In 2017, the Smithsonian Magazine published a curious article, from which it appears that modern apple’s evolution roots out from the Silk Road.

In the year 2010, a cadre of scientific explorers delving into the genetic secrets of the domestic apple, Malus Domestica, uncovered a realm of astounding complexity. Within its spiraling DNA, they found approximately 57,000 genes—a number towering over any plant genome previously encountered, and thrice that of humans, who boast a mere 19,000. This scholarly odyssey also cast light on the apple’s lineage, tracing its noble blood back to the wild Malus sieversii.

Recently, in a study published in the esteemed journal Nature Communications, these researchers ventured further into the apple’s genetic labyrinth. They meticulously sequenced the genomes of 117 apples—domestic, crab, and wild—from 24 diverse species. Their quest was to unravel the intricate tapestry of evolution that led to the apples of today—from the tart Granny Smiths to the crisp Honeycrisps. The Silk Road, that ancient artery of commerce and culture, emerged as a pivotal thread in this narrative.

According to the researchers, two distinct populations of Malus sieversii have been identified—one in China’s Xinjiang region and the other west of Kazakhstan’s Tian Shan mountains. Yet, the cultivated apple, it seems, springs solely from the Kazakh lineage. As traders journeyed along the Silk Road, they feasted on these apples, sowing their seeds intentionally or discarding cores along the way. The progeny of these seeds intermingled with local crabapple species, weaving a new genetic tapestry. The Malus sieversii contributed size and allure, while the crabapple lent firmness and a tangy zest to the fruit.

In a parallel eastward journey, the Kazakhstan apples blended with other species, birthing the soft, sweet dessert apples now found in China. «The traders traversed the Eurasian expanse in both directions,» explains study co-author Yang Bai, «scattering those ancestral seeds in their wake.»

Through time, human hands began shaping the apple’s destiny, selecting and nurturing them for specific flavors and traits. This led to the flourishing of 7,500 apple varieties, each with its unique charm—some ideal for baking, others for cider-making, and many simply perfect for a joyful crunch.

The study illuminates that about 46 percent of the domestic apple’s genome hails from the Kazakh Malus sieversii, with 21 percent from the European crabapple, Malus sylvestris. The remaining 33 percent is shrouded in mystery. Despite their genetic dominance, modern apples share more in taste and texture with crab apples than their Kazakh ancestors. «The Malus sieversii, though larger than other wild apples, are soft and bland, often unappealing to the palate,» notes Bai.

This trove of genomic knowledge is a beacon for apple breeders, guiding them towards crafting larger, juicier, and more resilient apples. The Xinjiang Malus sieversii, untouched by domestication’s hand, may harbor traits to further refine the apple. «These apples, overlooked in domestication, are a hidden gem in Xinjiang,» says Bai.

Moreover, this research paves the way for targeting genes to enhance apple size. Bai teases a future where, in an extraordinary twist, apples might rival watermelons in size, heralding an era of grander pies and bounteous harvests.