2021-01-16 New Scientist

16 January 2021 | New Scientist | 21

Palaeontology

Domestication Genetics

Tree snakes spotted

making like lassos

Snakes on the Pacific island

of Guam have been seen

moving in a new way. The

technique, dubbed lasso

locomotion, involves them

making lassos with their

lower bodies and wiggling

upwards to climb. Bruce

Jayne at the University of

Cincinnati, Ohio, and his

team recorded five brown

tree snakes using this

method to move (Current

Biology, DOI: 10.1016/j.

cub.2020.11.050).

Progeria gene

fixed in mice

CRISPR gene editing has

been used in mice to correct

the mutation that causes

the rapid ageing condition

progeria, greatly improving

the health of the animals

and doubling their lifespan

(Nature, doi.org/fp65).

The average lifespan for

children with progeria is

just 14 years.

Heat is doubly

bad for corals

Two compounding effects

hit corals as a result of heat.

Normally, they compensate

for ocean acidification, but

tests found that when the

animals are bleached by

heat stress, they become

less resilient to changes

in ocean acidity (Science

Advances, doi.org/fqdn).

Huge sharks ate

unhatched siblings

ANCIENT megalodon sharks may

have been at least 2 metres long at

birth – possibly as a result of eating

unhatched eggs in the uterus.

Kenshu Shimada at DePaul

University in Chicago and his

colleagues examined a fossil

of Otodus megalodon that was

recovered in the 1860s from

15-million-year-old rock and is

now housed at the Royal Belgian

Institute of Natural Sciences.

Studying the shark’s vertebrae

DOGS may have been domesticated

simply because our ancestors had

more meat than they could eat.

The timing and causes of the

domestication of dogs are both

uncertain. Genetic studies suggest

dogs split from wolves between

27,000 and 40,000 years ago.

It isn’t clear if domestication

happened in Europe or Asia – or

in multiple locations – or why it

occurred. One idea is that people

domesticated dogs to help them

with hunting. Another scenario has

wolves scavenging waste dumps

and getting used to people.

Maria Lahtinen of the Finnish

Food Authority in Helsinki and her

team have another idea – they think

the key was an excess of meat.

Wolves can survive on nothing

but lean meat for months. In

contrast, humans cannot. There

are limits on how much protein our

bodies can handle. Lahtinen’s team

calculated how much food was

available during the Arctic winters,

based on the prey species living

there. They found there was plenty

of lean meat, suggesting humans

would have ended up with more

than they could eat and may have

used it to feed orphaned wolf pups,

which they may have viewed as pets

(Scientific Reports, doi.org/fp6r).

Michael Marshall

allowed them to estimate its

body size at various stages in

its life (Historical Biology, DOI:

10.1080/08912963.2020.1861608).

“Megalodon’s size at birth was

about 2 metres,” says Shimada.

Similar to how a tree trunk has

annual growth rings, the shark

vertebrae has growth bands. By

counting these, Shimada and his

team suggest that this megalodon

specimen died at 46 years old.

Previous studies have relied on

evidence from megalodon teeth to

estimate body size. This is because

teeth are often the only part of a

shark to fossilise, as its skeleton is

Living cells turned

into data stores

THE DNA in live bacteria has

been edited to encode and store

information. This could be a step

towards creating a new medium

for long-term data storage.

Life’s genetic information is

held in DNA, but there is growing

interest in using it as a storage

vehicle for other kinds of data.

To do so, information is often

encoded using the four DNA

bases that make up the genetic

code. The required sequence of

bases can then be chemically

synthesised in a laboratory, and

even stored in everyday objects.

Harris Wang at Columbia

University in New York and his

team took this one step further,

using a form of CRISPR gene-

editing activated through

electrical stimulation of cells

to directly encode data through

the insertion of specific DNA

sequences. By assigning different

arrangements of these DNA

sequences to different letters, the

researchers were able to encode

the 12-byte text message “hello

world!” into DNA inside E. coli

(Nature Chemical Biology, DOI:

10.1038/s41589-020-00711-4).

Wang and his team were

subsequently able to retrieve

the message by extracting and

sequencing the bacterial DNA. LL

made of cartilage and not bone.

Studying rare vertebral remains

is critical to learning more about

ancient sharks, says Jack Cooper

at Swansea University, UK.

The large birth size suggests that

megalodon, like many present-day

sharks, ate unhatched eggs in the

uterus – known as intrauterine

cannibalism. “The consequence

is that only a few pups will

survive and develop, but each

can become large,” says Shimada.

While the growth pattern

between birth and middle age is

now clearer, we know little about

megalodon growth later in life. KS

Spare meat turned

wolves into pet dogs

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Really brief

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