RESEARCH
GENETICS
Cell type diversity
in a whole fly
The fruit fly Drosophila melano-
gaster has served as a premier
model organism for discovering
fundamental and evolutionarily
conserved biological mecha-
nisms. Combining recent
advances in single-cell sequenc-
ing with powerful fly genetic
tools holds great promise for
making further discoveries. Li
et al. present a single-cell atlas
of the entire adult fruit fly that
includes 580,000 cells and more
than 250 annotated cell types.
Cells from the head and body
recapitulated cell types from
15 dissected tissues. In-depth
analyses revealed rare cell types,
cell-type-specific gene signa-
tures, and sexual dimorphism.
This atlas provides a resource
for the Drosophila community to
study genetic perturbations and
diseases at single-cell resolution.
—BAP
Science, abk2432, this issue p. 991
NEUROGENOMICS
Mapping the brain’s
blood vessels
Cerebrovascular diseases
are a leading cause of death
and disability, but our under-
standing of the cellular and
molecular constituents of
normal and diseased human
cerebrovasculature is incom-
plete. Winkler et al. generated a
cellular-resolution atlas of the
adult human cerebrovascula-
ture. The authors used spatial
transcriptomics to reveal the
geographical organization of an
unexpectedly diverse array of
molecularly defined cell types
within the human brain. They
then explored the cellular and
molecular alterations that occur
in arteriovenous malforma-
tions, a leading cause of stroke
in young people. A specialized
subtype of peripheral monocyte
plays a role in destabilizing the
cerebrovasculature, and the
authors identified candidate
targets for therapeutic interven-
tion. —STS
Science, abi7377, this issue p. 992PLANT SCIENCE
Getting to the root
of root development
Plants have the useful abil-
ity to grow new pieces on an
as-needed basis. Omary et al.
analyzed the developmental
programs that control root
development in the tomato
plant (see the Perspective
by Shaar-Moshe and Brady).
Underground, lateral roots are
initiated from pericycle tissue
of the primary root and branch
off from the main root column.
Lateral roots can also develop
above ground, initiated off of
the aboveground shoot. These
shoot-borne roots grow from
cells associated with the phloem
that take on a stem-cell-like
state regulated by the tran-
scription factor SHOOTBORNE
ROOTLESS (SBRL). Although
belowground lateral roots and
aboveground shoot-borne
roots differ in details, their
development shares a suite
of transcription factors that
regulate a transitional cellular
state. —PJH
Science, abf4368, this issue p. 993;
see also abo2170, p. 974NEUROSCIENCE
Dopamine and the
gating of REM sleep
Sleep is composed of rapid
eye movement (REM) and
non-REM sleep, and REM sleep
usually appears after periods
of non-REM sleep. However, we
do not understand the mecha-
nisms by which the brain cycles
between these states. Using
fiber photometry, Hasegawa et
al. found increases in dopamine
activation before non-REM to
REM transitions but not before
non-REM to wake transitions in
the basolateral amygdala (seethe Perspective by Arrigoni and
Fuller). This effect was medi-
ated by dopamine receptor
D2-expressing neurons in the
amygdala. Artificially activating
these neurons induced a transi-
tion from non-REM to REM sleep
and cataplectic states in awake
mice. —PRS
Science, abl6618, this issue p. 994;
see also abo1987, p. 972ULTRACOLD CHEMISTRY
Magnetic control
of chemistry
There is a considerable inter-
est in realizing control of
molecular reactions at ultra-
cold temperatures because of
unprecedented opportunities in
the ultimate quantum regime.
Son et al. discovered an ideal
system, a sodium atom and
a sodium–lithium molecule,
in which the combination of
Feshbach resonances and low
short-range loss probability
allows for the significant sup-
pression or enhancement of
reactive collisions controlled by
external magnetic fields (see
the Perspective by Cornish and
Hutson). This work presents a
method for manipulating the
reactivity of ultracold molecules
that is qualitatively different
from previous experiments. At
the same time, this method is
highly dependent on the distinc-
tive short-range properties
offered by the sodium/sodium–
lithium complex and is subject to
further testing in other systems.
—YS
Science, abl7257, this issue p. 1006;
see also abn1053, p. 975CATA LYS I S
Ethylene extensions
Ethylene is the most common
building block of plastics, but it is
often mixed with longer carbon
chains during polymerization
to tune material properties.
Selective preparation of par-
ticular longer, terminal olefins
is therefore an area of activeresearch. Dietel et al. report
that a titanium catalyst with
optimized nitrogen-coordinating
ligands can add two equivalents
of ethylene to a terminal olefin,
extending the main chain by
two carbons while also append-
ing an ethyl branch (see the
Perspective by Rosen). The
authors attribute the selectiv-
ity to unusually rapid b-hydride
elimination. —JSY
Science, abm5281, this issue p. 1021;
see also abo1265, p. 978MAGNETISM
Magnons in a
skyrmion lattice
Electrons in two-dimensional
solids placed in an external
magnetic field fill the so-called
Landau energy levels. In materi-
als with a nontrivial spin texture,
spin excitations (magnons) may
have an analogous energy-level
structure. However, showing
this effect in an experiment is
tricky. Weber et al. used inelastic
neutron scattering and numeri-
cal simulations to demonstrate
this effect in the skyrmion lattice
phase of the material manga-
nese monosilicide. —JS
Science, abe4441, this issue p. 1025QUANTUM OPTICS
Harnessing vacuum
fluctuations
Vacuums are not simply empty
voids but rather volumes
teeming with electromagnetic
vacuum fluctuations. Although
energy conservation forbids
any process that could extract
energy from such states,
Appugliese et al. show that the
enhancement of vacuum field
fluctuations in subwavelength
split-ring resonators affects
the quantum Hall electron
transport in high-mobility two-
dimensional electron gases (see
the Perspective by Rubio). Both
the longitudinal and transverse
values of the resistance depart
greatly from their quantizedEdited by Michael FunkALSO IN SCIENCE JOURNALS
989-B 4 MARCH 2022 • VOL 375 ISSUE 6584 science.org SCIENCE