Wheat Genome Mapped

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Photo by Getty Images/ithinksky
Wheat has been a notoriously challenging genome to sequence.

Genetic research unveils new truths about the natural world every year, but some genomes are notoriously difficult to crack. A small U.S. research team has finally succeeded in unlocking wheat’s DNA, a challenge that many crop geneticists considered almost insurmountable.

The genetic complexity of wheat (Triticum aestivum) meant that it took more than a decade of global effort before the genome was successfully mapped. Between 16 and 17 billion individual nucleotides compose wheat’s DNA, and most of its genome is made up of repeating sequences that make it difficult for scientists to identify meaningful patterns using traditional DNA sequencing techniques. Likewise, a single copy of this DNA is more than five times the size of the human genome, and it contains six copies of every chromosome.

Though the genome had previously been partially sequenced, significant gaps in the data made it difficult to interpret. To fill in the gaps, the research team used two forms of innovative technology to generate both short, highly accurate DNA sequences and sequences as long as 10,000 nucleotides, allowing the team to match the short sequences against the longer sequences for a more accurate composite sequence. These sequences totaled almost 15.3 billion nucleotides, or about 90 percent of the genome.

The impacts of this breakthrough go beyond scientific curiosity. Wheat is a staple crop that more than 2 billion people rely on each day, and a better understanding of its genetics will aid efforts to improve its growth in extreme conditions, such as drought or flooding. Likewise, this small team of scientists’ success in cracking such a complicated genetic sequence bodes well for faster breakthroughs in future genetic research.

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