Sweet Potato DNA Decoded, Reveals Ancestry

For decades, the sweet potato, a vital crop for millions, has kept its genetic secrets due to its complex genome. Unlike humans, who have two sets of chromosomes, sweet potatoes have six, a condition called hexaploidy, which made decoding its DNA an immense challenge. A team of scientists at the Boyce Thompson Institute, led by Professor Zhangjun Fei, has finally decoded the complete genome of a sweet potato variety called 'Tanzania,' known for its disease resistance.

Published in Nature Plants, the study used advanced DNA sequencing to untangle the plant's 90 chromosomes and separate them into their six original sets. This groundbreaking achievement provides an "unprecedented level of clarity," according to Fei.

The research revealed that the sweet potato's DNA is a mosaic of multiple wild ancestors, some of which have yet to be identified. One-third of its genome comes from Ipomoea aequatoriensis, an Ecuadorian wild species, while another portion resembles a Central American species called Ipomoea batatas 4x. The ancestral genetic sequences are uniquely intertwined on the same chromosomes, which makes the plant highly adaptable and resistant to disease.

This intertwining of genetic material, along with its six sets of chromosomes, is key to the sweet potato's remarkable resilience. The multiple copies of important genes act as backups, helping the plant withstand drought, pests, and other environmental stressors, a feature known as polyploid buffering.

For more details, read the news article on the Boyce Thompson Institute website.