This study, published in a Nature journal, uses DNA collected in samples from twenty-one different countries to study the characteristics of the bacterial communities which inhabit the soil. The research team, made up of thirty-six scientists from around the world, has examined over 1900 different soils, containing over 8,000 different bacterial groups. The results obtained show how some groups always appear in the soil, independently of the place on the planet where the samples were collected. However, other bacteria are more specific and can give data related with the key characteristics of soils, such as their fertility.