BioQuakes

AP Biology class blog for discussing current research in Biology

Author: jillosis

Our close cousins, Denisovans

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On May 1, 2018

In Student Post

Denisovans

Evolution is the change in the heritable characteristics of biological populations over successive generations. Evolutionary processes give increase biodiversity at every level of biological organization, including the levels of species, individual organisms, and molecules.

We once thought that the neanderthals were the only relatives but recent studies show that the Denisovans also interbred with humans.

This picture represents the spread of the Denisovans.

Modern humans are now the only human lineage left alive but others not only lived alongside modern humans, but also interbred with them, leaving behind DNA in the human genome. But with enough evidence, it has been proven that the mysterious Denisovans are relatives of modern humans. Denisovans also harbor a small amount of especially exotic DNA, probably from breeding with “super-archaic” humans that split from the others over 1 million years ago.

Previous research discovered that while Denisovans shared a common origin with Neanderthals, they were just as genetically distinct from Neanderthals as Neanderthals were from modern humans.

This diagram shows the spread of human.

According to researchers, ancestors of Oceanians interbred with a southern group of Denisovans, while the ancestors of East Asians mixed with a northern group.”The implication is that there were at least three instances of modern humans interbreeding with archaic humans — one with Neanderthals and two with Denisovans,” Browning said. “To me, this suggests that modern humans weren’t so very different from Neanderthals and Denisovans. There are signs that intermixing with archaic humans was occurring in Africa, but given the warmer climate, no one has yet found African archaic human fossils with sufficient DNA for sequencing,”

 

 

CRISPR-cas9: Coming to a Human Near You

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On March 10, 2018

In Student Post

CRISPR

What is CRISPR?

As the world becomes more technologically developed, CRISPR is a new and upcoming technique to genetically edit genes. Being able to alter DNA sequences and revise gene roles, scientists now have the ability to correct defects, prevent diseases/mutations and improve genes overall.  As time goes on, scientists now feel that they are ready to genetically alter humans.

This image represents what CRISPR is capable of. The two wrenches represent that CRISPR edits the DNA strands and creates new and improved DNA.

How does CRISPR work?

CRISPRs are specialized stretches of DNA recognized by the protein Cas9. Cas9 is an enzyme that acts like a pair of molecular scissors, capable of cutting strands of DNA. Without that enzyme, CRISPR would not be successful.

CRISPR stands for “clusters of regularly interspaced short palindromic repeats.” It is a specialized region of DNA with two obvious characteristics

  1. the presence of nucleotide repeats and spacers.
  2. Repeated sequences of nucleotides — the building blocks of DNA — are distributed throughout a CRISPR region.

Spacers are bits of DNA that are interspersed among these repeated sequences.

***According to livescience.com, there is a built-in safety apparatus, which guarantees that Cas9 will not cut anywhere in a genome. Short DNA sequences become tags and stay adjacent to the target DNA sequence. If the Cas9 complex doesn’t see a short DNA sequence next to its target DNA sequence, it won’t cut.***

Is this really safe for humans?

Not too long ago, a study by Columbia University Medical Center was published in May, in the journal Nature Methods, about this “revolutionary” CRISPR gene-editing technique. It claimed that CRISPR caused unwanted and dangerous mutations and left the medical community baffled. The paper questioned how effective gene-editing technology is and called for a reassessment of the technique’s safety. However, this publication has to do with how CRISPR was first tested: 3 mice and very controversial results. Editage.com stated that “two of the three study subjects, the CRISPR-edited mice, happened to be more closely related and thus shared more mutations. Therefore, the paper claimed that “the premise of the old study was incorrect.”



If you have the choice, will you use CRISPR to design your children? Comment!

White Nose Syndrome

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On January 18, 2018

In Student Post

White Nose Bats

What causes the disease?

Exposure to UV light is the cause of a devastating disease found in North America. According to USDA Forest Service, the disease”can only infect bats during hibernation because it has a strict temperature growth range of about 39-68 degrees Fahrenheit”. Bats are very sensitive to the ultra-violet light which causes the P. destructans fungal pathogen(any disease-producing agent) to trigger the disease.

A bat affected by White Nose Syndrome.

When is a bat most at risk?

During hibernation, bats face a high risk of the white nose syndrome. WNS officials claim that the bats act strangely during cold winter months, including flying outside in the day and clustering near the entrances of hibernacula (winter quarters for a hibernating animal).

Effects of WNS

Bats have been found sick and dying in unprecedented numbers in and around caves and mines. WNS has killed more than 5.7 million bats in eastern North America.

This bat is in hibernation and at risk of WNS.

What is being done?

A research team has identified in the pathogen an enzyme that repairs DNA causing the team to expose the fungi to DNA damaging agents, including different wavelengths and intensities of UV light. Consequently, they found that a low dose exposure of UV-C light resulted in about 15 percent survival of P. destructans.

Don’t be a victim of a pHatty diet!

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On January 3, 2018

In Student Post

 

Are you guilty of a pHatty diet?

What is the pH scale?

The human body can only function correctly with a pH level around 7.4. Foods such as fruits, vegetables, beans, and spices all can negatively contribute to poor health conditions because, due to their low pH levels, they are more acidic. If something is acidic, it is a substance that donates hydrogen ions; when an acid is dissolved in water, the balance between hydrogen ions and hydroxide ions is shifted and now there are more hydrogen ions than hydroxide ions in the solution. However if the substance is not acidic. it is considered a base. A base is is a substance that accepts hydrogen ions so when it is dissolved in water, the balance between hydrogen ions and hydroxide ions shifts the opposite way. Because the base “soaks up” hydrogen ions, there are more hydroxide ions than hydrogen ions. This kind of solution is alkaline.

pH Affects Health and Wellness

According to FoodandNutrition, because the kidneys and liver work to control the acidity levels but when big amounts of acidic food is consumed, it’s difficult for the body to accustom to the acidity which could be detrimental. It is important to understand that ” Lemon juice and tomatoes, for example, are acidic. But when ingested, they promote alkalinity. The pH of the actual food does not dictate the net effect on the body. Rather, it’s the “potential renal acid load” which measures acid in excretion/urine.

Even though there are parts of the body that can handle highly acidic materials, such as the stomach, it is important not to consume too much acid food because effects can be long term: : kidney stones, increased chance of cancer, liver problems and heart disease. A person is also at risk of acidosis which is a disease where your body fluids contain too much acid because the kidneys and liver are not functioning properly.  Symptoms of this are…

  • rapid and shallow breathing.
  • confusion.
  • fatigue.
  • headache.
  • sleepiness.
  • lack of appetite.
  • jaundice.
  • increased heart rate.

Here shows examples of liquids and where they fall on the pH scale. As you look down the scale, the liquids become more acidic but if you look up the scale, the liquids become less acidic.

What can you do?

To get away from a high acidic diet, you could try a plant-heavy diet with reduced refined sugar.  An example of a healthy meal with low levels of pH would be mushrooms, corn, beef and collard greens. It is really important to make sure you have a balanced diet, based on acidity, because the riscks are quite dangerous.

 

What do you think makes the human body not capable of consuming and maintaining large amounts of material with pH levels below 7.4?

Not to worry… you’re someones (blood) type!

By

On November 6, 2017

In Student Post

 

BLOOD

Blood types were first discovered in 1901 by Austrian immunologist, Karl Landsteiner. The classification of human blood is based on the inherited properties of red blood cells as determined by the presence or absence of the antigens A and B, which are carried on the surface of the red cells. So what is the difference between types A,B,AB and O blood?

This picture demonstrates the possibilities of different blood types and their characteristics.

 

Blood Type is Hereditary 

Hereditary is defined as genetic factors that are able to be passed on from parents to their offspring or descendants. If someone has blood type A, they must have at least one copy of the A allele, but they could have two copies. Someone who is type B must have at least one copy of the B allele.  Alleles are one or two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

Blood types are either positive or negative.  It is important to note that blood cells do not have a charge, the + or – is used to determind specific traits of the cell. For example, the + or – is determined on wether or not the blood cell has the antigen “Rh factor”. If there is a + attached to your blood type, the antigen is present; if there is a – next to your blood type, the antigen is not present.

So What?

Dealing with blood types is very interesting because, according to “Scientific American”, blood type may affect brain function as we age, concluded from a new large, long-term study. However those with AB show a 10% increase of having cognitive problems. From that same study, it was determined that…

In addition to blood types affecting health, blood types also contribute to a persons personality.  According to James and Peter D’Adamo’s work, type A tends to be cooperative, sensitive, clever, passionate and smart where type B people tend to be balanced, thoughtful and ambitious.

Blood type’s current impact on society is very crucial because it gives insight to future diseases, the ability to donate blood to those who need it, and for new born babies be a backbone for their personality.

Comment your blood type below!

 

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