12 September 2020 | New Scientist | 43“I’m confident that the new data would be
taken very seriously by most,” says William
Jungers at Stony Brook University, New York,
but he adds that it probably wouldn’t be seen
to override all of the evidence gleaned from
the shape of the fossil bones themselves.
That’s probably a good thing as molecular
information isn’t infallible, says John Hawks
at the University of Wisconsin-Madison.
For instance, he recalls that when geneticists
first looked at segments of Neanderthal DNA
in the late 1990s, they concluded that our
species didn’t interbreed with Neanderthals,
which we now know is incorrect.
But although some caution is required,
ancient proteins are almost certain to be one
of the next big things in human evolutionary
studies. Assuming the work on H. naledi
goes ahead successfully, there is potential
to recover proteins from far older fossils.
Already, Welker and his colleagues have
extracted them from a 1.9-million-year-old
H. erectus tooth. They were too degraded to
be useful, although Welker says that might be
because the tooth in question was damaged,
meaning some of the proteins it originally
contained might have leached out.
Collins says it could even be possible
to extract proteins from the ape-like
hominins that came before humans,
and use the information to work out how
some of them relate to each other and to
us. That might seem far-fetched – but in
2016, Collins was involved in a study that
successfully extracted proteins from ostrich
eggshell fragments collected at Laetoli,
a 3.8-million-year-old site in Tanzania
world famous for preserved footprints
left by a Lucy-like hominin.
“We have such an interesting family tree
with some curious critters in there,” says
Collins. “But I’m pretty sure the protein
work will be able to put some of them
on the right evolutionary branch.” ❚Colin Barras is a New Scientist
consultant based in Ann Arbor,
MichiganExtracting insights
into ancient lives
As we get better at reading
the information they contain,
ancient protein fragments
are telling us about how our
ancient ancestors behaved.
For instance, Neanderthals
who lived in southern France
during the Stone Age
typically hunted reindeer. But
earlier this year, an ancient
protein analysis by Naomi
Martisius at the University
of California, Davis, and her
colleagues revealed that
the ancient humans chose
to make their bone tools
from the ribs of aurochs
and bison, although these
animals were less common.
Studying ancient proteins
can also throw new light
on recent human evolution.
Earlier this year, Shevan
Wilkin at the Max Planck
Institute for the Science of
Human History in Germany
and her colleagues examined
food proteins trapped in
ancient dental plaque. They
concluded that people on
the eastern Eurasian steppe
began consuming dairy
produce at least 5000 years
ago. This means there is an
equally long history of dairy
consumption in Europe and
on the Eurasian steppe. And
yet, while many Europeans
now carry a genetic
adaptation that makes
digesting milk easier for
adults, few people on
the Eurasian steppe do.
“These two regions seem
to take these different
trajectories when it comes
to evolutionary selection
for dairy consumption,
and it’s so interesting to
ask why,” says Jessica Hendy
at the University of York,
UK, a co-leader of the study.
It is a question she is now
eager to answer.
Ancient proteins can
even guide us to a better
understanding of prehistoric
sex lives. One of the biggest
science stories of 2018
was the discovery that
a 90,000-year-old bone
fragment belonged to a
teenage girl – nicknamed
Denny – who had a
Neanderthal mother and
Denisovan father. Although
it was DNA analysis that
revealed Denny’s remarkable
parentage, geneticists might
not have chosen to study the
bone fragment if not for the
fact that ancient proteins had
already shown it belonged to
an ancient human.Researchers
can use mass
spectrometers
to analyse
ancient proteinsLE
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