once in a while there's a development in science that gets an unusual amount of
press often that's a good thing we discover a new subatomic particle or
detect gravitational waves for the first time or land something on Mars this time
is different last week a researcher in China
announced that he had used the gene editing technique known as CRISPR to
change the DNA of human embryos created via in vitro fertilization and that
these two embryos had been successfully implanted in their mom and developed
into twin baby girls that were born last month the experiment has been
universally condemned by scientists and according to practically every expert on
medical ethics should never have been done in the first place here's why
CRISPR is a revolutionary gene editing technique that's been used for a ton of
research in the last few years it allows scientists to delete genes turn off
genes or insert genes all more easily cheaply and accurately than ever before
in this latest experiment Huijin quai a scientist at the Southern University of
Science and Technology in Shenzhen China used CRISPR to disable a gene called
ccr5 in human embryos ccr5 is involved in the immune system and the HIV virus
exploits it in order to infect human cells so by disabling this gene he aimed
to make the babies resistant to HIV we don't know many of the details of
this experiment because who's Jean qui hasn't published the research and a
peer-reviewed scientific journal but according to reports the parents of the
babies went through IVF and shortly after the eggs were fertilized her used
the CRISPR technique to cause a genetic mutation that would disable the ccr5
gene the embryos were then implanted into their mother's uterus and were
carried to term the twin girls were born around the beginning of November and so
far they seem healthy there's been speculation that the parents may have
decided to participate in this experiment because the father is HIV
positive but there are other less risky ways to ensure that a baby with an HIV
positive parent doesn't contract the virus and then episode we did on CRISPR
back in 2016 we mentioned that scientists are aware of that just
because you can doesn't mean you should principle but it seems like who's Jean
qui was not CRISPR had been used to edit genes in human embryos before now but
only for research purposes and never with the
intention of implanting the embryos or allowing them to develop and the
consensus among both scientists and policy makers was that we were nowhere
near ready to implant genetically edited embryos we needed more research first
ethically there are still some open questions about the implications of
editing someone's entire genome before they're born whether it will lead to
so-called designer babies for example or if it's okay to alter the course of
human evolution in this way no matter how you feel about those questions we're
not ready for CRISPR edited babies because of some pretty basic safety
concerns CRISPR isn't perfect yet and sometimes it will change a gene in
unexpected ways causing an unintended mutation and the
last thing you want is an accidental potentially dangerous change in every
single cell in someone's body the few approved gene therapies that involved
directly editing someone's DNA inside of their body use older better studied
techniques not CRISPR there are a few CRISPR based treatments in trials right
now but they work by taking certain types of cells out of the patient
modifying them and then putting them back in and no matter what technique
they use all these treatments have something in common they don't touch the
germline germline cells are the ones that divide to produce eggs or sperm and
by making sure they stay unmodified you can't pass on the edited DNA to a child
so even if something goes wrong you avoid the risk of introducing that
problem to future generations who's Jean quiet basically took all
those precautions and threw them out the window for the experiment he used CRISPR
to edit DNA and very early embryos consisting of only a few cells at most
at that stage CRISPR can alter genes in every cell of the embryo which
eventually generate every cell in the fetuses body including their germline
cells even if everything had gone exactly as planned this research would
have been controversial because it skipped so many steps in the usual
careful process that goes into developing new treatments especially new
gene editing treatments but it didn't all go exactly as planned the babies are
healthy right now but the mutations in their ccr5 genes are slightly different
from the naturally occurring ones who was trying to reproduce you have no idea
if those new mutations will have other effects and now the girls are stuck with
them for the to their lives it also seems like in at
least one of the babies only half of the ccr5 genes were edited depending on how
the edited genes are distributed that could mean that she didn't even get the
HIV resistance after all that so yeah it turns out there are reasons we are
cautious about research like this but it's not just about the fact that hood
tried a treatment and it didn't work out exactly as expected that happens all the
time it's that he went against scientific consensus so strong that
there are laws to enforce it the Chinese government now seems to be investigating
him although the details of that are not yet clear either way this was not a good
strategy for pushing scientific progress scientists said pretty much agreed that
if they ever used CRISPR on a human embryo that would be carried to term
they would use it to correct a genetic disease for which there was no other
reasonable treatment in a youtube video he posted because of course this all
came out via a YouTube video who explained that he'd show us the gene
because it's extremely well studied thanks to years of HIV research but
there was no medical need for this the goal was just to make the babies more
resistant to HIV infection which they didn't have and again could have
prevented in a number of less expensive and much less controversial ways
scientists are all for progress that's kind of their job and gene editing has
the potential to completely transform the face of medicine but if there's
anything scientists have learned from past mistakes it's that we need to be
careful about how we wield that type of power because it can be dangerous too
and with CRISPR being such an amazing potential treatment the last thing we
want to do is sour the whole world on its use because of some mistakes made
early in the process here at scishow we believe the more you know about the
universe and how scientists come to understand it the easier it is to
recognize good research and realize when science has gone astray it's one reason
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