Science - USA (2022-04-15)

at the regional level may shape

institutionalized practices that

motivate police officers to mis-

treat Black drivers. —EEU

Psychol. Sci. 1 0. 1 1 7 7/

09567976211051272 (2022).

EXTREME PRECIPITATION

Overlook not the weak

Although extreme rainfall typi-

cally is thought of as being the

result of dramatic storms with

intense convection, it also can

accompany weak convection

events. Xu et al. used satellite

data from 1998–2014 to show

that these weakly convecting

extreme precipitation events

are as frequent as ones with

strong convection globally, each

type making up nearly one-

third of the total over land. The

authors compare and contrast

the relative contributions of the

two types of extreme rainfall

regimes and their geographic

distributions and discuss the

differences in their dynamic

structures and storm environ-

ments. These insights should

help to improve both our

260 15 APRIL 2022 • VOL 376 ISSUE 6590 science.org SCIENCE

RESEARCH | IN OTHER JOURNALS

RACIAL DISPARITY

Institutionalized

prejudice

Findings that Black drivers in the
United States are disproportion-
ately stopped by police officers
are well documented. However,
understanding what motivates
racial disparities in traffic stops
has challenged researchers.
Such disparities in police activity
could arise from individual police
officers’ racial animus or they
may be due to widespread racial
bias across the communities
in which officers work. Stelter
et al. connected research on
intergroup bias with policing
data and examined more than
130 million traffic stops across
1413 US counties. They found
that higher levels of racial bias
among white Americans at the
county level was associated with
more traffic stops of Black driv-
ers. These results indicate that in
addition to reducing bias among
individual police officers, future
interventions should account
for a larger social context.
Prejudice among white residents

theoretical and observational

understanding of extreme rain-

fall events. —HJS

Geophys. Res. Lett. 49 ,

2022GL098048 (2022).

SYNTHETIC BIOLOGY

Plant control of

mammalian cells

The clever use of a signaling

system borrowed from plants

allowed investigators to design

a synthetic circuit that con-

trols the size of a population

of mammalian cells. Ma et al.

put elements of the signaling

system for the plant hormone

auxin into mammalian cells

so that they would produce

and detect a signal to monitor

population size that did not

overlap or interfere with endog-

enous signals. The authors also

designed the circuit to catch

and destroy “cheater” cells that

developed mutations, allowing

them to escape regulation. Such

population control is an impor-

tant goal for synthetic biology

applications aimed at potential

therapeutic applications in

humans. —LBR

Cell 185 , 967 (2022).

SUPERCONDUCTIVITY

An unexpected

asymmetry

In the physics of cuprate super-

conductors, the compounds with

the highest transition tempera-

tures (“optimal”) and those with

less than optimal doping (“under-

doped”) tend to have the most

exotic properties. “Overdoped”

cuprates, by contrast, are thought

to be more conventional. Zou

et al. used scanning tunneling

microscopy to study the tunnel-

ing spectra in several overdoped

bismuth-based cuprates. The

researchers found an asymmetry

between the positions of particle

and hole coherence peaks, an

unusual finding in a supercon-

ductor. These findings may have

implications for how super-

conductivity disappears in the

transition to a metallic phase. —JS

Nat. Phys. 10.1038/s41567-022-

01534-x (2022). PHOTO: SIMON SHIM/SHUTTERSTOCK

Several dipteran flies, including the

fungus gnat shown here, have accessory

chromosomes in their germlines.

GENOMICS

Gene-rich germline

S

omatic cells may not necessar-

ily contain complete genomes.

Several taxa, from songbirds to

worms, show germline-restricted

DNA, which may comprise entire

or partial chromosomes [germline-

restricted chromosomes (GRCs)].

Families of small dipteran flies are par-

ticularly rich in examples, many of which

show different mechanisms for somatic

tissue chromosome elimination. Hodson

et al. assembled the genome of the

fungus gnat (Bradysia coprophila) and

sequenced germline and somatic tissue

to find out more about this “acces-

sory” DNA. This polyploid gnat has two

large GRCs that are packed with genes

bearing more resemblance to those

of another distant family of Diptera.

This finding points to acquisition by

an ancient hybridization event, but we

can only speculate why the accessory

chromosomes are retained. —CA

PLoS Biol. 20 , e3001559 (2022).