BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: Ancient DNA

Shocking Connection Between Ancient Neanderthals and COVID-19

As stated in an article that details the shocking discoveries of an investigation led by Professors Svante Pääbo and Hugo Zeberg, genetic material from our neanderthal ancestors can be linked to the development of severe COVID-19. COVID-19, as I am sure you are all aware, is the disease ravaging the world and is caused by the newly

discovered coronavirus. While most people only have mild reactions to the disease and recover relatively easily, some people with underlying conditions may have a severe reaction to the disease and require hospitalization. However, this new study indicates that certain people may be genetically predisposed to a severe COVID-19 reaction, and it all links back to our 60,000-year-old Neanderthal ancestors.

The study that discovered this connection analyzed the genetic material of 3,000 patients who had both severe and mild COVID-19. The study identified a section of the chromosome that contained the genetic material responsible for the severe COVID-19. Chromosomes are tiny structures located in the nucleus of cells and these structures hold the genetic material that determines virtually everything about the cell. This genetic material is made up of nucleic acids that — when combined into a double-strand helix by covalent bonds between the phosphate, sugar, and base groups– create DNA. The order of the bases in the chain determines the amino acid sequence. We inherit our genetic material from our parents, and chromosomes are present in pairs, with one part of the pair inherited from each parent. This means that you hold genetic information from your earliest ancestors, which could potentially include Neanderthals. Neanderthals were archaic humanoids that were eventually assimilated into the homo sapien species.  However, cross-breeding was required to absorb the Neanderthals into our species, which means that most of the people alive today have a percentage of Neanderthal DNA. If a person holds one of the thirteen variants that are present in Neanderthal DNA, they are far more likely to have severe COVID-19.

Professors Pääbo and Zeberg proved this to be true by discovering that the Neanderthal variants distinctly matched the variants associated with severe COVID-19. However, they discovered that the genetic material only originated from Neanderthals located in southern Europe. Therefore, they concluded that when the Neanderthals of southern Europe merged with present-day people 60,000 years ago, they introduced the DNA region responsible for severe cases of COVID-19. Additionally, the people who possess these Neanderthal variants today are three times more likely to have severe COVID-19. The fact that I found the most interesting is how dramatically the presence of the variants vary in different parts of the world. For example, in South Asia, 50% of the population holds the variants, but in East Asia, almost nobody has them. I also think that it is rather tragic how genetic material that has not had any effect on the world for 60,000 years is just now becoming active. What do you think about this discovery? Why do you believe Neanderthal DNA is causing these extreme cases?

 

How Old “Chewing Gum” Allows Us To See Into The Past

In a recent study conducted by the University of Copenhagen, scientists have discovered a complete human genome extracted from a sample of old birch pitch “chewing gum”.

 

While excavating in Lolland, and island in Denmark, archeologists found a sample of 5,700 thousand year old birch pitch sealed in mud. Since the sample was sealed in mud, it was preserved very well. The birch pitch was found in a place called Syltholm, a site where many past archaeological finds have been made.

 

Why is this Discovery Important?

This is the first time a complete ancient genome has been extracted from something other than a bone sample. Samples of oral DNA as well as other human pathogens were found which are very important finds due to the fact that there are no other human remains left from that time period. From the initial birch pitch sample, scientists could figure out that the person who chewed the birch pitch was a female who most likely had dark hair, dark skin, blue eyes, and was genetically related to hunter-gatherers.

Scientists also made bacterial discoveries. Bacteria that come from oral microbiomes were found which allows us to also study the diet and microbiomes of  the people living 5,700 years ago. Scientist Hannes Schroeder says that studying these DNA samples will help us understand ancient microbiomes as well as the evolution of human pathogens.

I think it is interesting that so much information could be uncovered from a sample of ancient tree bark tar. What do you think?

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