AP Biology class blog for discussing current research in Biology

Author: cellillymembrane

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?

How The Animals of Africa Can Help To Understand The Human Body

Scientists have been studying the microbiome of animals and humans for years. DNA analysis has proved to be a method of research that allows scientists to understand the microbiome better. Researchers at Brown University have recently added onto this knowledge by conducting a study focusing on the microbiomes, diets, and environments of animals.

The Study:

In a recent study conducted by Brown University, scientists analyzed animals’ feces collected by researchers in Kenya in order to further explore the relationship between the microbiome, environment, and diet. The had researchers from the Mpala Research Centre in Kenya collect approximately 1,000 samples of feces from 33 different herbivore species such as elephants, giraffes, and antelopes. The samples were then analyzed, specifically the DNA in the samples were analyzed, and the researchers came to three conclusions.


One, similar or closely related species showed evidence of similar microbiomes. Two, animals with different diets had different microbiomes. Three, animals experienced environmental seasonal changes also experienced seasonal changes in their microbiome. Based on these conclusions, Tyler Kartzinel, a current assistant professor at Brown University and former researcher of Princeton University, hopes to further study the degree to which seasonal changes affect certain animals’ microbiomes and answer questions such as whether or not seasonal sensitivity in the microbiome is a sign of good health.

Why Is This Important?

The findings of this study have opened up a door to more question to be answered and research to be done. Future research will focus on the health of wild animals whose microbiomes change significantly based on their seasonal sensitivity. This is only the beginning of a series of studies that could continue on to figuring out how we can manage the human microbiome in order to improve overall human health using DNA and genetic findings. I think it is very interesting how some samples of animal feces in Kenya could be the start of a series of studies used to improve the health of humans. What do you think?

Zebra Finches Help Us Understand Speech Development

It has been known for decades that humans learn by imitating the actions and overall behaviors of their parents. In terms of learning speech, it is the memorization and imitation of syllables and sounds that allow humans to develop speaking skills over time. Still, there are some uncertainties as to exactly how the brain stores the memories needed to speak and whether or not humans can interfere with or alter the process. A group of scientists worked to answer these questions.

The Study

A recent study conducted by UT Southwestern Medical Center used zebra finches to test whether or not the memories needed to replicate speaking patterns could be formed without the use of another bird to imitate the sounds from. The answer was found through optogenetics, a process in which light is used to control areas of the brain. In the experiment, Dr. Todd Roberts, a neuroscientist with UT Southwestern’s O’Donnell Brain Institute, essentially encoded memories into the zebra finches’ brains by controlling the interactions of different regions of the brain using optogenetics. In this process, light was used to activate the neurons of a desired region of the zebra finch’s brain. The duration of time the light was shown of certain neurons corresponded to the duration fo time a syllable of a song was sung by the bird. This action-reaction process was a new “memory”. The zebra finch would now use this event as a memory to try and replicate again to learn full songs.

Dr. Roberts stated, “We’re not teaching the bird everything it needs to know — just the duration of syllables in its song.”

This discovery gives pathways to understanding different speech related circuits in the brain. Just this little piece shows that it is possible for the memories we use to learn how to speak to be generated by an artificial source, and not a living mentor.

Why is this Important?

Zebra finches vocal development is very similar to that of a humans; they hear a note sung by their father, memorize it, and repeat it. The discoveries found in this study are “providing strong clues of where to look for more insight on neurodevelopmental disorders,” says Dr. Roberts. This study could provide evidence and guidance to helping those with autism, a condition that often effects language and speech development in an individual, as well as any other neurological disorder that affects the brain. Technology and research like this can help so many people struggling with speech disorders. I believe it is important to take advantage of the resources we have today and use them to help people who need it. Do you agree? Leave a comment below!

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