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If scientists want to track the evolutionary history of a plant,
they might turn to something like fossils.
But some scientists are using a far less traditional resource, art.
By combining it with genetic information, they can paint a picture not only of what
plants looked like back in the day, but of how and where humans grew them in
civilizations throughout history.
The idea is called art genetics, and it goes like this:
Instead of turning to scientific literature, researchers use paintings,
illustrations, or sculptures.
But not just art on its own; they combine modern
genetics with historic art.
The big advantage of art genetics is that it tells researchers something about what
the plants looked like at that point in time and not just what their genes did.
And it works particularly well for plant-based foods.
See, most - if not all - of the plant-based foods we eat today look, taste, and smell
really different from how they did when we first started domesticating them.
Their wild forms weren’t as big, tasty, or nutritious as the
domesticated kinds we have today.
Like, take a look at this watermelon from the 1600s.
Lots of white rinds, big seeds, and not much juicy flesh.
Those wild forms slowly changed thanks to a process called artificial selection,
where humans breed a species for a specific trait.
In the case of melons, we picked
and bred plants with fruits that had smaller seeds,
fewer thorns, or just tasted sweeter.
Over time, the genes linked to those physical traits
became more common in the plant population.
And by tracking changes in plants and how they spread throughout the world,
researchers can pinpoint their role in past cultures, economies or trade.
Take the humble potato for example.
In areas of ancient South America, those who
controlled the potato trade controlled the land.
The ancient Moche people would not only eat this
terrific tuber but make pottery out of it.
That pottery survived for thousands of years, and by seeing where it crops up, we
can track the rise and fall of this and other ancient civilizations.
Now, if you don’t happen to have potato pottery on hand, there are a couple of
other ways you could turn back the clock and see what crops used to look like,
though they do each have their pros and cons.
First researchers could look for remains of crops, things like seeds or fruits, or
traces of DNA, an approach called archaeobotany.
Basically, looking for plants like you would look for, say, dinosaur fossils.
It’s a pretty useful method from the DNA side of things.
For example, scientists have used archaeobotany to uncover where ancient cereal
grains were grown and map changes in the size of
rice grains from sites in India and China.
But it also has its drawbacks.
Archaeobotany is pretty time-consuming because researchers have to spend their
time hunting through massive archeological sites all over the world.
Literally looking for grain in a massive archeological haystack.
And just like the squishy bits of dinosaurs or other animals, the colorful plant bits,
like the flesh or rind, don’t tend to stick around too well.
So another approach is to study plants through ancient writing.
Texts stick around a little better because of the way people preserved and cared for
them or because they made copies.
And those texts can tell researchers something about
how the crops were used culturally, like in cooking.
But although literature might tell researchers how plants were
used in a recipe, it usually won’t tell you anything about what the crop looked like.
So paintings or visual media might be the way to go.
After all, paintings predate modern written language,
archeological techniques, and modern genetics.
The oldest cave paintings of plants date back to around 25,000 years ago,
and even more detailed paintings, like these of fruits from ancient Egypt,
are more than 3,000 years old.
Plus, the “database” of plant-based foods researchers can draw from is huge.
Especially if you consider paintings, illustrations, sculptures, iconography,
there’s a lot.
And almost every civilization across the world creates and has created art,
so the database of information isn’t limited to, say,
favorable soil conditions that might preserve a seed or bit of grain.
But to use art as a scientific resource, you have to get around artistic liberty.
For example, if researchers used Hieronymus Bosch’s painting
“The Garden of Earthly Delights” to decide what strawberries looked like,
they might have gotten some pretty wild ideas if they were
taking the painting at face value.
Like, that strawberries used to be person-sized.
One way to get around this is by cross-referencing the
painting with another artwork by the same artist.
Which wouldn’t really work for Bosch, since his fruit seemed to
represent an abstract concept and so was often overblown in size or style.
But you might be able to cross-reference with
other artists from around the same period.
So you could refer to Vertumnus by Giuseppe Arcimboldo,
which was painted around the same time as Bosch’s work.
Although it’s a unique way to paint a portrait, the fruits
themselves are pretty regular-looking.
Or, researchers could discount certain artists or works of art altogether if there’s
evidence that they tended to depict things in fantastical ways.
Which might be wise in Bosch's case!
Essentially, researchers could “screen” particular
artists or artworks for their authenticity.
But if they saw a certain feature popping up over and over again,
it might give them a reason to suspect that that’s actually what a crop looked like.
Take Pieter Aertsen’s work The Vegetable Seller from 1567, for example.
Like other paintings by Dutch artists around that time, it shows carrots in many
different colors, orange, white, purple, and even red.
But look at later paintings by Aertsen and others,
and you’ll notice mostly orange carrots.
Scientists have actually used those paintings as a starting point
for tracking carrot evolution in combination with modern genetic techniques.
They found that the modern orange variety was cultivated in
The Netherlands at the time of the agricultural revolution.
A commentary published in 2016 in the journal Trends in
Plant Science matched up the timeline of carrot paintings to work that geneticists
had done over the years on the genes responsible for carrot color.
The color comes from two biological pathways that make pigments called
carotenoid, mostly orange, and anthocyanin, purple.
By breeding orange carrots with more orange carrots,
Dutch horticulturalists were selecting for a form of a gene
called Y2 that allowed that orange carotenoid pigment to build up,
making the distinct orange we see today.
Another example is the watermelon.
Up until a few years ago, botanists weren’t
sure where and how exactly watermelons were domesticated.
Ancient, undomesticated watermelon varieties were white, bitter,
or bland tasting.
All around, not very nice.
It’s thought that there were some small, sweet versions
out there, mostly in central Sudan.
But when the sweet, red watermelon that we know today
first cropped up was a bit of a mystery.
Over the years, researchers have been finding more and more
DNA evidence that has allowed them to reconstruct an
evolutionary history of the genes that dictate color or taste.
DNA evidence from a watermelon leaf in an ancient Egyptian
tomb led researchers to conclude that the ancient Egyptians were one of the first to
domesticate the sweet, red watermelon variety some 3,500 years ago.
Sequenced DNA showed that the leaf from the tomb
was the sister watermelon variety to the sweet, Sudanese kind.
The researchers also saw that there was a little
sequence of DNA plonked in the middle of a
particular gene that codes for bitterness.
That little chunk of the sequence, also called a stop
codon, stopped the bitter gene from being expressed.
In other words, it stopped the melon from being bitter.
And what’s more, the Egyptian watermelon had a gene
that codes for the watermelon’s characteristic red color.
And, by looking at wall paintings from tombs in nearby regions of Egypt, from
around the same time, they could actually see what those
watermelons looked like and confirm their genetic findings.
The melons looked quite a lot like the watermelons we have today.
Long, with those characteristic white stripes down the length of them.
The melons were also painted lying on a tray, which made researchers think the
fruits might have been eaten raw and, therefore, were sweet.
Although the ancient Egyptians were one of the first to cultivate the fruit,
researchers now think that watermelons were domesticated at least three times,
once in Africa and twice in India.
And, if you look at paintings of melons from around the world,
you can see when the domesticated,
sweet varieties popped up in different regions.
So by combining art with genetics, scientists can understand both what plant foods
looked like and the biological mechanisms that made them look like that.
Which is pretty cool!
And what’s even cooler is that you can contribute!
Researchers are trying to put all this artistic information
together into a massive, searchable database.
See, museum databases are awesome at cataloging work,
but they don’t always include information on what’s pictured in the artwork.
The artwork names can be totally vague, like still life.
So instead, researchers David Vergauwen, an art history lecturer,
and Ive De Smet, a plant biologist, are asking people to take pictures of artwork.
Not just artwork presented in museums,
but ones in private collections, mansions, or even castles.
You can then send the picture in with a description
of what’s in the painting, the artist’s name, and the date it was made.
And it’ll all appear in an online database for everyone to use!
So you can get snapping and send your pictures to
ArtGeneticsDavidIve@Gmail.com
And you’ll be contributing to a brand new frontier of science.
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