Sequencing hundreds of chloroplast genomes

Researchers at the University of Florida and Oberlin College have developed a sequencing method that will allow potentially hundreds of plant chloroplast genomes to be sequenced at once, facilitating studies of molecular biology and evolution in plants.

The chloroplast is the compartment within the plant cell that is responsible for photosynthesis and hence provides all of the sugar that a plant needs to grow and survive. The chloroplast is unusual in containing its own DNA genome, separate from the larger and dominant genome that is located in every cell's nucleus.

Chloroplast DNA sequences are widely used by plant biologists in genetic engineering and in reconstructing evolutionary relationships among plants. Until recently, though, chloroplast genome sequencing was a costly and time-intensive endeavor, limiting its utility for plant evolutionary and molecular biologists. Instead, most researchers have been limited to sequencing a small portion of the chloroplast genome, which in many cases is insufficient for determining evolutionary relationships, especially in plant groups that are evolutionarily young.

In contrast, complete chloroplast genome sequences harbor enough information to reconstruct both recent and ancient diversifications. New DNA sequencing technologies, termed "next-generation" sequencers, have made it considerably cheaper and easier to sequence complete chloroplast genomes. While current methods using next-generation sequencers allow up to 48 chloroplast genomes to be sequenced at one time, the new method will allow potentially hundreds of flowering plant chloroplast genomes to be sequenced at once, significantly reducing the per-sample cost of chloroplast genome sequencing.