Scientists reveal how DNA developed on earth, thus sowing seeds of life

A previous study report had suggested that an asteroid might have sowed seeds of life on earth

A new study conducted by researchers at the University of Washington has suggested that earliest signs of life may have evolved in lakes that contain high amounts of phosphorus due to the amount of carbon present in it. Scientists who took part in this study made this conclusion after examining water taken from carbon-rich lakes that includes Lake Mono in California, and Lonar Lake in India.

Phosphorus: The backbone of DNA and RNA

Phosphorus is considered one of the inevitable six chemical elements required for life on the earth. Even though phosphorus is a very scarce mineral, on earth, it is taken as the backbone of DNA and RNA molecules.

Mono Lake
Eastern California’s Mono Lake has no outflow, allowing salts to build up over time. The high salts in this carbonate-rich lake can grow into pillars Matthew Dillon/Flickr

Scientists believe that high levels of phosphorus in carbon-rich lakes allowed phosphate molecules to remain unbound, and thus chemical reactions will happen, resulting in the formation of DNA and RNA strands.

Dry environments

During the study, researchers mainly focused on lakes in dry environments. It should be noted that these lakes have a very high evaporation rate, which will finally result in salty and alkaline solutions in the water body. These lakes, also known as alkaline lakes are present in all the continents on earth.

Researchers, during the study, noted that high concentrations of phosphorus in these lakes indicate the presence of a natural phenomenon in these lakes which results in the accumulation of minerals. In waters rich with carbonates, the carbonates outcompete phosphates to bind with calcium, and this phenomenon will leave some phosphorus unattached. The research team also noted that the phosphorus levels in these lakes used to climb up during dry seasons.

Solves phosphate problem

"It's a straightforward idea, which is its appeal. It solves the phosphate problem in an elegant and plausible way," said Jonathan Toner, a research assistant professor at the University of Washington, and the first author of the study, in a recent statement.

Scientists believe that high levels of phosphate could have triggered reactions that helped to build blocks of DNA, RNA, proteins, and fat.

"The early Earth was a volcanically active place, so you would have had lots of fresh volcanic rock reacting with carbon dioxide and supplying carbonate and phosphorus to lakes. The early Earth could have hosted many carbonate-rich lakes, which would have had high enough phosphorus concentrations to get life started," added Toner.

Asteroid sowed seeds of life on earth

A few months back, another study led by Japanese and international researchers including scientists at NASA suggested that the early seeds of life on earth might have sowed by an asteroid.

Researchers who took part in this study made this assumption after discovering a sugar molecule named ribose in two meteorites. It should be noted that ribose is a vital ingredient of RNA, and it acts as a messenger molecule that delivers data from amino acids to genes.