Researchers Sequence Pepper Genome

Researchers from Sichuan Agricultural University in China have sequenced the genomes of wild and domesticated peppers and found that more than 81% of the pepper genome consists of transposons, or "jumping genes" that change position within the genome. These transposons probably were responsible for the pepper's great degree of genetic diversity.

Pepper belongs to the Solanaceae family, which also includes tomato, potato and eggplant. To gain a better understanding of pepper evolution, the team led by Cheng Qin generated and analyzed the genomes of two types of peppers: a cultivated pepper known as Zunla-1, and its wild ancestor, Chiltepin. The team found that most of the transposons in the pepper appeared about 300,000 years ago and concluded that pepper's genomic expansion would have begun then. They also found that the Solanaceae family first appeared almost 156 million years ago, and the pepper diverged from the tomato and potato about 36 million years ago. Qin's team was able to identify genes associated with seed dormancy, disease resistance and the ripening process, which affects shelf life. The researchers also identified the genes that affect the synthesis of capsaicin, the chemical that makes pepper spicy.

The results of the study appeared in the Proceedings of the National Academy of Sciences, and the abstract is available at: http://www.pnas.org/content/early/2014/02/26/1400975111.abstract.