BioQuakes

AP Biology class blog for discussing current research in Biology

Author: chloroplash

The Genetic Secrets in Monkey Poop!

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On April 28, 2018

In Student Post

 

We’ve learned that two distinct species cannot produce viable hybrid offspring, BUT…

A researcher from Florida Atlantic University has documented that two genetically distinct species of guenon monkeys in Gombe National Park in Tanzania, Africa, have been successfully mating and producing hybrid offspring for hundreds or thousands of years! How did she learn this? From their poop!

Earlier Knowledge: Previous studies showed that guenon monkeys’ widely varying physical traits keep them from interbreeding because of mate choice. In other words, a male monkey won’t be attracted  to/mate with a female unless her face matches his. Therefore, blue monkeys and red-tailed monkeys (two different species) wouldn’t be expected to mate. The two species currently live in close proximity to each other in narrow riverine forests along Lake Tanganyika in Gombe National Park, and Kate Detwiler has been studying them for years.

 

Red-Tailed Monkey https://www.flickr.com/photos/derekbruff/13353495075

Blue Monkey https://commons.wikimedia.org/wiki/File:Blue_monkey_(Cercopithecus_mitis_stuhlmanni)_pair.jpg

 

 

 

 

 

 

The Breakthrough: Kate Detwiler, author and an assistant professor in the Department of Anthropology in FAU’s Dorothy F. Schmidt College of Arts and Letters, challenges this claim that red-tailed and blue monkeys don’t mate. She studies the extent and pattern of gene flow from “red tailed” (Cercopithecus ascanius) monkeys to “blue” monkeys (Cercopithecus mitis) due to hybridization. Detwiler observes and studies the two monkey species in Gombe National Park, and recognizes hybrids by combined markings of the two parent species. She estimates 15% of the population are hybrids!

The Evidence: Detwiler uses mitochondrion DNA extracted from the monkey species to show movement of genetic material from one guenon species to another. More specifically, she examined fecal samples and found that all of the monkeys (hybrids, blues, and red-tails) have red-tailed mitochondrial DNA traced back to female red-tailed monkeys. Using mitochondrial DNA was the best option because it is more abundant than nuclear DNA and only comes from the mother. In her study, her control group was a group of blue monkeys outside the park; when she extracted DNA from these monkeys, she found that they only had blue monkey DNA. Upon studying the hybrid monkeys, Detwiler found no consequences of cross breeding.

Detwiler’s Theory: The key finding made from Kate Detwiler’s study is that blue monkeys in Gombe National Park emerged out of the hybrid population. She speculates that red-tailed monkeys got to Gombe Natoinal Park first and thrived. Male blue monkeys had to leave their original homes outside the park and then mated with red-tailed females. How was the hybrid population sustained? Detwiler believes that the monkeys have learned socially that if you grow up in a hybrid group it is okay to mate with any other monkey.

So What? “The Gombe hybrid population is extremely valuable because it can be used as a model system to better understand what hybridization looks like and how genetic material moves between species,” said Detwiler. This is especially important because hybridization often occurs in response to environmental changes, and climate change is happening now! Who knows what hybrids we will see in the future? Check out the full article here to read more about this fascinating study!

 

 

 

 

Could CRISPR Cure Duchenne Muscular Dystrophy?

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On March 7, 2018

In Student Post

What is Duchenne Muscular Dystrophy?

https://www.flickr.com/photos/150276478@N03/34406844136

Duchenne muscular dystrophy, DMD, is an X-linked recessive disease caused by defects in the gene that makes the dystrophin protein. This particular gene is made of 79 exons, and the defects can occur on any of them. These defects lead to degeneration of skeletal and heart muscle, forcing patients to rely and wheelchairs and respirators. Without a cure, most people with the disease die by the age of 30. So, the question becomes, how can we find a cure?

What is Precision Editing?

http://www.njsta.org/news/crispr-in-the-classroom-by-simon-levien

CRISPR technology has advanced tremendously in the past several years, with each study building off the last. CRISPR technology has the capability to cut out segments of DNA, but with the risk of cutting out too much or the wrong parts. Thus, it is crucial that the cutting be as precise as possible. The CRISPR-Cas9 gene-editing tool, uses an RNA strand to guide the Cas9 enzyme along the DNA strand, skipping over important “healthy” DNA and leading the enzyme to cut a specific portion of DNA.

 How do DMD and Precision Editing Connect?

Dr. Olsen is Co-Director of the Wellstone Muscular Dystrophy Cooperative Research Center, a lab in which a team has been working to apply precision editing to DMD. The method uses one single cut of DNA along strategic points and is less intrusive than other methods. Scientists have developed guide RNAs with the purpose of finding mutation “hotspots” along the dystrophin gene. The RNA strand guides the Cas9 enzyme to 12 regions where most DMD mutations have been found. According to the article, “the new strategy can potentially correct a majority of the 3,000 types of mutations that cause DMD.” Wow! In a recent study using this method, these RNAs helped rescue cardiac function to near-normal levels in human heart muscle tissue.

Why is it Important?  

The new study demonstrates eliminating abnormal splice sites in human DNA can correct a wide range of mutation. In the case of DMD, the splice sites that were removed using CRISPR technology instruct the genetic machinery to build abnormal dystrophin molecules. Once these sites are removed, an improved dystrophin protein was observed. Even more fascinating, correcting only half of the damaged cells restored cardiac function to a healthy level. Does this sound fascinating? If you answered yes, click here to learn more!

What Does the Future Hold?

The strategy of single-cut editing may be useful for treating other single-gene diseases. News of such prospects has generated a great deal of hope for patients. Much more research is needed before CRISPRCas9 can be used on human patients. Labs and researchers around the world are working to perfect this method so that it can get federal government approval and move to the next stage – human trials. As research progresses, it will be faced with backlash from some who believe DNA should not be altered and that the technique is too risky and support from those who believe this new technique could save lives. Which side do you fall on?

How Ground Squirrels Are Bracing For The Cold

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On January 2, 2018

In Student Post

https://www.flickr.com/photos/mandj98/7647426240

As we enter the heart of winter, puffy coats, hats, and gloves make it out of our closets to protect us from the frigid air. While we trudge along shivering, the ground squirrel lives happily in the cold weather, resistant to the low temperatures.

The Phenomenon:

A new study shows that when the ground squirrel wakes from hibernation, it is less sensitive to the cold than its non-hibernating relatives. Why? A cold-sensing protein, TRPM8, in the sensory nerve cells is partly responsible for the amazing phenomenon.

The Evidence:

In an experiment conducted with mice (non-hibernating), ground squirrels, and Syrian hamsters (hibernating animals closely related to the ground squirrel), the animals were given the choice between a hotter plate and a colder plate. Whereas the mice gravitated toward the hot plate, the ground squirrel and Syrian hamster did not react to the cold temperature of the plate until it dropped below 10 degrees Celsius.

The Biology:

Part of the squirrel’s and hamster’s intolerance to cold has to do with the TRPM8 protein. TRPM8 is a cold-sensing protein that sends a signal to the brain when something is too cold. Researchers turned to the gene responsible for turning on the TRPM8 protein to find the differences between a ground squirrel and a rat. They found a chain of six amino acids in the squirrel gene that caused the adaptation to cold. When they switched that section with one from a rat, the squirrel was more sensitive to the cold.

It is quite amazing that scientists can extract and switch such small portions of DNA to find the exact cause of a trait. What else do you think this technology could be used for?

The Effect on Life:

Tolerance to cold may help the squirrel and hamster transition from an awake state to hibernation state. This is true because if an animal senses or feels cold, it will expend a lot of energy trying to warm itself up. This process counters they physiological changes needed to transition into hibernation, a state of low metabolic activity. Hence, since the hamster and squirrel don’t sense the cold, it will be easier to hibernate.

Further Research:

There is still a lot unknown about the TRPM8 protein and ground squirrel temperature sensitivities. It is believed that TRPM8 is only a part of their intolerance to cold. Furthermore, the structure and function of TRPM8 is still being studied and could lead to more breakthroughs. Want to learn more about ground squirrels, hibernation, or the TRPM8 protein? Click here to read the full article!

Scraping Your Knee at 12:00am vs. Scraping Your Knee at 12:00pm: What’s the Difference?

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On December 10, 2017

In Student Post

https://www.wikihow.com/Use-a-Band-Aid#/Image:Use-a-Band-Aid-Step-5.jpg

By the time you reach the age of five, you’ve probably scraped your knee more times than you can count. Now, think back to the last time you fell off your bike or stubbed your toe during the day and the last time you did the same at night. Do you remember a difference? Chances are, you weren’t paying close enough attention, but there are scientists who were, and they have come to an interesting conclusion. According to a new study from England, nighttime injuries take longer to heal than daytime injuries, 60% longer to be exact! Why? It all has to do with the biological clock and the 24-hour cycle of cardiac rhythms of skin cells.

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

The Healing Process

Fibroblast skin cells are found in the deepest layer of the skin called the dermis. Check out the picture on the left for a close up view! When an injury occurs, fibroblasts travel to the surface of the skin, where their job is to synthesize and build the structural support of the new skin. How fast the fibroblasts travel to the surface depends on the time of day and the biological clock. Actin, a protein that forms the supportive structure of the cytoskeleton and gives a cell its shape, is the reason behind this difference. Ned Hoyle, a molecular biology researcher, studied the changes in actin over time, and came to the following conclusion: during the daytime, actin is in the form of long filaments, while at night, actin is in globular form. Actin filaments are crucial in helping cell moves, so when actin is in globular form, it takes longer for the fibroblast cells to travel to the surface of the skin.

The Evidence

The team of researchers conducted experiments on mice, which exhibited the same affect they had studied previously – the healing time at night is longer than during the day. Next, the team turned to humans, studying burn patients. From hospital records, they concluded that on average, burns that occurred during the day healed within 17 days, whereas burns that occurred at nigh healed within 28 days. However, there are still a lot of unknowns. Scientists predicted that the fibroblasts would make up for lost ground during the day, but in reality, the cells wounded during daytime never catch up.

What’s Next?

Although we can’t plan when we get hurt, this research is extremely important. Hoyle said that this research could be expanded to trying to make cells think its daytime, if a procedure takes place at night. Furthermore, he hopes to conduct more research on the complex process of healing and blood clotting. To check out their full study, click here!

Design Your Own Organelle!

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On October 11, 2017

In Student Post

What?

All eukaryotic cells consist of compartmentalized organelles, each with a specific function. We’ve all heard of mitochondria, chloroplast, and lysosomes, but, what if we could design a new organelle?! That’s exactly what scientists are working on right now – modifying or hijacking existing organelles to fit new specific functions.

Why?

Scientists currently have the technology to alter the DNA of cells to manufacture proteins they couldn’t “naturally” make. However, this technique has a few flaws. The proteins produced or their intermediates could damage the cell and chemicals in the cell could damage the proteins. If we could compartmentalize the production of these new proteins, this problem would be avoided. So, we look to organelles!

How?

Stuart Warriner, a chemical biologist at the University of Leeds, and his colleagues believe peroxisomes are the key. Current techniques allow scientists to manipulate these organelles. Their experiments show that they could deliver certain proteins into the peroxisomes of most cells. These selective proteins are ones that are not usually made; therefore, we say that humans have “hijacked” the cell.

https://commons.wikimedia.org/wiki/File:OSC_Microbio_03_04_Peroxisome.jpg

What’s Next?

Scientists are hopeful that future research could lead to the ability to use peroxisomes to manufacture compounds by importing specific proteins into them. Currently, when an organelle is modified, every organelle of that type must be modified. Future research could ensure that modified and conventional organelles could coexist in the same cell. In addition, Warriner and his team are working on the modification of peroxisomes in yeast to produce desirable compounds. Despite these studies, Warriner believes that this technique of hijacking organelles will not be implemented in humans for decades, if not never, because it wouldn’t be particularly useful. To learn more, check out their findings!

Who Cares?

We have the ability to alter DNA and cells! That is amazing! Although peroxisome altercation may not prove to be essential to humans, it is still an impressive exploratory feat and a step toward greater modification in microscopic organisms. What do you think similar cell modification research should be focused on?

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