Loblolly sets record for biggest genome

Sequence of pine tree’s DNA surpasses the base pairs of wheat

GENE GIANT  The loblolly pine has the biggest set of genetic blueprints ever published.

David Stephens/Bugwood.org

A giant among trees, the loblolly pine boasts the largest set of genetic blueprints published to date. Even though it’s big on DNA letters, the pine’s instruction book lacks originality: About 82 percent is made of repeating DNA elements.

Researchers first reported deciphering loblolly’s roughly 22 billion letters, or bases, at a conference in 2013 (SN Online: 5/16/13). Now, the team has provided analysis of the loblolly genome in three papers, two in the March issue of GENETICS and one in Genome Biology. Loblolly (Pinus taeda) took the title of largest genome away from wheat, which has 17 billion base pairs.

The conifer can grow to 30 meters tall and is the source of most paper products in the United States. The new results reveal several spots in the pine’s genome that are linked to resistance to pathogens. Continuing to study those regions could help scientists understand how loblollies and other pines battle disease.

Ashley Yeager is the associate news editor at Science News. She has worked at The Scientist, the Simons Foundation, Duke University and the W.M. Keck Observatory, and was the web producer for Science News from 2013 to 2015. She has a bachelor’s degree in journalism from the University of Tennessee, Knoxville, and a master’s degree in science writing from MIT.

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