New Scientist - 02.18.2020

(C. Jardin) #1
8 February 2020 | New Scientist | 19

Ancient humans

Diet Astronomy

Microbiome change
counters bee virus

Honeybee gut bacteria
have been genetically
modified to protect the
insects against a lethal
infection that can cause
colonies to collapse.
Researchers at the
University of Texas,
Austin, engineered a bee
gut bacterium to generate
RNA that disables the
deformed wing virus
(Science, doi.org/dkvq).

Cyborg jellyfish
swim a lot faster

Electronics embedded in
live jellyfish allow them
to be remote-controlled
by stimulating muscle
contractions so they swim
at three times their normal
pace. The hope is to use
the animals to monitor
oceans by adding sensors
to check oxygen content
and temperature (Science
Advances, doi.org/dkvt).

Fatal accidents rise
after clock change

The risk of fatal car crashes
goes up about 6 per cent
in the week after summer
time starts before returning
to normal. Researchers say
about 29 deadly accidents
in the US in the week after
the transition could be
avoided each year if clocks
weren’t changed (Current
Biology, doi.org/dkt5).

Lots of us are a bit
more Neanderthal

PEOPLE of European and African
ancestry have more Neanderthal
DNA in their genomes than
previously thought. This is the
finding of a study that identifies,
for the first time, the Neanderthal
genes present in modern day
people of African ancestry.
Neanderthals lived in Europe
and central Asia until their demise
some 40,000 years ago. Thanks to
genetic studies, we know that after
modern humans left Africa, they

A VEGETARIAN diet has been linked
with a lower risk of having a urinary
tract infection, at least for women.
The infections are usually caused
by bacteria from faeces entering the
urinary tract. Chicken and pork are a
major reservoir of E. coli, a bacteria
that commonly causes UTIs. So
Chin-Lon Lin at Tzu Chi University in
Taiwan and his colleagues looked at
whether vegetarians would have a
lower risk of UTIs than meat-eaters.
They looked at 9724 people in
Taiwan over 10 years and found
that vegetarians were 16 per cent
less likely to have a UTI than their
meat-eating counterparts. But
when the researchers analysed the

diets of men and women separately,
they found the protective effect was
present in women but not men
(Scientific Reports, doi.org/dkvm).
Lin says vegetarians may have a
lower risk of UTIs because they have
a lower risk of exposure to E. coli.
It is also possible that the high fibre
content in their diet helps them to
avoid constipation and reduces the
risk of E. coli growing in their gut.
However, there are caveats. For
example, the participants were all
Buddhists based in Taiwan. And
while the study tried to adjust for
some factors, it didn’t account for
pregnancy, which is a major risk
factor for UTIs. Adam Vaughan

interbred with Neanderthals,
leaving traces in each other’s DNA.
Previous research showed that
about 1.5 per cent of the DNA of
people of European ancestry came
from these events, while people of
east Asian ancestry had a bit more
than this. Because genomes of
people of African ancestry showed
little or no evidence of this genetic
exchange, Neanderthal genes
were identified in people of
European ancestry by comparing
their genomes with people of
African ancestry, assuming they
were a Neanderthal-free baseline.
To find out if this assumption

Two stars have a
strange jiggly orbit

A PAIR of distant stars are locked
in a weird, wobbly dance, probably
the result of an effect predicted
by the theory of general relativity.
One of the stars, PSR J1141-6545,
is a pulsar, a dense neutron star
that emits beams of light. It orbits
a white dwarf, which formed when
a lower-mass star ran out of fuel
and lost its outer layers.
Using years of observations,
Vivek Venkatraman Krishnan at
the Max Planck Institute for Radio
Astronomy in Germany and his
team calculated the stars’ orbits
around one another with extreme
precision and found it was wobbly.
This oddity is due to an effect
called frame dragging, which is
predicted in the theory of general
relativity and occurs when a fast-
spinning object drags space-time
around it. The researchers worked
out that the white dwarf is
spinning faster than the pulsar,
which is twirling fairly slowly at
about 2.5 rotations per second.
That indicates the system seems
to have formed in an unexpected
order. Usually, the pulsar forms
first, and then as the white dwarf
is losing its outer layers, the pulsar
sucks up that material and starts
to spin faster. In this case the
white dwarf formed first (Science,
doi.org/dkvx). LC

was correct, Joshua Akey at
Princeton University and his team
devised a new method of detecting
archaic ancestry in DNA. Looking
at genomes of people of African
ancestry in Africa and elsewhere
in the world today, this revealed
an unexpectedly high Neanderthal
signature of 0.3 per cent in people
of African ancestry, compared
with less than 0.02 per cent in
earlier studies (Cell, doi.org/dkvs).
By extension, that result means
the Neanderthal component
of the genomes of modern-day
people of European ancestry was
underestimated. Alison George

Vegetarians may have a


lower risk of getting UTIs


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