BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: new discovery

How Do Fish Get Their Shape?

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On January 21, 2020

In Student Post

Researchers in The National University of Singapore discovered how fish create their chevron pattern. 

The chevron shape itself and the shape’s function in locomotion have been used to infer the evolutionary relationships among chordates. However, the development of the chevron has not been fully researched until now. 

The research team mainly focused on the myotome, a group of muscles forming the spinal nerve root in fish. These muscles make up most of the fish body and help them become more efficient with side-to-side swimming motion. The myotome creates the “V”  pattern, or chevron pattern, in fish, which helps them increase their swimming efficiency. 

One factor that determines the shape of fish is the friction and stress of their muscles. When the myotome first develops in fish, it forms a cuboidal shape before it deforms into a V shape. Dr. Sham Tlili and Professor Timothy Saunders, head researchers of the project, used zebrafish embryos to examine the deformation process of the myotome from a cuboidal to V shape. Developing myotomes in embryos are connected to embryonic tissues, such as the notochord, and each connection has a varying level of friction. The researchers discovered that the sides of the myotome experience more friction than its central side. 

Picture of chevron pattern on fish

The team also revealed that cells of growing myotome become longer as muscle fibers are formed. This elongation incites a force, which is what creates the “V” pattern on fish. 

Professor Peter Wainwright, a biological professor in UC Davis, also determined that patterns of fish could be split into two groups: midwater fish and deep water fish. “As you get down into the water column, when you have more substrate and more complexity in the habitat, you definitely find more variation and elongation,” said Susman, one of Wainwright’s students. 

Professor Saunders, when asked about the results of the experiment, states that  “This work reveals how a carefully balanced interplay between cell morphology and mechanical interactions can drive the emergence of complex shapes during development. We are excited to see if the principles we have revealed are also acting in the shaping of other organs.”

 

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

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On January 21, 2020

In Student Post

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?

“Look! Up In The Sky! It’s a Bird! It’s a Plane! It’s…. A Blue-Throated Hillstar!

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On October 14, 2018

In Student Post

A decade ago, most scientists and bird-watchers believed that there were between 9,000 and 10,000 species of birds on the planet. A new study in 2016, however, led by the American Museum of Natural History, doubled that estimate, suggesting that there are 18,000 bird species in the world. One big step in the discovery of these unknown bird species was announced just several weeks ago, with the finding of a new species of hummingbird in Ecuador. Named Oreotrochilus cyanolaemus, or blue-throated hillstar, the species was discovered in the Andes by a multinational team of ornithologists from Ecuador, Venezuela, Denmark and Sweden. Dr. Francisco Sornoza-Molina of the Instituto Nacional de Biodiversida in Quito, Ecuador, and his colleagues first photographed the hillstar during fieldwork in the Ecuadorian highlands back in April of 2017; they would return later that spring to verify the finding.

File:Lampornis clemenciae.jpg

Hummingbird that resembles the blue-throated hillstar | Taken by Sheri L. Williamson

The blue-throated hillstar is approximately 13 centimeters in length and has a slightly curved beak, which it uses to reach the flowers of the chuquiragua, an Ecuadorian plant known as the “flower of the Andes” or “flower of true love” that is used to brew tea. It has a rich, deep-blue neck and greenish-blue head and body feathers.

Ecuador is rich in biodiversity, containing 132 hummingbird species out of the more than 300 in the world, but that doesn’t make the discovery any less surprising. Hummingbird expert and researcher at the University of New Mexico, Dr. Christopher Witt,  commented, “The hillstar hummingbirds occur in the most rugged, isolated, and inaccessible parts of the Andes, where they roost in caves, forage on the ground, and spend half their lives in hypothermic torpor, so the discovery of a new species in this group is incredibly exciting.” With estimates on the number of individuals of blue-throated hillstars varying between 250 and 750, ornithologists agree that the species is in danger of extinction, with its high-altitude habitat between the provinces of Loja and El Oro near the Pacific Ocean threatened by gold-mining, fire, and grazing. Commenting on the life-threatening conditions facing the blue-throated hillstar, Dr. Sornoza-Molina of the research team said, “Complete support from national and international conservation agencies is needed in order to save this species. The action plan for the conservation of this bird is creating a network of protected areas along its geographic range.”

Biomedical Engineers paving the way for Immunology

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On April 13, 2016

In Student Post

For many years Biomedical Engineers have been attempting to find ways to make precise, efficient, and deliberate changes to the genetic material of living cells. Developments in this field can, not only help to eradicate many genetic diseases but it can also ensure what many scientists call “adaptive immunity”. With their newfound CRISPR – Cas9 technology, they may have found a solution to the problem that has been giving them so much grief

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Adaptive Immunity occurs when a foreign body is recognized specifically for what it is and how it can harm the body. The other form of immune response is the innate response, in which there is a foreign body identified and the immune system sends any type of immune-response cell to general area to kill it. However, in adaptive immunity the body can individually recognize the problem and send exactly what needs to be sent, a much more efficient process.

Moreover, scientists hope that a cell’s ability to perform adaptive immunity will help contribute to eliminating harmful genetic mutations. Researchers hypothesize that, with this newfound technology, cells will be able to identify and respond to invading genetic material from a bacteriophage or invader of any sort. (quite possibly eradicating HIV and all other viruses from the Earth).

The science behind this new genetic-police force is as confusing as it is difficult to say… CRISPR…Cas9… what does any of that even mean?

CRISPR stands for Clustered Regulatory Interspaced Short Palindromic Repeats

Cas9 comes from the name of the protein-9 nuclease that scientists first found in Strep (Streptococcus Pyogenes) cells back in 2007 which help the bacteria participate in adaptive immunity.

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All in all, its some pretty crazy and extremely complex stuff.

If you do so please, I suggest doing some of your own research on this topic if you have any questions. The opportunities afforded by this breakthrough are endless.

ORIGINAL Article: https://www.neb.com/tools-and-resources/feature-articles/crispr-cas9-and-targeted-genome-editing-a-new-era-in-molecular-biology

New Species Related to Humans Uncovered

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On October 14, 2015

In Student Post

On September 10th, 2015, the University of Witwatersrand, the National Geographic Society, the Department of Science and the National Research Foundation of South Africa announced the discovery of a new species of human relative, Homo naledi. With more than 1,500 numbered fossil elements, this discovery is the largest fossil hominin find ever made on the continent of Africa. Not only does this finding shed light on the origins and diversity of our genus, but it appears that this new species intentionally deposited the bodies of its dead in a remote cave, an action previously conceived limited to humans.

Homo_naledi_hand

https://commons.wikimedia.org/wiki/File:Homo_naledi_hand.jpg

The species was initially discovered in 2013 in a cave known as Rising Star in the Cradle of Humankind World Heritage Site, some 50 km northwest of Johannesburg, South Africa. The fossils were laid in a chamber about 90 meters from the cave’s entrance, which was accessible only through a narrow chute which required a special team of very skinny individuals to retrieve them. Up and till now the team has recovered parts of at least 15 individuals of the same species. Lee Berger, research professor at Wits University and leader of the expeditions that recovered the fossils said, “With almost every bone in the body represented multiple times, Homo naledi is already practically the best-known fossil member of our lineage.”

Homo naledi has surprisingly human-like features, enough to place it in the genus Homo. It has a tiny brain, about the size of an orange (about 500 cubic centimeters), on top of a very slender body. The research shows that on average H. naledi stood approximately 1.5 meters (about 5 feet) tall and weighed about 45 kilograms (almost 100 pounds). Homo naledi‘s teeth are described as similar to those of the earliest-known members of our genus, such as Homo habilis, as are most features of the skull. The shoulders, however, are more similar to those of apes. The hands also suggest tool-using capabilities. It has extremely curved fingers, more curved than almost any other species of early hominin, which clearly demonstrates possible climbing capabilities.

The most remarkable part of the find is that it has led the researchers to conclude that this primitive-looking hominin may have practiced a form of behavior previously thought to be unique to humanism, intentional body disposal. The space in which the fossils were discovered was so remote that out of more than 1,550 fossil elements recovered, only about a dozen are not hominin, and the few that were not are isolated mouse and bird remains, meaning that the chamber attracted few accidental visitors.

The researchers explored every alternative scenario, including mass death, an unknown carnivore, water transport from another location, or accidental death in a death trap. After examining every other option, they were left to accept intentional body disposal by Homo naledi as the most plausible scenario.

There is still much to be discovered in the Rising Star cave. “This chamber has not given up all of its secrets.” There are potentially hundreds if not thousands of remains of Homo naledi still down there waiting to get uncovered. 

Original Article:  http://www.biologynews.net/archives/2015/09/10/new_species_of_human_relative_discovered_in_sa_cave.html

For more information, check out:  http://news.nationalgeographic.com/2015/09/150910-human-evolution-change/

Hearing Loss Clue Uncovered

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On September 29, 2013

In Student Post

In the United States, approximately forty-eight million (twenty percent) of men and women suffer some degree of hearing loss, as it is the third most common physical condition after arthritis and heart disease. While it is most often associated with the population sixty-five and
older, hearing loss effects all ages, as thirty school children per out one-thousand are afflicted in some varying degree. An individual is able to hear sound involving the ear’s main structures. In age-related hearing loss, one or more of these structures is damaged: the external ear canal, the middle ear, and the inner ear. External ear canal impairment is related exclusively to conducive hearing loss. The middle ear, which is separated from the ear canal by the eardrum may be caused by sensorineural hearing loss. Lastly, the inner ear, which contains the cochlea, the main sensory organ of hearing. When the vibrations from the middle ear enter the cochlea it causes the fluid to move and the sensory hair cells pick up this movement. In response to the movement of the fluid the hair cells send an electrical signal up the auditory nerve to the brain where it’s recognized as sound.

 

Now, how do these different internal departments of the human ear gradually induce hearing loss? While we get older, some may develop presbycusis, which causes the tiny hair-like cells in the cochlea to deteriorate over time. Clarity of sound decreases, as the hairs are unable to vibrate as effectively in response to sound. Recently, otolaryngologists have discovered new evidence that human hearing loss relates to a certain genetic mutations. A study at the University of Melbourne revealed “a novel genetic mutation was first identified in 2010 as causing hearing loss in humans… now discovered that this mutation induces malfunction of an inhibitor of an enzyme commonly found in our body that destroys proteins – known scientifically as SERPINB6. Individuals who lacked both copies of this “good gene” were shown to have lost their hearing by twenty years of age.

 

Although this discovery is changing the way scientists previously viewed hearing loss, the answer to why this mutation, SERPINB6, is a catalysts for such loss, is inconclusive. However, this mutative gene has created a revelation for many: it is now not unusual to show gradual signs of hearing loss under the age of sixty years.

 

To better understand the effects of the mutant gene, mice were used in order to imitate the condition from youth to adulthood. At only three weeks of age, mice with SERPINB6 had begun to lose hearing – three weeks is equivalent to pubescent or teenage years in humans. And as we could have predicted, the mice continued to show a decrease in hearing ability, much the same as humans. Researchers examined the mice’s inner ear, which revealed the cells responsible for interpreting sound (sensory hair cells) had died.

 

Fortunately, this new discovery of a mutant gene in human sensory cells has created new attention to better understand the case of those who are effected by the condition. 

 

 

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