Natural GMOs Part 279. The peanut comes from inter-species DNA shuffling ages past
...The mother of peanut
Using the new genome
sequence as a framework, the team was able to analyze the variations in more than 200 of the most diverse peanuts from all of over the world. Researchers found characteristic genetic fingerprints shared by all the peanut plants tested, providing new evidence that all modern peanut varieties stem from the same original hybrid.
Soroya Bertioli inspects peanut plants at the UGA Institute for Plant Breeding, Genetics and Genomics greenhouse.
“The new study underlines how peanut’s origin was due to very special circumstances thousands of years ago. Ancient farmers transported one species into the range of another, allowing their hybridization and the formation of a new crop species,” said Soraya Leal-Bertioli, a senior research scientist with the UGA Institute of Plant Breeding, Genetics and Genomics and the CAES department of plant pathology.
Scientists with the initiative had previously found the male donor of the original hybrid and origin of peanut’s “B” subgenome. In this new study they identified the female donor, tracking the population of wild ancestral peanut that contributed the peanut “A” subgenome in Rio Seco, Argentina. These individuals form the “mother” population of peanut.
But the evidence that all modern peanuts can be traced to a single original hybrid sets up another mystery, Leal-Bertioli said. How does a plant with such a narrow genetic base develop so many variations and varieties?
Most flowering plant species rely on animals or weather to spread their pollen or seeds to other plants to generate genetic diversity. Pollen and seeds can travel for miles, spreading newly occurring traits to new populations.
But peanuts, which produce their seeds underground, don’t do that. It took early human farmers and their long-distance transport of seeds to get the first two ancestral peanut parents together.
Since then, however, the plant has used a new mechanism for creating diversity.
The peanut has two sets of chromosomes, one from each ancestor. By analyzing more than 200 cultivated peanuts from all over the world, it was shown that different landraces and cultivars have shuffled the genetic material of the ancestors and deleted some sections altogether. Over the past the 10,000 years, this shuffling has happened thousands of times — allowing a much faster-paced generation of diversity than if the plants simply relied on mutation.
In a greenhouse on the UGA campus, the Bertiolis have worked with hybrids that re-create the original ancestral peanut and observed the shuffling in real time. They documented its effects in the spontaneous appearance of different flower colors. These same genetic mechanisms generate other types of variation as well, said David Bertioli.
The phenomenon explains the tremendous about of diversity seen in peanuts today, said Leal-Bertioli.
For this research the International Peanut Genome Initiative brought together scientists from the U.S., Argentina, China, India, Japan and France. The initial sequencing
was carried out at the Hudson Alpha Institute, Huntsville, Alabama, and USDA Agricultural Research Service Genomics and Bioinformatics Research Unit in Stoneville, Mississippi. The project was funded by the National Peanut Board, the American Peanut Shellers Association, and other growers, shellers, manufactures and allied industries.
Original Article: Natural GMOs Part 279. The peanut comes from inter-species DNA shuffling ages past
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