and will the
child's academic performance then suffer? Will the child slowly begin to
perform worse and worse (academically) over time?

Will this "digital divide" simply continue to worsen?

~~~
milcron
Internet access should be a public utility.

~~~
Esau
Some people can't afford public utilities either.

~~~
int_19h
Then perhaps that is a problem that we should tackle, instead of going all
Luddite about fairly basic tech because someone cannot afford it?

I even wouldn't be surprised if it resulted in a net economic benefit, because
the reduced overhead of new tech is less than amount of money you need to
spend to make sure that everyone has access to it.

~~~
bitJericho
Libraries already tackle this. As well as other organizations. For example,
when I was a kid my main internet pc was at the state extension office.

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elevensies
If I'm understanding correctly, this could be used for cloning if you could
select two nuclei with non-overlapping chromosomes from a single person's
sperm/eggs ... much easier to clone a man due the limits of egg extraction.

back of the envelope:

\- each gamete has 1 of 2 choices for 23 chromosomes.

\- you need to find any two non-overlapping

\- probability of non-overlap is 0.5^23 for any pair

\- number of pairs equals (n choose 2) where n is number of gametes = n!/ (2 *
(n - 2)!) = 0.5 * n * (n-1) = 0.5 * (n^2 - n)

\- to get a 50/50 chance of finding the right gametes: 0.5 = 0.5^23 * 0.5 *
(n^2 - n), which is equivalent to: 0 = 0.5^23 * (n^2 -n) - 1

\- solved via wolfram alpha, you would need to screen 2897 nuclei non-
destructively to get a 50% chance of being able to generate a clone.

I'm not aware if this is possible or not. But obviously if you can just
replace chromosomes in-nucleus that is easier than screening, but if you can
do that you don't really need this whole process since you can just replace
the nucleus after IVF. If you could harvest a sex cell and do meiosis in a
test tube, that would also get you your nuclei right away as well -- from 10
seconds of googling, I don't think we have this yet.

I think when they screen zygotes they do it after some replication has
happened, so the math really works against you if you need to combine
sperm+egg pre-screen because you don't get the birthday paradox effect if you
have to commit to your pairings beforehand, you'd need to huge egg supply as
well.

------
vermontdevil
Interesting they had to go to Mexico to perform this procedure.

~~~
dethstar
From another article[0]

>Neither method has been approved in the US, so Zhang went to Mexico instead,
where he says “there are no rules”.

[0][https://www.newscientist.com/article/2107219-exclusive-
world...](https://www.newscientist.com/article/2107219-exclusive-worlds-first-
baby-born-with-new-3-parent-technique/)

------
mcphilip
Additional background info from last year:

[http://www.bbc.com/news/health-31594856](http://www.bbc.com/news/health-31594856)

------
jack9
> But the science does raise ethical questions, including how any child from
> the technique might feel about having DNA from three people.

That's not an ethical problem. Also, not a problem since, it's not any kind of
problem to consider how kids might like PB&J sandwiches either.

~~~
brian-armstrong
You can't just brush it off and say it isn't a problem. Having 3 biological
parents is incredibly rare and could have weird social effects for the child.
It is an ethical concern if it affects how they relate to other people.

~~~
mnw21cam
How is this different to someone who has two parents, but has had a kidney
transplant from a third person?

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halhod
the original story, with more detail, is here
[https://www.newscientist.com/article/2107219-exclusive-
world...](https://www.newscientist.com/article/2107219-exclusive-worlds-first-
baby-born-with-new-3-parent-technique/)

------
Raphmedia
And polygamy is stil illegal. I can father a child with my two girlfriends but
cannot marry them both. Bah!

~~~
spacehome
You dodged a bullet there, trust me.

------
fasteo
Note that this will not stop some kids from getting these type of diseases,
collectively known as mitochondrial myopathies.

Some of them arise sporadically [1]

    
    
      In chronic progressive external ophthalmoplegia (CPEO) — a myopathy with the defining features of ophthalmoplegia and ptosis — Δ-mtDNAs are found only in muscle (implying that the deletion event occurred after fertilization in the muscle lineage of mesoderm).
    

How do I know ? I have a mitocondrial myopathy (CPEO). My mother was perfectly
healthy and all my brothers and sisters (5) are also ok.

[1]
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3959762/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3959762/)

------
contingencies
mtDNA is also very significant in historical migration studies... if anyone
has a high level explanation of the global state of knowledge in this area I
would love to see it ... trying to author a regionally focused ancient history
book and piecing together the disparate pieces of supposed genetic evidence
for various things is a task I am wholly unqualified for and would love some
assistance with.

~~~
misiti3780
This book did a great job, but it might be outdated:

[https://www.amazon.com/Power-Sex-Suicide-Mitochondria-
Meanin...](https://www.amazon.com/Power-Sex-Suicide-Mitochondria-
Meaning/dp/0199205647)

~~~
Symmetry
In another of Nick Lane's books he mentions compatibility between nuclear and
mitochondrial DNA as a possible reason for variation in fertility in different
species. If that's true I'd expect the 3-parent process to produce fewer
pregnancies per fertilized egg than the normal 2-parent method which runs at
around 50%.

~~~
misiti3780
which book was that ? Life Ascending?

~~~
Symmetry
That's what I was thinking, so if you think so too then probably.

------
patrickg_zill
So let's say in the future that the child needs a bone marrow donor. Does this
cause any new wrinkles in finding a good match?

~~~
mnw21cam
Not at all. 100% of the genomic DNA of the child comes from the two parents.
This is where all the genes that determine rejection live. The mitochondria
are actually a completely separate organism that live inside our cells and
perform a useful function - they are often fairly diverse anyway.

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c3534l
Yeah, because fuck adoption. It only counts if it has your DNA, right?

~~~
shostack
OK, I'll bite...

Having a child is a very personal decision. There are many factors, and for
some, they may not feel adoption is right for them.

It doesn't mean "fuck adoption," and it certainly doesn't give you the moral
high ground to judge those who decide that having their own child is the right
decision for them.

And I'd add that three people having one child is a better ratio than two
people having one for purposes of population control if you extrapolate out
the math.

~~~
FungalRaincloud
Not only that, but this is important research, whether we have too many people
in the adoption system or not. The success of the human species relies on
pushing our boundaries, every bit as much as it relies on taking care of one
another.

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alienallys
Inshallah! What a wonderful magic, God bless these parents

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Shivetya
so science fiction of Alien Nation in a ways. so can they simply stock pile
good genes and swap them out as necessary in the near future?

~~~
grenoire
That strays into the eugenics region. Not there yet; the moral and legal
'obstacles' will be present for a long while.

~~~
wyager
I've never heard Eugenics defined in this way. I've only heard it used to mean
selective planned breeding (as we do with livestock), but not intentional
selective improvement of the parents' DNA.

~~~
seangrogg
[https://en.wikipedia.org/wiki/History_of_eugenics](https://en.wikipedia.org/wiki/History_of_eugenics)

Totally worth peeking into, it's interesting what many countries have
considered, have attempted, and are continuing to ruminate on.

~~~
sevenless
Hitler got some of his worst ideas from the Eugenics Institute in California.
Such as 'humanely' gassing undesirables and 'genetic defectives'. Eugenics,
from Galton on, was considered progressive, enlightened, 'scientific' thought
at the time.

