Evolution and DNA Testing
What can DNA testing tell us about evolution on earth?
DNA testing and heredity
Do you ever look at your relatives and think that you have the same eyebrows as your sister, the same face shape as your grandma or the same eye colour as your mum? Even if you don’t see it, no doubt someone outside of your family will remark upon shared similarities. You don’t need DNA testing to realise that your parents pass on a likeness to you, and that you pass on a family resemblance to your own children, and so on.
First steps
Remarkably, DNA testing reveals more than the fact that we share DNA with our immediate relatives or that DNA confirms hereditary. It has also taught us that we share DNA connecting us right back to the Earth's first living organisms. DNA testing and genetics help scientists explain how each species originated from a common ancestor.
DNA testing throws up big questions
Before you grew older and became pre-occupied with life's everyday worries, it’s likely you asked the big questions in life – where did it all begin, why do we exist, where does space end. DNA testing can assist in finding the answers. Scientists believe that around four and a half billion years ago, the Earth was inhabitable. But after the first billion years, a huge array of species roamed earth. It is thought that organic molecules formed in the atmosphere, which then organised themselves into single-celled organisms. From that came algae, crustaceans, plants, insects, fish, reptiles, birds and mammals.
Charles Darwin's theory of evolution
Darwin is famed for his evolutionary theories as detailed in 1859 in his classic book On the Origin of Species. This follows the idea that natural selection determines what adapts to survive and what doesn’t. Although DNA testing reveals our genetic make-up, and we all share DNA (we share the majority of our DNA with monkeys,) natural selection works on the principle that the animal with the best qualities will be more successful reproducing. The ones that do not perform as well will fail and eventually become extinct.
Inheritance
This theory was confirmed by a monk called Mendel who in the mid-19th century discovered we carry two genes – one is dominant, one is recessive. When we reproduce, the recessive gene is swamped in our offspring. This explains, without the need of DNA testing, why we inherit specific traits. |
