The sweet potato feeds millions worldwide, especially in sub-Saharan Africa, where its natural resilience to climate extremes makes it crucial for food security. But this humble root vegetable has guarded its genetic secrets for decades. Now, scientists have finally decoded its complex genome, revealing an intricate origin story and providing powerful tools to help improve this vital crop.

Sweet potato DNA is extraordinarily complex. While humans have two sets of chromosomes, one from each parent, sweet potatoes have six. This condition, called hexaploidy, made deciphering their genetic code like trying to reconstruct six different, yet similar, sets of encyclopedias that have been shuffled together.

A team led by Professor Zhangjun Fei at the Boyce Thompson Institute achieved a significant breakthrough, as reported in Nature Plants. Using cutting-edge DNA sequencing, along with other advanced techniques, they created the first complete genetic makeup of “Tanzania”—a sweet potato variety prized in Africa for its disease resistance and high dry matter content.

The central challenge was to untangle the plant’s 90 chromosomes and organize them into their six original sets, called haplotypes. The team succeeded in fully separating (“phasing”) this complex genetic puzzle, something that had never been achieved before.