Just think about it. Your very own identity is decided by combinations of 4 letters of DNA (A, T, G and C).
There’s so much DNA in your body that it can stretch all the way to the moon.
All living things have DNA. Like an instruction manual, DNA instructs your body how to build itself and behave.
It operates by building protein molecules. Ultimately, it’s protein molecules that determine who you are. For example, it gives you physical characteristics and personality traits.
The RNA chicken and the DNA egg
A quick recap on the differences between RNA and DNA:
Both DNA and RNA carry genetic information. But DNA cannot leave the nucleus. Since RNA can leave the nucleus, it copies the information found in DNA.
When it leaves the nucleus, it finds a ribosome to be able to make proteins. Ultimately, it’s protein molecules that decide who you are.
So like the chicken and the egg, which came first? Scientists don’t have a definite answer.
Most biologists believe RNA preceded DNA because its structure is simpler. RNA can grasp onto other molecules and boost the speed of chemical reactions.
This is why biologists believed that RNA made the first DNA. Because DNA can store information better than RNA, RNA evolved into a DNA world.
RNA and DNA are the building blocks for life
The truth is:
We don’t know the origin of DNA. Scientists haven’t been able to replicate the spark that built the chemical building blocks for life.
Scientists once believed the excessive heat during the late heavy bombardment stage sterilized Earth’s surface. In other words, microbes could not survive the harsh conditions on Earth at the time.
But the impacts during this violent time in Earth’s history could have created subsurface and underwater environments. Within these hydrothermal vent, any microbial life on Earth could find refuge as its own habitat.
Scientists are trying to recreate these conditions and collisions that took place to reconstruct the origins of life. This is where organic compounds and amino acids had the right conditions to synthesize from inorganic matter.
Around 4 billion years ago, there’s strong evidence that all living things originated from a common ancestor called the last universal common ancestor (LUCA). Eventually, eukaryotes formed from endosymbiosis. Finally, diverse life truly emerged during the Cambrian explosion.