4000 Year old teeth provides evidence to support the "disappearing microbiome" hypothesis

 Two teeth, from the same man, were excavated from Killuragh Cave, County Limerick and studied by archaeologists from the Atlantic Technological University and University of Edinburgh. The teeth showed advanced dental decay and had a high amount of Streptococcus mutans DNA, a strain of bacteria that is linked to gum disease tooth decay. Though S. mutans is common in modern mouths, it is very rare for the strain to be seen in ancient teeth, which makes this finding in these teeth vital for creating a truer version of the lineage of mouth bacterias. More and more dental cavities have become common due to sugary foods being introduced in masses, which may explain why the presence of S. mutans is so rare in ancient teeth. Scientists also found that other streptococcal strains were missing from the teeth while other divergent bacterias common in gum disease, like Tannerella forsythia, was found.  Dr. Cassidy, an author of the study, explains, "a single lineage of T. forsythia has become dominant worldwide. this is the tell-tale sign of natural selection..." (ScienceDaily). T. forsythia being present added evidence of natural selection for this strain and answered other questions about gum disease bacteria's history. 

I think analyzing fossils, and finding answers from something thousands of years old is always worth reading about. The thought of the evolution of the microbiome of the mouth is not something usually thought about but, these findings are vital for gum disease history and human mouth health. Learning more about what sweets can do to human teeth and how tooth decay affected people from up to 4000 years ago was very interesting and thought provoking, considering the age of these teeth. It's also interesting to see how the microbiome has changed, how some strains are missing while others are that are present now, are missing then. I also thought it was important to mention how these findings were considered to support "loss in biodiversity" which supports the "disappearing microbiome hypothesis". This hypothesis proposes that "modern microbiomes are less diverse that those of our ancestors" (ScienceDaily). Overall, I thought it was an interesting read and sparked a hope that more research about the history of tooth decay and gum disease is done. 

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

https://academic.oup.com/mbe/article/41/3/msae017/7617356 

Potential Recovery of Dinosaur DNA!

 This article details an account which claims that $125 million-year-old DNA has been recovered from a dinosaur called Caudipteryx. Scientists claim that the fragments of chromatin and nuclei within the fossil could contain preserved DNA, which could then be extracted and studied. However, mass skepticism surrounds this idea. Currently, the oldest sequenced DNA belongs to a million year old woolly mammoth, and, given how long ago dinosaurs went extinct, the idea of sequencing multi-millions of years old DNA is nearly unheard of… This is due to DNA's fragility. The dinosaur DNA was allegedly extracted from fossilized femur cartilage, found in China. This fossil was exceptionally preserved, as the site it was found at is known for fossilization via fine volcanic ash- prime preservation conditions. However, the main concern surrounding this is the idea that the genetic material being found could actually be from microbes on the fossils, not the dinosaurs themselves. This is a problem that researchers commonly run into, not only with dinosaurs, but other ancient organisms as well.

Personally, I think that the concept of being able to study ancient DNA, and then further learn from it in the present day, is fantastical. However the obvious problems of being unable to differentiate between modern organisms and fossil DNA is a major setback. Additionally, due to DNA's tendency to break down over time, unfortunately, I am also a skeptic in regards to whether or not DNA was actually recovered from this dinosaur. However, if somehow we were able to develop a way to differentiate modern versus ancient DNA, I think it would be amazing to compare ancient DNA to modern DNA, and see just how similar dinosaur DNA is to that of modern organisms. 

Horseshoe crabs are really relatives of spiders, scorpions

In an article from Science Daily, scientists used genetic data analysis and concluded that horseshoe crabs belong to the arachnid family tree. Arthropods are considered to be the most successful animals on the planet and the group include insects, crustaceans, and arachnids. Although horseshoe crabs are marine animals and known to be in the arthropod family, their genomic data have repeatedly shown their relationship with arachnids like spiders, scorpions, ticks, and mites. Horseshoe crabs are the only marine animals to breathe with book gills which is similar to the book lungs spiders and scorpions in land use to survive. There are only 4 species of horseshoe crabs that are alive today. According to the fossil record, the first group appeared 450 million years ago with extinct lineages like scorpions. In order to test the complex relationship among horseshoe crab with other species, scientists from University of Wisconsin-Madison compared the genomic sequence of the three out of four of the alive horseshoe crab against the genome sequence of 50 other arthropod species. As a result of the analysis, the research revealed that horseshoe crabs nested in the arachnid family.

Some scientist might not agree with the findings of this study because of the difference in colonization of the two species of animal. Horseshoe crabs are water dwellers while the arachnids colonized land. These animals belong to a group called Chelicerata and possibly have a common ancestor. I do think that more research with major characteristics of the two species needs to be done with major in order to support the data of this study.

Possible Re-write of the Elephant Family Tree

For many years, scientists thought they had the elephant family tree mapped out. However, a recent discovery of an ancient elephant fossil forces scientists to rethink the family tree.

What we know now is that there are three species of modern elephants:
1. The Asian Elephant (Alphas maximus)
2. The African Elephant- forest dwellers (Loxodonta cyclotis)
3. The African Elephant- Savannah (Loxodonta africana)

Straight Tusked Elephant (Paleoxodon antiquus)

We also know that scientists believed the ancient predecessor, the Straight Tusked elephant (Paleoxodon antiquus) was the closest relative to the Asian elephant. But new research shows that the predecessor is actually more closely related to the African forest elephants. Even more new research of the mammoth genome reveals that mammoths and elephant species were known to interbreed in the past. This means the elephant family tree will need to be minimally altered.

What we know about the Straight Tusked elephant:
The Straight tusked elephant lived in European forests until 100,000 years ago.
Straight tusked elephants and mammoth species have interbred.
Straight tusked elephants have interbred with Asian elephants.
Straight tusked elephants represent the oldest whole genomes from a warm environment.


The greatest fascination about the elephant genome is that the Straight tusked elephant genome wasn't just sequenced, it was sequenced in such high quality, that each letter was sequenced on average
15 times, leaving many scientists in complete awe.

For more about the interbreeding of the mammoth and elephant: http://www.iflscience.com/plants-and-animals/scientists-successfully-insert-woolly-mammoth-dna-elephant-genome/