The iconic monkey flower’s genome harbors “hot spots” of genetic exchange
By analyzing the genomes of a wild population of Mimulus guttatus, also known as the monkey flower, researchers were able to pinpoint “hot spots” in the plant’s DNA code (http://www.jgi.doe.gov/News/news_13_11_18.html with high rates of gene-shuffling recombination. They also provided a reference genome for the plant.
For decades, its varied morphology and easy breading has made Mimulus an ideal model for plant genetics. The findings will likely influence future plant-breeding strategies and the reference genome will likely lead to an explosion of studies of this plant’s genome structure, as seen with poplar and soybean
Plants of the Mimulus genus are named for their characteristic flowers that resemble a scrunched-up monkey face. A near cousin to the oft-domesticated snapdragon, the plant’s flowers often sport “bee lines” to guide pollinators. The research team, led by the U.S. Department of Energy (DOE) Joint Genome Institute (JGI), took samples from a wild population of Mimulus guttatus located within a 16-km radius in the Sierra Nevada foothills of Northern California, one of the worldwide centers of biodiversity for Mimulus species and known for the diverse habitat of the plant and the sizes,shapes and colors of the plants themselves. The findings, published the week of November 11, 2013 in the journal Proceedings of the National Academy of Science (PNAS), characterized the evolutionary history of Mimulus. The team charted roughly traced some 400,000 genetic cross-over events (incidents of genetic shuffling) in this single population, exploiting Mimulus’s high count of SNPs (single nucleotide polymorphisms). They identified “hot spots” where many more gene swaps happened and “cold spots” that rarely saw any changes to the genetic code that were passed down unaltered from parents to progeny. Moreover, the team could identify the hot spots with an extremely high degree of resolution. They found that these hot spots could be classified in terms of the rate of genetic shuffling.
There were many “lukewarm” regions, but also some rare “steaming hot” regions. Compared to other organisms, Mimulus had a much higher rate of genetic changes, averaging one nucleotide base change (one letter in the genetic code) for every 35. Humans only have one nucleotide base change in 1,000. “With this reference, we’ll be extending Mimulus’ role as an important genetic model to gain additional insights that should be generally applicable to many plants, ultimately helping with crop improvement strategies for important agricultural and biomass-for-biofuels crops,” said Uffe Hellsten, the first author on the paper. The Mimulus guttatus draft genome is publicly available at the DOE Joint Genome Institute’s plant data repository, Phytozome: http://www.phytozome.net/mimulus.php.
Uffe Hellsten UHellsten@lbl.gov DOE Joint Genome Institute
U.S. Department of Energy, Office of Science
Uffe Hellsten et al, Fine-scale variation in meiotic recombination in Mimulus inferred from population shotgun sequencing. PNAS November 13, 2013 e-pub ahead of print doi:10.1073/pnas.1319032110