Cuttlefish Ink: The Secret to Outsmarting Sharks

         Cuttlefish have an escape plan when they are approached by predators, they release a cloud of dark ink. While the ink does help hide them, it also has a strong odor that drives sharks away. The chemicals that give blood a strong scent to sharks is weaker than the ink.  One of the main elements that make up the ink is melanin, it sticks really well to the smell receptors in sharks. Researchers looked deeper into the genetics behind how sharks sense of smell works. They gathered genetic data on three shark species - the cloudy catshark, small-spotted catshark, and great white shark, this would model the shapes of 146 different odor receptors. Sharks have 45 smell receptor genes which is not a lot compared to mammals who have somewhere around 850. What that means for the sharks is that they can detect fewer types of odors but are very sensitive to the ones they actually can smell. When scientists modeled how melanin interacts with these smell receptors, they found that it binds really tightly to the receptor. Because sharks are already sensitive to scents the ink is very overwhelming for them driving them away. The melanin's ability to bind so tightly to the receptors is why the sharks react more to the ink than the metallic smell of blood. 

    I think this article is a very interesting example of how evolution can improve the survival skills of animals. Its amazing that a fish that is on the smaller side can get sharks to leave an area because of the ink's odor. I never realized scientist could just make models of smell receptors using the genetic information from different types of sharks to demonstrate how certain component impact the sharks behavior. In this case it was melanin which i also learned gives the black color to the ink. This article kept me very engaged because of the way they connected animal behavior with genetics. It made me realize that something as simple as ink can be a product of natural selection. 

The Autosomal Recessive Inheritance and X-Linked Inheritance Pattern of Albinism

     Albinism is the topic discussed throughout the article, 'Everything you need to know about Albinism,' as well as delves deeper into the types of albinism, symptoms, causes, diagnosis process, treatments, and the complications that may come with being diagnosed with albinism. First, the article describes albinism as a heritable condition in which the body produces substantially low rates of melanin to no melanin; thus, an individual with little to no melanin lacks all pigments that color skin, hair, eyes, etc. This results from genetic mutations in the genes that produce melanin, such as TYR, OCA2, TYRP1, and SLC45A2, resulting in this lack of pigment.  Individuals with the condition have paler complexions and lighter skin and hair tones than other family members of their ethnic or family heritage, problems with eyesight, sensitivity to UV light/ sun exposure, and higher risks of developing skin cancer due to the effects of lack of melanin that this condition causes. There are two main types of albinism: ocular albinism (OA)- in which the eyes are primarily affected, and oculocutaneous albinism (OCA)- affecting the skin, eyes, and hair of the individual. However, there are seven subdivisions between the two main types of albinism. These subdivisions are categorized by how mild to severe the symptoms are, i.e., OCA type one, two, three, and four, X-linked ocular albinism, Hermansky-Pudlak syndrome, and Chediak-Higashi syndrome. Although albinism can affect anyone, there has been a regional correlation to the condition. Albinism is estimated to affect one in every 2,000-5,000 individuals in sub-Saharan Africa. Whereas, in Europe and America, the rate of albinism is roughly one in every 17,000-20,000 people. 

    Symptoms of albinism can range from extreme to mild: lighter skin tones (levels of melanin may slowly increase over time), darkening the skin tone over time, as well as UV sensitivity resulting in freckles, moles, or lentigines.  Hair color may also follow the broad spectrum trend, resulting in some individuals having white to brown hair, over time, as the individual ages, their hair may slowly darken due to an increase in melanin production. An individual's eye color may range from very light blue to brown but also change with age-- in some cases, the eye color may appear red or pinkish, typically caused by the low levels of melanin in the iris and light reflecting off the retina at the back of the eye. This lack of pigment in the eye may result in an individual to be light sensitive. Finally, vision may also be affected to a certain degree. Nystagmus, Strabismus, Amblyopia, Myopia/ Hypermetropia, Photophobia, Optic Nerve hypoplasia, Optic Nerve misrouting, and Astigmatism are all possible changes to eye functions that someone struggling with albinism may incur. There is no cure for the condition of albinism. However, treatments may be implemented to minimize the symptoms and aid in bettering an individual's everyday life who struggles with this condition. 

    Albinism is genetic. Generally, most albinism is a result of autosomal recessive inheritance patterns. However, albinism can have an X-linked inheritance pattern. With autosomal recessive inheritance, an individual must receive copies of the mutated gene (recessive gene) from both a maternal and paternal donor, in this case, to develop albinism. If parents are heterozygous for the trait, and the dominant allele is expressed over the recessive allele, typically making them "carriers" of the trait. Thus, they do not display any symptoms of albinism. If the parents are both heterozygous and carry the allele for albinism, there is a one-in-four chance that the offspring will have albinism. In cases where albinism is a result of X-linked inheritance, males are mainly affected. Simply because females carry two X chromosomes, if one X chromosome is damaged or mutated, the other X chromosome offsets the issue and will be expressed instead. Whereas males have an X and a Y chromosome, meaning any albino mutation in their singular X chromosome will be expressed and generate the condition. 

  
I chose this article because although I know albinism is a prevalent condition, I do not personally know anyone who has been diagnosed with it. Due to this, I only knew the visible symptoms of the condition, not any of the biological causes of the condition, the different types of albinism, the genes involved, and so on. This made researching and reading more about the topic more interesting and informative. Prior to reading this article, I never knew that albinism could be a result of two different inheritance patterns: autosomal recessive inheritance patterns or X-linked inheritance patterns. In addition, the specific genes that affect melanin production, thus, when these genes become damaged or mutated, these genes can't produce sufficient melanin or pigments, resulting in albinism. 

The Power of Synthetic Melanin to Enhance Skin Healing

        The never ending fight against free radicals might come to an end. Scientists at Northwestern University successfully developed synthetic melanin that's applied in a cream. Headlines of a skin cream that can not only protect the skin from the sun but also accelerates wound healing. Sounds like a good investment. 

        The synthetic melanin is modified to have higher free radical scavenging capacity. In other words, aid effectiveness in neutralizing free radicals to protect cells and tissues from damage. In the context of melanin, this is crucial as many obstacles such as UV exposure can disrupt melanin production. Eventually pose risk for skin related issues such as skin cancer. 

        Equally important, the synthetic melanin acts as a super melanin. With amazing results shown for topical applications to injured skin and effects with the immune system. Not only healing and protecting the skin. But has the ability to allow the body to have a calming effect and lower rates of inflammation. As scientists call this super melanin, who is this powerful cream for? Clinical trial testing is currenting ongoing to test for efficacy of the synthetic melanin cream. However, this cream can act as a sunscreen, treatment for poison ivy, treatment for wound care and cancer patients. Synthetic melanin cream is versatile, offering a one-size-fits-all solution that caters to a broad spectrum of applications.

 Links:

https://www.sciencedaily.com/releases/2023/11/231102135130.htm

https://www.science.org/content/article/synthetic-super-melanin-speeds-skin-repair

https://www.youtube.com/watch?v=yLau91eVD-I&embeds_referring_euri=https%3A%2F%2Fnews.northwestern.edu%2F&embeds_referring_origin=https%3A%2F%2Fnews.northwestern.edu&source_ve_path=MjM4NTE&feature=emb_title

The Effects a Person's Genetic Coding has on Their Ability to Tan

    Whether someone says it or not, when school ends in May everyone has a goal to come back in September tan enough to turn some heads. For some people, it's easy. They can go to their local swim club, lay out for a couple hours a week and achieve tan skin. In contrary others can sit on the beach everyday for a week and end up like this guy. What is the reason for this? Does a person's DNA encoding play into their tanning success? According to Geneticist Marina Sumarocca of Stanford University there are two main factors that come into play when determining someone's susceptibility to tan, burn, or nothing. The first is your natural skin color, the second is your skin's natural response to sunlight. The body's natural skin color is determined based off the body's production of a pigment called melanin. The more melanin in a person's body, the darker their skin is. There are dozens of genetic codings that play into how much melanin is produced by melanocytes, this is why it is so rare to find someone with the same exact skin tone as you. When you sit in the sun all day at the beach, UV Radiation is coming from the sun and your skin is absorbing it. This is what causes either a tan or burn. Melanin can be seen as natural sun screen, if you produce a lot of melanin you will naturally have a dark complexion. This person's body is more equipped to absorb UV radiation, thus a burn does not appear. Whereas someone who has a pale skin tone, and does not have much melanin in their skin would produce a gnarly burn on their body. 

    In the past 50 years, medical advancements have been made on the knowledge of skin cancers. There are three primary skin cancers, cutaneous malignant melanoma, basal cell carcinoma, and squamous cell carcinoma. In the past half century the amount of skin cancer diagnoses has tripled. This is not because people are in the sun more, just that doctors and geneticists are now able to identify unusual markings on the skin easier than before. The cause for these skin cancers directly comes from mutations caused by UV exposure. UV radiation can come from other places besides the sun, like tanning beds. In a study done by physicians, 61 of 63 women diagnosed with melanoma before the age of 30 had used tanning beds. 

Link: https://genetics.thetech.org/ask-a-geneticist/does-ability-tanburn-have-something-do-genetics

Link:https://medium.com/genome-link/how-is-tanning-ability-encoded-in-your-dna-a6b11a3f81d5#:~:text=According%20to%20the%20study%20we,susceptibility%20is%20not%20fully%20understood.

Link:https://www.skincancer.org/blog/5-myths-indoor-tanning-busted/

Melanin in Manta Rays

There are only two species of fish with dark melanin spots on their skin. Both of these species are manta rays. Some manta rays exhibit dark spots on their otherwise completely white underbellies. These dark blotches are caught the eye of researches for that reason. They figured that there must be a reason that melanin is so rare in the ocean and there must be a reason that rays express it.
 
Manta rays have very few known predators. One theory that offers an explanation as to why is that their white underbellies makes them difficult to see against the sky. In that case, the dark spots should be selected against. After following a population of melanistic rays, the researches determined that the dark spots do not affect fitness.

It is also possible that the gene causing this mutation is closely linked with another gene which is improving fitness. Perhaps there is an advantage within the manta rays that we cannot see which has the side effect of these dark splotches. However, as mentioned earlier, initial research shows that these spots do not appear to affect fitness.

Their new hypothesis is that the mutation may be a product of genetic drift. Not all populations of rays have this trait. Some have up to 40% while others have nearly none. It is believed that this neutral trait appeared as a mutation in a population and increased in frequency through random chance. The members of this population mated with other populations, spreading the gene further. If that is the case, this gene can be used to traced back through several generations and better understand migration habits of manta rays. Rays are currently a vulnerable species. Being able to predict where they will go may help the conservation effort. I hope that they find success in the conservation endeavor because mantra rays are an awesome animal that I want to see more of in the future.

Links:
https://www.nytimes.com/2019/10/14/science/manta-rays-black.html?searchResultPosition=14
https://marinemegafaunafoundation.org/blog/scientists-explore-the-occurrence-of-black-manta-rays-in-the-indo-pacific/

blue eyed humans have a single common ancestor

In an article from Science Daily, a study shows that people with blue eyes all share one common ancestor. 6-10,000 years ago a genetic mutation took place which is the cause of the eye color of all blue eyed human beings alive on the planet today. Variation in eye color from brown to green comes from the amount of melanin in the iris. People with blue eyes only have a small variation in the amount of melanin in their iris. Which has drawn scientists to conclude that they all come from the same ancestor. Originally we all had brown eyes, but a mutation in the OCA2 gene in our chromosomes resulted in a switch which turned off the ability to produce melanin in the eyes.

 However, the mutation only affected the ability for the body to produce melanin in the eyes without affecting a gene adjacent to it which would have affected the body’s ability to produce melanin at all resulting in albinism. This mutation however has neither positive nor negative effects on the body and is a perfect example of nature trying new things.

Eye Color; Myths of Genetics

There are many myths regarding genetics and inheritable traits. Even when most of them have been clarified, people are still confused about some patterns of heredity. One of the most popular myths of genetics is eye color, specially those in the blue category since it is less common.
People used to believe that eye color were single genes, and that blue is a recessive allele of other non-blue eye colors like greens and browns. A research on myths of human genetics by John McDonald notes that eye color is not a simple hereditary trait, in fact there is at least 12 genes involved and phenotypes vary not only with the genes themselves but also with the interactions with each other.

Heterochromia: Different pigmentation/concentration of melanin.

Many articles explain that the coloration of the eyes is mainly based on the presence and absence of melanin, and that essentially there is only one eye color, brown; other colors are a product of reflection and absorption of light. Melanin is a brown pigment that absorbs light; in blue eyes, there is less melanin thus more light is reflected. For eye color, there are genes that determine the melanin's quality, quantity, dispersion, concentration, etc. Other factors like the amount of collagen in the iris and blood vessels can also affect the color expressed. Eye color is still believed to be genetic but is more complicated than simple dominant-recessive alleles.

So, Where do Eye Colors Really Come From?

The colored part of the eye is called the iris, and the dark center is known as the pupil. So, what makes the iris appear as a certain color? Maybe brown, hazel, green or blue? Eye color is pieced together by different portions of certain pigment and the tissue that makes up part of the iris. The pigment expressing cells of the iris are known as melanocytes. They can create two different pigments: eumelanin (brown-black) or pheomelanin (red). You can see here that there is no pigment for blue eyes. Blue eyes are formed due to white collage fibers in the iris tissues. Dark eyes are formed from a large amount of pigment, while the blues and greens form from low amounts of pigment.
An article published on Medical News Today, explained that an eye color is made up of many more than just one gene. In fact, the eye color is made up of about eleven genes! Although we know that eye color is inherited from the parents, eleven genes are involved for this one single traits formation. Researchers at Erasmus University Medical Centre Rotterdam did a study on genetic variants in the eleven genes of over 3,000 people. "When they compared these genetic profiles with a new method of assessing eye color in photographs - which was developed as part of the study - the team could reliably predict eye color in most cases."
There is still ongoing research to determine all genes incorporated in the creation of eye color and pattern, but the information obtained as of now is still fascinating. I really enjoyed reading this article. This is such a neat study because most people believe that eye color is passed on from parent to child through a simple gene. It is interesting to learn that there are actually 11 genes involved in this process! This is also very interesting to me because it is possible for two parents with brown eyes can have a child with blue eyes. It all leads back to science.

Optix gene responsible for butterfly wing color

New genes are being discovered more frequently than ever. Scientists have found genes responsible for anything from your height to eye color. In regards to eye color, in humans, the genes associated with eye color can have mutations that cause different eye color (such as green eyes) or the absence of eye color (albinism). However, sometimes you want to change your eye color, perhaps you want to go bold and have purple eyes. So you get contacts. But what if there was a way to control what eye color you want? According to an article on The New York Times, scientists have located two "master genes" that are responsible for how butterflies get their wing color. One of these genes is called optix. It is the gene that is responsible for the pigmentation of butterfly wings. What scientists found was that if the gene was removed from the eggs of a certain type of butterfly, then there would be a different pigmentation in the wings of the butterflies. It was found that the melanin that was controlled by the optix gene created a different color, hinting to the idea that melanin is connected to the optix gene, and produced a different color. Scientists were also looking at gene called WntA, which is responsible for the patterns of the pigmentation to appear on the wings of butterflies. When this gene was deleted, then there was an absence of pigmentation in the patterns of the wings.

I personally find this study to be very fascinating. It makes me wonder if we would be able to do this with humans in the near future. However, I wonder if we would be able do this, would it be a cause for humans to have albinism, since the gene responsible for the melanin production in our eyes to become non-existent. I think it might become most likely become a very prominent phenotype if this would become successful, since the gene would have been removed entirely from original person. Overall, I find this study to be very interesting, and I wonder if similar procedures and experiments will be done in order to alter the appearance of humans and other animals.

Blue-eyed humans have a single, common ancestor

A genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a switch, which turned off the ability to produce brown eyes. The OCA2 gene codes for the so-called P protein, which is involved in the production of melanin, the pigment that gives color to our hair, eyes and skin. Variation in the color of the eyes from brown to green can all be explained by the amount of melanin in the iris, but blue-eyed individuals only have a small degree of variation in the amount of melanin in their eyes. From this we can conclude that all blue-eyed individuals are linked to the same ancestor, says Professor Eiberg. 
I think mutation of brown eyes to blue represents neither a positive nor a negative mutation. It is one of several mutations such as hair color, freckles and beauty spots. I think this simply shows that nature is constantly mixing the human genome, and creating all sorts of possibilities. 

https://www.sciencedaily.com/releases/2008/01/080130170343.htm
http://news.ku.dk/all_news/2008/blue-eyes/

Did You Cause Your Parents’ Gray Hair, Or is Genetics to Blame?

The answer is actually believed to be an interesting mixture of both. Gray hair is due to a loss of pigmentation. Hair pigments are composed of melanocytes, which are responsible for implanting melanin into the keratin-containing cells of our hair. A plausible explanation for gray hair could be due to deterioration of the melanocyte cells, resulting in less melanin in the hair proteins. Also, environmental factors such as stress and shock can increase graying hair, though this concept is still not completely understood.

But why do single gray hairs appear in the start of the graying process? Due to the fact that each hair follicle grows independently, individuals tend to exhibit single strands of gray hair before the entire head turns to gray.

Recently, a team of researchers in Europe discovered that catalase, an enzyme involved in the breakdown of hydrogen peroxide, is responsible for causing vitiligo. This genetic disorder is characterized by patches of skin that lack pigment. Because gray hair also results from loss of pigment, researchers believe the accumulation of hydrogen peroxide may be a reason for graying hair. The cell only produces a small amount of the chemical, but this can create a build up over time. The researchers believe that these elevated levels of hydrogen peroxide block the synthesis of melanin. Knowing the process behind gray hair puts scientists one step closer to identifying the relationship that stress plays as well. Regardless if scientists find a correlation between stress levels and the graying process, its ultimately believed that genetics are the primary determining factor.

An understanding of the mechanisms behind gray hair is not just interesting, but has the potential to uncover the secrets behind aging on a molecular perspective. Perhaps the device responsible for destroying hair pigment cells could aid in destroying the cells responsible for cancer, leading to more effective treatment options for melanoma in particular.

Primary Article

Secondary Article