New Scientist 2018 sep

8 September 2018 | NewScientist | 7

MAKING dozens of changes to

DNA in human egg and sperm

cells or very early embryos could

dramatically extend the lifespan

of offspring – according to

the first attempt to quantify

potential benefits of germline

genome editing.

“This... shows that we could

potentially use germline gene

editing to make us all resistant

to diseases of old age,” says

biomedical ethicist Christopher

Gyngell at the University of

Melbourne, Australia, who was

not involved in the study.

It is already possible to prevent

genetic diseases caused by single

mutations, such as cystic fibrosis –

by screening IVF embryos before

implantation, for instance.

But we all carry thousands of

gene variants that don’t inevitably

lead to diseases, yet affect our risk

of developing them. Changing

one wouldn’t have a big impact,

but changing many could

potentially add years to lives that

would otherwise be cut short. This

may be possible in the next few

decades, says Roman Teo Oliynyk,

a computational biologist at the

University of Auckland, New

Zealand. For instance, CRISPR

genome editing has been used to

make multiple changes to animal

egg cell genomes.

Oliynyk looked at gene variants

known as SNPs that affect the risk

of developing diseases of old age,

including heart disease, type 2

diabetes, stroke, Alzheimer’s,

osteoarthritis and some cancers.

From these it is possible to

estimate whether a person has a

greater or lower risk of developing

these diseases.

Oliynyk modelled what would

happen if those with a higher-

than-average risk had undergone

genome editing before birth to

reduce their risk to the average.

This would mean altering dozens

of SNPs – even hundreds in those

with the highest risk. The findings

suggest the results would be

dramatic, with people on average

living many years longer before

developing these diseases.

The benefits would be greatest

for cancers. Those treated would

live two decades longer, on

average, before developing breast,

prostate or colorectal cancers, and

their lifetime risk would be more

than halved, even if they live 10

years longer (bioRxiv, doi.org/ctjp).

However, as Oliynyk

acknowledges, his conclusions

depend on several assumptions.

One is that we have correctly

identified SNPs that affect disease

risk. In reality there is still huge

uncertainty. “I don’t think we are

there yet. I’m not sure we ever will

be,” says geneticist Helen O’Neill

of University College London.

She points out that the effect

of gene variants can depend on

the environment and other gene

variants and may prove impossible

to accurately predict.

Another assumption is that

altering SNPs has no side effects,

says Ali Torkamani of the Scripps

Research Institute in La Jolla,

California. “There is often a trade-

off to be had – you’ve reduced your

risk for coronary artery disease but

you may have increased your risk

for some other disorder,” he says.

There is also a major practical

problem, says O’Neill. You can’t

know what SNPs an embryo will

inherit until it forms, so you can’t

work out risk in advance. But if

you wait until this stage, it may

be too late to edit the genome.

Oliynyk thinks the answer could

be the use of synthetic genomes –

rebuilding genomes from scratch

and correcting disease-causing

variants. This is not yet possible

with large genomes like ours, but

Oliynyk is confident it will be.

“It is a purely technological

issue, and these are always

solved,” he says. Michael Le Page ■

For more on gene editing, see page 14

THE US Army is taking wireless
recharging to new heights, by
using lasers to power small drones
in mid-air.
Small multicopters – flying vehicles
with several rotating blades – have
proven valuable to the military for
intelligence gathering. But they
are power-hungry, meaning that
their flying time is limited to half
an hour or less.
Now the US Army’s
Communications-Electronics Research,
Development and Engineering Center
based in Maryland is developing
a power beaming system with a
combination of lasers and efficient
photovoltaic cells.
The aim is to provide enough
power from 500 metres away to
keep a drone patrolling indefinitely
above a base, or flying over a convoy
for its entire route. The system works
by firing laser light at photovoltaic
cells on the drone, which then
converts the light into electricity.
“The major challenge we see is
thermal management,” says project
engineer William Rowley. Any energy
that is not converted to electricity
becomes heat, so there is a risk
of melting or burning the drone.
This problem is being overcome by
developing accurate beam control
and ensuring the excess heat can
dissipate.
The plan looks technically feasible,
according to David Anderson at the
University of Glasgow, UK. However,
proving its safety is another matter,
given the potential risks from the
high-energy beam, such as eye or
skin damage.
“The challenge is how you can
convince the regulatory authorities
that it is safe,” says Anderson.
“Specifically, you have to persuade
them that the laser will not miss
the drone energy collector panel
when charging.”
The team aims to demonstrate
a first working system in 2019.
David Hambling ■

DNA editing before birth

may bring healthier lives

JADE ALBERT STUDIO/GETTY

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“ Those treated would live

two decades longer on

average before developing

a range of cancers”

Drone can fly

indefinitely by

laser power

Genome engineering could reduce

disease risk in generations to come