Humans may be descendants of aliens. This odd-sounding possibility stems from the discovery of chemicals that make up human deoxyribonucleic acid (DNA) in an asteroid that hit Earth billions of years ago.
This means that the seeds of life may have been planted on Earth from elsewhere in the universe, and humans could have reproduced on other planets very far away. Samples from three carbon-rich meteorites, called Murchison, Murray and Tagish Lake, were analyzed using the best of techniques.
It was Professor Yasuhiro Oba, from the Institute of Low Temperature Science at Hokkaido University, Japan, who revealed this finding. "We found a wide variety of organic materials, including nucleobases, the basic building blocks of our life," he said.
"These could have been sent to Earth via asteroids, meteorites, comets, and interplanetary dust particles four billion years ago when our planet was bombarded by debris from space."
He believes the inclusion of organic matter played an important role in the evolution of life on Earth. "This is a very exciting discovery that expands our understanding of how life began," he said.
Quoted from Reuters, scientists had previously detected three of the five chemical components needed to form DNA, the molecule that carries genetic instructions in living organisms, and RNA, a molecule that is important for controlling the actions of genes.
The researchers say they have now identified the last two components after refining the way they analyzed meteorites.
Unlike previous studies, the method used this time is more sensitive and does not use strong acids or hot liquids to extract the five components, known as nucleobases, according to Oba, the lead author of the study published in the journal Nature Communications.
Nucleobases are nitrogen-containing compounds that are important in forming the characteristic double helix structure of DNA. Confirmation of the extraterrestrial origin of a complete set of nucleobases found in DNA and RNA supports the theory that meteorites could be an important source of organic compounds necessary for the emergence of the first living organisms on Earth, according to astrobiologist and study co-author Danny Glavin of NASA's Goddard Space Flight Center. in Maryland.
Scientists have been trying to better understand the events that occur on Earth that allow various chemical compounds to gather in warm watery environments to form living microbes that can reproduce themselves.
The formation of DNA and RNA would be an important milestone as these molecules essentially contain the instructions for building and operating living organisms.
"There's still a lot to learn about the chemical steps that led to the origin of life on Earth, the first self-replicating system. This research certainly adds to the list of chemical compounds that would have been in the prebiotic soup of early Earth," said Dr. Glavin.