Century-old genetics mystery of Mendel's peas solved

Summary

Gregor Mendel cross-bred some 28,000 garden pea plants (Pisum sativum) and studied traits such as their flower colour to make discoveries about genetic inheritance.Credit: imageBROKER/AlamyThe Augustinian friar Gregor Mendel completed his groundbreaking work on genetic inheritance more than 160 years ago, after carefully studying seven traits in peas, including the shape and colour of their seeds and pods. Yet until now, scientists still hadn’t worked out which genes drive three of those traits in the garden pea (Pisum sativum).In a paper published on 23 April in Nature1, researchers add a fresh chapter to Mendel’s pivotal story, perhaps in the process launching a new era in the genomic study of peas, which are a popular source of plant-based protein.Scientists published a reference genome for P. sativum in 20192. That digital sequence — a representation of the plant’s DNA — “was a huge breakthrough”, says Clare Coyne, an adjunct plant geneticist at Washington State University in Pullman. “But I would say [the latest study] is an even larger breakthrough. It’s really just an incredible effort.”Modern tools meet age-old mysteryMendel, a citizen scientist, famously performed a series of experiments in the mid-nineteenth century in which he cross-bred some 28,000 pea plants to understand how their traits were inherited by future generations. Although at that stage the concept of genes didn’t exist, Mendel concluded that plants were passing along hereditary ‘factors’ to offspring that determined whether they inherited what turned out to be ‘dominant’ or ‘recessive’ versions of genes known as alleles. Scientists continue to study such Mendelian traits today, and have identified thousands of them in humans. However, many of these traits have yet to be linked to a particular gene — and the same had been true of three of Mendel’s original seven pea traits.Mendel, a friar, is recognized today as the founder of genetics.Credit: Pictorial Press/AlamyNoam Chayut, an applied cro...