18 | New Scientist | 26 October 2019Animal behaviourDNA tweak lets you
get by on less sleepA GENETIC mutation that allows
people to feel fully rested with
fewer than 6 hours sleep a night
has been identified, the second
such finding in recent months.
Ying-Hui Fu at the University of
California, San Francisco, and her
colleagues have been studying
families in which some people
seem to need less sleep than
normal. Her team has found
several mutations that meanCosmic rays helped
form dunes of TitanTITAN is the only other place in the
solar system with liquid oceans on
its surface, but it also has swathes
of desert covered in sand dunes.
The material that makes up these
dunes is commonly assumed to
have fallen from the sky, but a new
study suggests it may have been
made on the ground instead.
The dunes on Titan, Saturn’s
largest moon, stretch across its
equatorial region and are up to
100 metres high. Images from
NASA’s Cassini probe have shown
that the dunes contain some dark-
coloured organic molecules, based
on long chains of carbon atoms.
We also see organic molecules
in Titan’s thick, hazy atmosphere,
leading many researchers to infer
that they form there and then fall
to the ground. But Ralf Kaiser at
the University of Hawaii at Mānoa
and his colleagues have found that
they may form on the ground tooSolar system^ GeneticsA BIRD that migrates from
northern Europe to sub-Saharan
Africa seems to synchronise its
flying with phases of the moon.
The European nightjar’s behaviour
is the first time a link has been
shown between animal migration
patterns and the lunar cycle.
Nightjars feed at night. We
already knew they change feeding
habits based on the moon’s phase,
gobbling more insects on moonlit
nights, but not if they schedule their
migration in a similar way.
To find out if they do, Gabriel
Norevik at Lund University in
Sweden attached tracking devices
to 39 European nightjars. The
measurements reveal a key role
of the full moon in the nightjar’s
itinerary, which consists of long
night-time flights with daytime
resting punctuated by muchlonger rests at stopover sites.
On moonlit nights, the birds’
foraging during migration stopovers
more than doubled. Then, as the
moon wanes, increasing numbers
of nightjars embark on migratory
flights, peaking at around 11 days
after a full moon. Sometimes, all
of the tracked birds would migrate
simultaneously at this time.
Norevik says he and his team
were astounded by how well the
activity pattern followed the cycles
of the moon. This is the first time
lunar phase has been identified as
a regulator of migration schedule
(PLoS Biology, doi.org/dcvr).
Cecilia Nilsson at Cornell
University in New York says the
findings raise questions about
the impact of artificial lights on
migrating birds relying on the
moon. Jake BuehlerNightjar’s migration waxes
and wanes with the moon
people need less sleep. In August,
Fu’s team reported on a gene
called ADRB1. It allows 12 members
of a family to sleep as little as
4.5 hours per night without feeling
tired. This gene codes for a protein
common in the brain’s dorsal pons
area, known to regulate sleep.
Now the team has found a
mutation in a gene called NPSR1 in
another family. Of the two family
members whose sleep habits they
studied, one averaged 5.5 hours a
night and the other just 4.3 hours.
NPSR1 codes for a brain protein
known to be involved in arousal
and sleep behaviour. When the
team engineered the mutation
into mice, they slept less without
any obvious effect on health or
memory (Science Translational
Medicine, doi.org/dcvx).
On average, people need 8 hours
sleep a night. As far as Fu’s team
has been able to tell, however,
people who sleep less because they
have one of these gene variants are
healthy and don’t appear to suffer
any ill effects. Michael Le Pagein a process that could also take
place on other worlds.
Cassini found the signature
of acetylene ice in the same
regions as the dunes on Titan,
so Kaiser and his team performed
an experiment to see if this ice
could be chemically converted
into complex organic molecules.
They bombarded acetylene ice
in a laboratory with high-energy
radiation similar to the cosmic
rays that propagate through the
galaxy, then heated the ice up
until it sublimated so they could
determine its final make-up.
They found that radiation
hitting the ice did cause it to react
chemically to create the organic
molecules we see in Titan’s dunes
(Science Advances, doi.org/dcvz).
These molecules are also probably
created in the atmosphere, so they
could come from there as well,
says Ralph Lorenz at Johns
Hopkins University in Maryland.
All may become clearer when
NASA’s Dragonfly craft lands near
Titan’s dunes in 2034. Leah CraneDAVID TIPLING/GETTY IMAGES
PHANIE / ALAMY STOCK PHOTONews In brief