Find Out Why All Dentists are Having Trouble Falling Asleep

Teeth are well known to paleontologist for their prevalence and insight into the fossil record. Recently, geneticists are starting to starting to take notice as well.

Researchers at Trinity College Dublin have found two human teeth dating back some 4,000 years ago, and found that the microbiome of the mouth they came from was also remarkabley preserved. This allowed them to study the bacteria present and compare it to typical microbiomes of human oral cavities today. Not a huge surprise, but it was very different. The researchers were able to identify what bacteria was present from the perserved DNA profiles on the teeth.

The insights it gave them was that typical microbiomes in mouths 4,000 years ago may have been much more diverse than today. Although the teeth studied were over colonized by one bacteria S. mutans, demonstrating a pre-disease state, the fact that there was more biodiversity on the ancient teeth than our own is cause for concern. Like our guts, bacterial diversity is usually better and prevents overgrowth of disease causing strains. This pointed them to our changing diet, and the growing abundance of processed sugary foods some of us enjoy eating day to day. It is interesting to see Genetics having utility in archeology. Perhaps rock-lovers may soon be recruiting more DNA lovers for their specimen studies.

Posted by Michael Breslin

https://phys.org/news/2024-03-genetic-secrets-year-teeth-illuminate.html

https://www.sciencedaily.com/releases/2024/03/240327124735.htm

The Oldest Animal DNA Ever Recovered Reveals Mammoths’ Evolution

 

Genetic material from ancient mammoth molars becomes the oldest data ever recorded from an animal. The mammoth DNA was extracted from three molars unearthed in the 1970s from permafrost in northeast Siberia. The cold permafrost helps to protect genetic information from rapidly falling apart. Theoretical studies had suggested that researchers could perhaps recover DNA that is more than 1 million years old.  This beats the previous record set by 700,000-year-old DNA from a frozen, fossilized horse. The oldest two specimens of mammoth, dubbed Krestovka and Adycha, lived around 1.2 million to 1 million years ago. Genetic analyses of ancient DNA recovered from these specimens suggest that Krestovka and Adycha belonged to two different mammoth species. Researchers had previously thought that only one type of mammoth, called the steppe mammoth, lived in Siberia 1 million years ago. While Adycha was part of the steppe mammoth lineage that eventually gave rise to woolly mammoths, the Krestovka mammoth may have diverged from its relatives more than 2 million years ago. This could represent an unknown line of mammoths, which could have mixed with woolly mammoths and given rise to the Columbian mammoth. This mammoth roamed North America at least 420,000 years ago. The study adds to the amount of mammoth genetic material researchers have decoded and expands the geographical range where such mammoth samples have come from. Analyzing the genetics of many mammoths from varied locations is how you get to learn their biology and how diverse they were. It is very interesting that they were able to discover important discoveries like this.

links

1.https://www.sciencenews.org/article/oldest-animal-dna-ever-recovered-mammoth-evolution

2. https://earthsky.org/earth/worlds-oldest-dna-mammoth-evolution-video

DNA from 5,700-year-old ‘gum’ shows what one ancient woman may have looked like

 

According to ScienceNews, fossilized bones and teeth are not the only source of ancient human DNA. In an article by Sofie Bates, a 5,700-year-old gum was discovered. Birch pitch also known as gum could hold enough DNA to piece together the genetic instruction books. The gum was discovered in Denmark and a team was able to obtain the genome of an ancient women. They were able to figure out that she probably had blue eyes, dark skin, and dark hair. Birch pitch was heated and made pliable; birch is also resistant to bacteria and viruses which is why the DNA was protected from decay. "The team also recovered DNA from microbes that may have lived in the woman’s mouth, including from older versions of Epstein-Barr virus, which causes mononucleosis, and bacteria that can cause pneumonia or gum disease." I think this article was interesting because who would of thought that a piece of 'gum' could have described the appearance of an ancient woman. I've always heard about fossils, but this is the first time I'm coming across a 5,700-year-old gum that still contained old DNA. 

Did The Ancient Egyptians Farm Ibises?

Ibises are a bird native to Africa with a long scythe-like beak that hunt by wading through rivers. They are a sacred animal to the ancient Egyptians. Their god of writing and wisdom, Thoth, is often depicted with the head of an ibis. As an offering, the Egyptians would mummify ibises and place them in catacombs.


Scientists have discovered rooms filled floor to ceiling with these sacrifices. This raises an interesting question. Where did these birds come from? Ibises have not been native to Egypt in hundreds of years. It is unknown if they migrate in large enough flocks with high enough frequency to provide the quantity of birds required for these uncovered offerings. A theory offered instead is that they were farmed by Egyptians.

The mummification process is fantastic at preserving DNA. Scientists were able to extract mitochondrial DNA from several birds. Due to controlled breeding, you would expect to see lower levels are variance between domesticated individuals. Instead, scientists found the same levels as measured in modern day ibis wild populations. While this is not enough evidence to rule out the possibility of Egyptian farms, it suggests there might be more to the story than we currently know. I thought this was an interesting application of mitochondrial DNA. Since the mitochondrial DNA is passed down from the mother, I wonder if its possible to trace the lineage of a modern ibis to one of these mummified birds.

Links:
https://search.proquest.com/nytimes/docview/2314696925/C49933956F5741C4PQ/19?accountid=29054
https://www.smithsonianmag.com/smart-news/dna-suggests-ancient-egypts-millions-ibis-mummies-were-wild-caught-birds-180973556/ 

Dental plaque leads to news about Neanderthal diet

Research done by  Laura Weyrich, a microbiologist at the University of Adelaide in Australia, has shown that plaque found in fossilized teeth proves that Neanderthal diets were a wide range of things. DNA was recovered from calcified plaque on teeth from four Neanderthal individuals. Two groups were found, one from the grasslands and one in the forests. The DNA from the individuals around the grasslands proved to eat woolly rhinoceros and wild sheep and the DNA from forests showed to eat moss, mushrooms and pine nuts. This shows that Neanderthals were neither vegetarian or herbivores. Also found in the DNA were materials from trees that act as aspirin. Any information found in fossils is truly amazing. To further our knowledge on the cavemen, helps us understand evolution and how we are today. This article shows that the Neanderthals were very smart, and knew about medicine way before we thought they did. This is a major break through for us. 



Article: https://www.sciencenews.org/blog/science-ticker/ancient-dental-plaque-tells-tales-neandertal-diet-and-disease
Related article: http://www.pnas.org/content/108/2/486.full.pdf

Asians and Europeans; Lactose-Intolerant 5,000 Years Ago

     Studying ancient DNA has always been a big part of genetics as it gives insight into the past history of humans. What was generally already found is that around 5,000 years ago, Europeans and Asians are generally light-skinned and - surprisingly - lactose intolerant. During the Bronze Age, which ranged from the years of 3,000 - 5,000 years ago, was a time of mass human migrations throughout the region of Europe and Asia. Because of these large migrations, the present-day demographic structure has been developed. 

     Researchers have sequenced genomes from 101 unearthed ancient humans from Europe and Asia. Although DNA sequences have previously been studied using ancient DNA, the new technology that is available makes for clearer data. It has recently been discovered by Morten Allentoft of the University of Copenhagen’s Natural History Museum and his colleagues that light-skinned Europeans were present at a high frequency already in the Bronze Age, thus implying that light-skinnedness was first developed previous to 5,000 years ago. Another conclusion from their data tells that during the Mesolithic hunter-gatherer age, the presence of blue eyes was already established. 

     These data are set to answer the question, could there be a greater distribution of Neanderthal DNA in the genomes of Europeans and Asians? This is still unclear, however the findings suggests that these humans were settled into Europe and Asia before the Bronze Age.

     Something also interesting about the data is that 5,000 years ago, humans had not evolved the enzyme to break down lactose - the sugar found in milk. In an evolutionary perspective, this makes sense because ancient humans and - in fact, mammals in general - do not need to drink milk to survive after infancy, thus the lactose intolerance. When humans began to produce the enzyme to break down that indicated the start of domestication of animals which did not occur much before 5,000 years ago thanks to the data. 

     I personally think that this article is interesting because there are people who today are still lactose intolerant. The article tries to explain this as their ancestors did not drink much milk, thus never needing the enzyme to break down lactose. It is amazing how using the preserved DNA from bones that have been under the earth for so long can lead to vast discoveries like this. This discovery tells a lot about the time line of when humans became what we are today.

Original Article

More about the Bronze Age