ADVANCES
20 Scientific American, November 2018
IN THE NEWSQuick
Hits
By Ankur PaliwalINDONESIA
Jakarta is sinking fast.
Indonesia’s capital is built
on ground that is subsiding
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sea-level rise, and about
95 percent of North Jakarta
could be underwater by- The government is
now building a 32-kilometer
seawall to protect the city.
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nov2018/advances
U.S.
Scientists mapped one
of the world’s fastest-
moving underwater faults
in Alaska, which has a slip
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year. These data could
help coastal communities
in Alaska and Canada
prepare for earthquakes
and tsunamis.
THE NETHERLANDS
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to open near the port of Rotterdam by the end
of the year. The idea is to produce food closer
to urban areas, where two thirds of people will
live by 2050, and to reduce pollution caused
by transporting food over long distances.SOUTH AFRICA
South Africa has completed MeerKAT, the largest
and most powerful radio telescope in the Southern
Hemisphere. The telescope—part of the multicontinent
Square Kilometer Array—will study how hydrogen gas
®¹ÿyå ́ï¹D ̈Dāyåï¹ùy ̈åïDà¹à®Dï¹ ́ÎJAPAN
The Japanese government has lifted its ban
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The ban was imposed following reports of
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drug, but scientists have found no direct
̈ ́§UyïĀyy ́5D®ùùåyD ́mïåUyDÿ¹àÎNIGERIA
%yàDDå ̈Dù ́`ymïåàåïày ́yĀDU ̈yy ́yàĂ
association, with the goal of generating about
40 percent of the country’s total energy from
green sources by 2030. More than 50 percent
of the population currently lacks access to any
energy sources.SLEEP SCIENCE
To Sleep,
Perchance
to Gene
Researchers identify genes linked
to rapid eye movement sleep
Scientists have known about the stage of
sleep called rapid eye movement, or REM—
which is associated with dreaming as well
as improved learning and memory—since
the 1950s. Many of its mechanisms remain
mysterious, however. Now a study has iden-
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Mice that lack the genes Chrm1 and
Chrm3 sleep fewer hours than typical mice
and have almost undetectable REM levels,
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scientists have homed in on genes essen-
tial for REM sleep, says Hiroki Ueda of
Japan’s RIKEN Center for Biosystems
Dynamics Research, who conducted the
study published in August in Cell Reports.
Ueda and his colleagues focused on
the neural signaling chemical acetylcholine
and its receptors in brain cells. Previous
research had linked acetylcholine to REM
sleep regulation, but Ueda’s team wanted
î ̧³l ̧øîÿ`äÇx``x³xäD³lßx`xÇ-
tors were involved. Using a variation of the
gene-editing method CRISPR/Cas9, they
produced seven mice lacking genes that
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5xāxDäøßxl2$D³l³ ̧³2$ä§xxÇ
in the genetically altered mice and in eightcontrol mice, using electroencephalo gram
and electromyogram recordings.
Mice without both the Chrm1 and
Chrm3 genes slept less than the normal
mice and got almost no REM sleep, the
researchers found. Mice lacking only
Chrm1 had shorter and more fragmented
REM sleep; those without only Chrm3 had
shorter non-REM sleep.
Yu Hayashi of the International Insti-
tute for Integrative Sleep Medicine at
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5äø¦øUDjÿ ̧ÿDä³ ̧î
involved in the study, says the results could
mean that REM sleep is not necessary for
survival; that the mutant mice somehow
circumvent the need for it; or that the mice
were engaging in REM sleep in deeper
brain layers that the experiment did not
detect. More research is needed to tease
apart these possibilities.
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nate sleep and mood disorders in people
because REM sleep and its associated
³îx³äxlßxDäDßxî ̧øîî ̧Dx`îlxÇßxä-
sion and other illnesses. — Tim Hornyak