March 30, 2012

Van Gogh Painted Mutant Sunflowers

For more than a century, Vincent Van Gogh's series of paintings depicting overly-bushy sunflowers were thought to be the result of his alleged mental illness at work, but now could actually be realistic impressions of a genetic mutation seen in some strains of the flowers, according to a new study.

Most typical sunflowers have a brown, seed-filled middle and a single ring of yellow petals. But some seem overgrown with double rows of petals -- like the "Teddy Bear" variety -- and others have scrawny petals and seeds extending almost to the edge of the flower, the results of genetic mutations.

Published in the March 29 issue of the journal PLoS Genetics, the study reveals Van Gogh's work may have actually been based on real-life mutations he was observing when painting the pieces.

"In addition to being of interest from a historical perspective, this finding gives us insight into the molecular basis of an economically important trait," study researcher John Burke, of the University of Georgia, told MSNBC in a statement. "You often see ornamental varieties similar to the ones Van Gogh painted growing in people's gardens or used for cut flowers, and there is a major market for them."

Sunflower heads are actually a multitude of small flowers -- called florets -- that have a very specific symmetry. In a normal sunflower, the outer florets sprout into petals and the inner ones mature into seeds.

Burke and his colleagues, hoping to gain a clear understanding of the genetic basis of the differences, began creating their own sunflower babies that were a mixture of regular sunflowers and a variety of bushy ones. In doing so, they found that a single, dominant gene was responsible for bushy flowers like the ones seen in Van Gogh's impressions.

To make sure they were getting accurate results, they double-checked their findings, and then sequenced the gene and looked for it in several commercially available types of sunflowers. They never saw the mutation in flowers that had the traditional sunflower appearance, but always saw it in the fluffy ones.

The newly discovered mutation changes how the plant regulates where the line between "petals" and "seeds" is drawn. When mutation occurs, the gene can move the boundary either closer to the center of the flower head, or farther away from it. If the boundary line moves toward the center, the flower loses its traditional "sunflower" look and resembles the "Teddy Bear" sunflower. If it moves outward, more seeds are created with shorter petals.

"All of this evidence tells us that the mutation we've identified is the same one that Van Gogh captured in the 1800s," said Burke.

The research was funded by the Gloeckner Foundation Floriculture Grants Program and the National Science Foundation.


On the Net: