May 16, 2019

What's really inside that shell?

UGA scientists unlock the genetic mystery of the peanut. That’s good news for farmers.

A peanut’s shell is easy enough to crack. Its genetic code? Well, not so much. The modern cultivated peanut is actually a hybrid of two ancient species, so its genetic structure is extremely complex.

But now, that complexity has been conquered: This month, University of Georgia scientists and colleagues announced they had, at long last, mapped the genome of the modern peanut.

The resulting picture – 2.5 billion base pairs of DNA, arranged in 20 pairs of chromosomes from both ancestral species – opens the door to peanut breeders being able to alter genes within the peanut. That would make it possible to grow larger peanuts and make them better resistant to drought and insects.

The breakthrough stems from the International Peanut Genomic Research Initiative, co-chaired by GRA Eminent Scholar Scott Jackson of UGA and supported by peanut commodity groups and federal funds. The lead author of the May 2019 paper detailing the genome sequencing, published in Nature Genetics, is GRA Distinguished Investigator David Bertioli.

In recent years, both Jackson and Bertioli were key to sequencing the genomes of the peanut’s two wild ancestors. They used DNA taken from each species, which made it easier to identify how the genomes were structured and pinpoint genes that lived within them. Those successful sequencings were announced in 2016.

But the unlocking of the modern peanut genome this year was a far greater achievement. For the breakthrough to happen, it took new technology in DNA sequencing and data processing, as well as the involvement of scientists from around the world.

Plants cross-pollinate naturally, via the time-tested vectors of wind and rain, mammals and insects. But peanuts are unique. They self-pollinate, and their seeds, the nuts themselves, develop underground, making them inaccessible to the elements. 

Thus, the two peanut ancestors -- which grew in entirely different parts of the world — weren't brought together until human travelers and farmers in what is now South America did so in the earliest days of agriculture.

Today, the simple peanut is enormously important to the world. Some 46 million tons of legumes are produced on the planet every year, and as a staple crop in Africa and Asia, they’re essential to improving food security.

Closer to home, peanuts are essential to Georgia’s economy. Georgia farmers produce nearly 2 billion pounds of peanuts per year, or half the entire U.S. crop. Improving their yield means expanding what is already an $825-million a year industry – and for that, we have Georgia’s flagship university to thank. 

Read more about UGA’s historic breakthrough >