10 | New Scientist | 8 June 2019
News
A NATURALLY occurring gene
variant known to make people
resistant to HIV infection may also
make them more likely to die a
little early, according to a study
of 400,000 people in the UK.
Called CCR5, the gene involved
is the one targeted by He Jiankui,
the Chinese scientist who last year
created the first gene-edited
babies to try to make HIV-resistant
children. The new study suggests
we don’t know enough about
the full effects of most genetic
variants to be sure that giving
them to people will be beneficial.
“This is a good example of the
great danger of manipulating
genes in humans when our
understanding of the function
of most genes is so rudimentary,”
says Alcino Silva at the University
of California, Los Angeles.
The CCR5 gene codes for a
protein that protrudes from
some of the cells in our immune
system and in our brain. HIV
infects immune cells by first
binding to this protein, and some
people are naturally resistant to
HIV because they have a mutation
in both their copies of the CCRgene that disables this protein.
As well as making people
resistant to HIV, this mutation has
been linked to improved stroke
recovery. But the mutation may
also have negative effects, such as
making people more vulnerable
to some other viruses, including
West Nile and, possibly, flu.
Rasmus Nielsen at the
University of California, Berkeley,
and his colleagues analysed data
on 400,000 people in the UK
Biobank. They found those withtwo copies of the CCR5 variant
were 20 per cent more likely to die
before the age of 76 than people
with no more than one copy
(Nature Medicine, doi.org/c6pj)
The study suggests such people
would live around two years less
on average, says Luke Jostins-Dean
of the University of Oxford. He
says the research shows that weshouldn’t engineer this mutation
into children.
In his experiment, He
attempted to use CRISPR gene
editing to induce the same
mutation in IVF embryos from
couples where the father was HIV
positive. “The girls are safe and
healthy as any other babies,” he
said in a video announcing the
birth of two children. His actions
were condemned as unethical for
many reasons, including the fact
that the full consequences of this
mutation aren’t yet understood.
We don’t know if the gene-
edited girls are likely to die earlier.
Although He attempted to mimic
the naturally occurring CCR
mutation, he reportedly induced
different mutations in the gene.
Additionally, these mutations
aren’t present in every cell,
says Robin Lovell-Badge of the
Francis Crick Institute in the UK.
What’s more, the effect of
mutations in CCR5 could be
different in different populations
exposed to different diseases.
“The UK Biobank is certainly not
representative of the population
of China,” says Jostins-Dean. ❚OUR hominin ancestors were
routinely making stone tools
more than 2.6 million years ago –
10,000 years sooner than thought.
The find hints at multiple origins
of tool use in early humans.
David Braun of George
Washington University in
Washington DC and his team
have been analysing a collection
of ancient tools at Ledi-Geraru
in Ethiopia.They discovered them just
5 kilometres from where the oldest
known fossil of our Homo genus,
a jawbone from 2.8 million years
ago, was found in 2013.
“We think it makes the most
sense that early Homo made those
stone tools,” says Braun. But he says
we can’t rule out the possibility that
a more ape-like hominin, such as
Australopithecus, was responsible.
The style of the artefacts
classifies them as Oldowan stone
tools, which were widely used by
hominins over the next million
years. Previously, the oldest
known Oldowan examples were2.6-million-year-old tools from
Gona, Ethiopia. Those from
Ledi-Geraru are up to 2.61 million
years old.
The team compared the
Ledi-Geraru tools with other
collections, including those from
Gona, and found they were crude.
The tools had “significantly lower
numbers of actual pieces chipped
off a cobble than we see in any
other assemblage later on”, saysBraun. The toolmakers may
have been less skilled, or they
may not have needed their tools
to be particularly sharp (PNAS,
doi.org/c6rw).
But while the Ledi-Geraru tools
are broadly similar to later Oldowan
tools, they are drastically different
to the oldest known stone tools,
which were found at Lomekwi in
Kenya and are 3.3 million years old.
“Those have nothing whatsoever
to do with what we see later on,”
says Braun. “It’s possible there are
multiple independent inventions
of stone as a tool.” ❚
Michael MarshallEarly humans may
have developed tool
use several timesArchaeology“ They are drastically
different to the oldest
known stone tools, which
are 3.3 million years old”HIV resistance shortens life
A genetic variant fends off the virus but is linked to reduced lifespan
Human geneticsMichael Le PageVC
G/VCG
VIAGETTY^ IMAG
ESHe Jiankui was the
first person to create
gene-edited babies