10 | New Scientist | 23 November 2019
News
A HANDFUL of protesters were
leafleting people arriving for a
conference on creating gene-edited
children in London last week. The
Stop Designer Babies campaign
group claimed in a press release that
those at the meeting “are planning
how to conduct GM baby experiments
without asking the public”.
It is true that this meeting was
about coming up with guidelines for
how to conduct the first clinical trials
of human germline genome editing,
making changes that could pass
down the generations. But those
involved want to consult the public,
and many think the guidelines will
deter rather than encourage further
attempts, at least in the short term.
If people have to tick off a
checklist before trials begin, they
aren’t going to get far down the list,
says Andy Greenfield at the MRC
Harwell Institute in the UK.
This meeting was a direct result
of the announcement last November
that a woman in China had given birth
to two genetically edited baby girls.
This led to the establishment of the
International Commission on the
Clinical Use of Human Germline
Genome Editing, a group of doctors,
biologists and ethicists tasked withconsidering the potential uses
of the technology and drawing up
guidelines for how to proceed.
For now, the consensus remains
that it would be irresponsible to try it.
This is because, at the group’s second
meeting last week, two broad
messages became clear. First, we still
don’t know if any of the many variants
of CRISPR gene editing are safe
enough to use for editing embryos.
Kathy Niakan at the Francis Crick
Institute in London, who is usingCRISPR to study early development,
said her team is finding that the
technique deletes large chunks of
DNA in about 20 per cent of embryos.
This was discovered only recently.
Effectively, biologists were looking
for spelling mistakes and not noticing
that whole pages were missing.
Meanwhile, Hui Yang at the
Chinese Academy of Sciences has
been trying a more precise form of
CRISPR, called base editing, in animal
and human embryos. His team has
found unintended changes too.
Yang hopes a new method called
prime editing might work better.
The second message is that manyattendees see no pressing need to
resort to editing the genomes of
human embryos. Almost all serious
genetic diseases can be prevented
by screening the genomes of IVF
embryos before implanting them
in a uterus, said Frances Flinter
at Guy’s and St Thomas’ NHS
Foundation Trust in London. This is
known as pre-implantation genetic
diagnosis (PGD). Cases where
genome editing would be the only
way for people to have healthy
children are “incredibly rare”, she said.
Several attendees questioned
the focus on genome editing
when many families have yet to get
access to existing, safer technologies
for preventing genetic disorders.
Nick Meade at Genetic Alliance,
which supports people with genetic
conditions, said not all people in
the UK who want PGD can get it.
Germline genome editing can’t
solve any pressing medical need yet,
but that may change. It is likely that
we will one day be able to generate
eggs or sperm cells from adult cells,
said Azim Surani at the University of
Cambridge. That would allow a wider
range of uses, such as treating male
infertility caused by mutations that
PA stop sperm being produced. ❚
SC
AL
GOET
GHELUCK/SCIENCE^PH
OTO^ LIBRARYWildfiresPollution from
Australia’s bushfires
hits South AmericaSMOKE particles from Australian
bushfires have reached South
America, more than 10,
kilometres away.
Satellites show that atmospheric
pollution created by fires in New
South Wales and Queensland
has reached Chile and Argentina.
Researchers at the European
Centre for Medium-Range Weather
Forecasts (ECMWF) in Reading, UK,found a plume of carbon monoxide
and aerosols trailing across the
Pacific Ocean to South America.
More pollution will follow,
says Mark Parrington at ECMWF.
“There’s still thick smoke coming
out of New South Wales,” he says,
“so more will be being pumped out,
meaning a train of pollution going
across the south Pacific, following
the jet stream.”
While it is unusual for pollution
to travel so far, studies have shown
that Australia’s deadly 2009 “Black
Saturday” fires released materials
that travelled a similar distance.Only small amounts of Australian
pollution have been recorded
hitting South America this time,
with Parrington reporting carbon
monoxide levels of 80 to 100
parts per billion. Anything above
110 ppb is considered polluted air.
However, it is unlikely the
pollution will affect local air quality
in South America since the material
is around 5 kilometres up in theatmosphere and likely to stay there.
Still, says Parrington: “If the air
comes down and reaches the
surface, it could add an extra bit
on top of local air quality issues.”
Instead, the significance of the
pollution reaching so far is what it
tells us about the power of the fires
in Australia. “It’s reflecting the sheer
intensity of the fires, particularly in
New South Wales,” says Parrington.
Australian fire chiefs have
warned that with little rainfall
expected imminently, the fires
could continue for weeks. ❚
Adam VaughanModifying human
embryos will require
strict controlsConference report Human Germline Genome EditingWriting the rule book on gene-edited humans A year after
the birth of the first CRISPR babies, Michael Le Page discovers
how geneticists are setting rules for creating more“There’s still thick smoke
coming out of New South
Wales, so more will be
being pumped out”