Mendel’s garden: Czech scientists play key role in global project mapping pea genome

06-09-2019

A global team including Czech scientists has assembled the first full genome of the common pea, shedding light on how the legume has evolved over tens of millions of years. Their work – which builds on that of the Moravian monk Gregor Mendel – is a vital part of an effort to grow high-yield, sustainable crops to feed Earth’s growing population as the climate changes.

Pea, photo: Rasbak, CC BY-SA 3.0Pea, photo: Rasbak, CC BY-SA 3.0 The Augustine monk Mendel, you may recall from high school science class, is the “father of modern genetics”. Inspired by his professors at Palacký University in Olomouc, in the mid-1850s he began tracking pea plant characteristics in the garden of Abbey of St. Thomas, in his hometown, Brno.

Mendel was hardly the first to crossbreed plants to favour desirable traits. Some 10,000 years ago, Neolithic farmers in the Fertile Crescent domesticated the common pea (Pisum sativum), and as it spread the globe over the centuries, farmers developed strains to suit their needs.

But the scientific rules of heredity – genetics – were not set out until Mendel tracked seven characteristics of pea plants over eight growing seasons, meticulously counting some 40,000 blossoms and 300,000 peas from 10,000 plants.

It was he who coined the terms “recessive” and “dominant” in reference to inherited traits, a foundation for Darwin’s theory of evolution. Now, more than 150 years after Mendel’s garden grew, the legume’s full genome – the entire collection of genetic codes determining all manner of characteristics – has been mapped.

Dr Jan Bartoš is among the Czech scientists who worked on the project, at the Olomouc laboratory of the Institute of Experimental Botany, building on Mendel’s legacy.

“It is certainly nice to participate in a project where the genome of peas, the crop that led to the birth of genetics, was actually sequenced.

“We developed the method for sorting individual chromosomes and worked on their sequencing. Then, at the end of the whole project, we helped compose the whole sequence using optical mapping technologies.”

Genomes contain highly repetitive sequences of DNA. The genome assembly of the common pea spans about 4.45 billion letters – a third more than human beings’.

It was Czech scientists at the Institute of Plant Molecular Biology in České Budějovice – using biochemical methods and computer algorithms that they developed – who identified the composition of the legume’s centromeres, which transfer genetic information via cell division.

Gregor Mendel, photo: archive of Radio PragueGregor Mendel, photo: archive of Radio Prague Mapping the pea’s full genome took six years. It has revealed how the cultivated variety and its wild cousins differ from their common ancestor of 50 million years ago.

All of which can help ensure global food security by developing higher-yield varieties that thrive under harsh conditions. Plus, consuming more legumes and less meat is healthier for people and the planet. Dr Jan Šafář, head of the Institute of Experimental Botany, explains:

“Meat leaves a huge ecological footprint, and especially young people are looking to lead healthier lifestyles and making better dietary choices for the planet.

“Peas are not only tasty; they are a significant source of protein, with twice the protein of cereals. The composition of pea protein is also much healthier than that of grains.”

Ironically, Dr Šafář notes, peas are not widely cultivated today in the land of Mendel. But the genome mapping project should lead to the development of varieties better suited to Czech farming conditions.

06-09-2019