Ehh, what’s up doc?

Down the Rabbit Hole - Carrots, Genetics and Art

KAR

On May 2016

Scientists unveiled the full carrot genome sequence!

32,000 genes were discovered!!

10.9 Impact Factor (2015)

Paper tries to explain how art

can help us understand the science and evolution of carrot

Why are orange carrots, orange?

The Mighty Carrot• Origin of the Carrot

• Carrots and Art

• Genetics of Carrot Colors

Origin of the Carrot

… is complex!!

Carrot originated 5000 years ago in Central Asia!(Vavilov, 1951)

Temple drawings from Egypt in 2000 BC show a purple plant

1st domesticated around 900 AD

1st domesticated around 900 AD

Yellow, Purple and Whitecarrots

10th century Cookbook

By 14th century, carrot spread throughout Europe

Carrots back then were yellow, purple and white

Carrots and Art

What does Art has got to do with the science of Carrots?

Paintings can help us understand the evolution of cultivated plants

Accuracy depends on the artist’s skills / interpretations

‘Realistic’

Joachim Beukelaer (1534 – 1574)

Requires interpretation

Egyptian mural

So The Story Goes…

• In the 1950’s, Otta Banga (Dutch agronomist)

• Visited the Louvre in France and other museums in Netherlands

Pieter Aertsen, Christ in the Home of Mary and Martha, 1553

Pieter Aertsen, After the harvest , 1567

Pieter van Rijck, 1610 

De groentewinkel, Jan Victors, 1654

Where do carrots come from?

…and he somewhat became obsessed with carrots

Late 16th Dutch Golden Age paintings - Colourful carrots

Late 17th century paintings - Orange carrots mostly

What did Banga noticed about the paintings?

Orange carrot appeared in late 16th to early 17th century

Dutch “invented” orange carrots

What did Banga hypothesized?

16th century, Orange carrots came from yellow

varieties

‘spontaneous action’

Genetics of Carrot Colors

Carrots have not always been orange

Carrots come in various colors!

Why are orange carrots, orange?

Two pathways control carrot color

Carotenoid biosynthesis

Anthocyanin biosynthesis

YY2 Gene Model

Phenotypicdifferences

Dominant Y allele

Dominant Y2 allele

Chromosome 5

Chromosome 7

Inhibits carotenoid

accumulation

Target gene during C17th

selection

Y locus

Y2 locus

allele 1 Y

y allele 2

Homozygous YY

Heterozygous Yy

Homozygous yy

Y Y Y Yy y y y

Researchers found new ‘star’ gene that leads

to carotenoid biosynthesis

Precursor Gene

Overexpression

Precursor Gene

Overexpressed

Precursor Gene

Overexpressed

Precursor Gene

Overexpressed

Precursor Gene

Overexpressed

Y2 gene

Zeaxanthin Epoxydase

(ZEP)

Precursor Gene

Overexpressed

Y2 gene

Zeaxanthin Epoxydase

(ZEP)

Carotenoid accumulates Taproot

• Color had important role in the history of carrot domestication

• Early paintings / illustrated manuscripts hold important clues to carrot color breeding

• Genetics could unravel the mystery of the color of carrots

"Now we have the chance to dig deeper and it's a nice addition to the toolbox for improving the crop."

Phil Simon, PhDHorticulture Professor / GeneticistLead Researcher for The Carrot Genome ProjectUniversity of Wisconsin-Madison