Every human being has at least once wondered how humans must have formed on Earth. Or what created us and when. Answers and theories have brought endless possibilities. Now, scientists have researched and have acquired answers. However, did anyone ever think that human life had been formed by the DNA or deoxyribonucleic acid which was found ages ago in special types of rocks? These are the rocks which are present in outer space.
Meteorites are fragments of spatial matter that fall on the surface of Earth. Whereas, DNA can define one’s life completely. It contains the genetic information of all organisms. According to a new study which was released in the magazine Nature Communications, the meteorites could have brought DNA to Earth.
This new study stated that the researchers found nucleobases in the meteorites. Nucleobases are nitrogenous bases namely Adenine(A), Guanine (G), Cytosine (C), Thymine (T) and Uracil (U). Scientists wonder whether these meteorites helped deliver these compounds to Earth.
Until now, scientists had only discovered A, G and U components. Yasuhiro Oba, an associate professor at the Hokkaido university and the first author of this study, along with his colleagues he researched about the three meteorites. They analysed the samples of the three carbonaceous meteorites found in Murchison, Murray and Tagish lake. The scientists found that these meteorites had T, C compounds at levels up to a few parts per billion.
The meteorite not only carried the nucleobases but also carried various other compounds within it. This resulted in the meteorites’ ability to carry such complex compounds.
During the formation of Earth, many common elements and compounds with low boiling points, known as volatiles would not have been present. Researchers believe that many of these compounds such as water were delivered after the meteorites, which may have also delivered organic molecules.
According to National Aeronautics and Space Administration (NASA), in their previous work, Oba and his colleagues had detected an elusive molecule called hexamethylenetetramine (HMT), which is thought to be an important precursor to organic molecules in the space rocks. In their new study, these researchers applied a technique called high-performance liquid chromatography. This technique helped them separate the pressurised water content from the meteorites into their component parts. Their team was thus able to extract the nucleobases. They even used a technique called mass spectrometry to study the parts in detail.
The result of their experiment was that the meteorites carried adenine and guanine compounds. The murchison meteorite also carried uracil and others at least carried one uracil isomer. Isomers are fundamentally a compound that contains the same number and types of atoms. The Murchison and Tagish lake meteorites contained thymine. Murray contained thymine isomers. This way all meteorites contained cytosine along with various isomers of other compounds.
To check that the nucleobases were extraterrestrial in origin rather than the result of Earthly combination, the team also performed blank experiments without any meteorites. Later the team worked on the soil samples found near the landing place of the meteorite. They analysed the soil and found that the nucleobases were present there too. They found that the concentration of the nucleobases in the soil were completely different from that found in the meteorites.
By comparing the diversity of nucleobases found in the meteorite against that found in soil, they therefore concluded by saying that the compounds in the space rock were formed in space itself. Moreover, they accepted that the nucleobases contributed to the emergence of genetic properties for the earliest life on Earth.
Bibliography:
Lanese, Nicoletta. ”Meteorites may have brought DNA to Earth!” Live Science. 28 Apr, 2022. Web. 21 Jul,2022 .<www.livescience.com>
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