BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: #geneticstudies

Can we make Jurassic Park real?

CRISPR technology has already demonstrated its potential to revolutionize modern biology. Summarized, CRISPR is a gene editing technology. It has the ability to change the sequence of DNA in living cells, therefore changing their traits. However, the applications of CRISPR extend far beyond simple fun with gene editing. CRISPR can be used to modify the foods we eat, making them easier to grow and more resistant to harsh climate. CRISPR has even been theorized to have implications for treating human genetic diseases. However, how far does this technology go?

Dino Park

A group of scientests have been focusing on a much more radical side of CRISPR: they are attempting the revival of an extinct species. The Christmas Island Rat went extinct over 100 years ago in 1903. Thankfully, some DNA of the rat has been maintained, allowing scientists to sequence the genome. Through analysis, they have found that the Christmas island rat is very closely related to the brown rat. In fact, the genomes have a 95% similarity between them. This similarity begs the question, can we CRISPR a Brown Rat into a Christmas Island Rat?

Because of the highly similar genomes, scientists believe that they can use the gene editing technology in CRISPR to recreate the Christmas Island Rats from the brown rat. While they have not yet achieved their goals, they are confident in their ability to produce results. Although modifying a rat to bring back a close relative is a long way off from bringing back dinosaurs from nothing, this amazing experiment may pave the way for future scientists to make the movies real life. As science progresses, we may be able to transform more complex and distantly related species, we will just need to wait and see.

A Vision For a Better Future

CRISPR is a world changing technology that is essentially used to edit genes. The discovery of CRISPR took place in the University of Alicante, Spain. Reported in 1993, Francisco Mojica was the first to characterize CRISPR locus. Throughout the 90s and early 2000s, Mojica realized that what was once reported as unique sets of repeat sequences actually shared common features, which are known to be hallmarks of CRISPR sequences. Through this finding, Mojica was able to correctly hypothesize that CRISPR is an adaptive immune system. In the year 2013, Feng Zhang, was the first scientist to successfully adapt CRISPR-Cas9 for genome editing in Eukaryotic Cells. Zhang was able to engineer two different Cas9 orthologs and he then demonstrated targeted genome cleavage in both human and mouse cells. They discovered that this system could then be used to target multiple genomic loci and could also drive homology directed repair.

CRISPR-Cas9 mode of action.png

How Does it Work?

“Clustered regularly interspaced short palindromic repeats,” also known as CRISPR, are repeats found in bacteria’s DNA. CRISPR-Cas9 was adapted by scientists from a naturally occurring genome editing system in bacteria. This bacteria captures parts of DNA from invading viruses and it uses them to create DNA segments known as CRISPR arrays. This DNA allows the bacteria to recognize and remember the virus’s. If the same virus, or a similar one, attacks again, the bacteria will consequently RNA segments in order to target the viruses DNA. After, the bacteria uses the enzyme Cas9 in order to cut the DNA apart, thus disabling the virus. Scientists in a lab will create small pieces of RNA that attach to a specific target sequence of DNA and also the Cas9 enzyme. In this process, the RNA is used to recognize DNA and the Cas9 will cut the targeted DNA. Once cut, researchers will utilize the cell’s ability to repair DNA in order to add or remove pieces of genetic material. It can also replace existing DNA with custom DNA in order to make changes.

How is it used?

CRISPR is a tool that can be used to fight cancer among other known diseases. The therapy involves making four modifications to T-cells. T-cells are cells that help fight cancer. CRISPR adds a synthetic gene that gives the T-cells a claw-like receptor. This receptor can locate NY-ESO-1 molecules on cancer cells. CRISPR is then used to remove three genes. Two of the removed genes can interfere with the NY-ESO-1 receptor and the third limits a cell’s cancer killing abilities.

Another way CRISPR is used is against Leber’s Congenital Amaurosis(LCA). LCA is a family of congenital retinal dystrophies that results in vision loss. Patients tend to show nystagmus, sluggish pupillary responses, decreased visual acuity and photophobia. The CRISPR trial focuses on one gene mutation that causes a severe form of degeneration. It is said that this mutation creates somewhat of a “stop sign,” and RNAs will target sequences on either part of the stop sign. The Cas9 enzyme will then cut them out, allowing the DNA to then repair itself.

Do Genetics Play A Role In Attraction?

Have you ever met someone with whom you instantly wanted to be friends but couldn’t put your finger on why or how you felt so drawn to them? There is a reason why you might be drawn to a specific person or group of people that may be explained by biology.

Double stranded DNA with coloured basesChromosome Terminology

According to a book by a well-known author, Malcolm Gladwell, a “unconscious” region of the human brain helps us to digest information spontaneously while encountering someone or something for the first time or making a rash decision. The University of Maryland School of Medicine has expanded on this hypothesis with a new study, indicating that these reactions may have a biological foundation related to heredity. The experiment was carried out on a group of mice. Variations in a particular enzyme discovered in a portion of the brain that affects mood and drive appear to influence which mice desire to actively engage with other mice; genetically related mice favored one another. Similar circumstances, such as disorders linked with social withdrawal, such as schizophrenia or autism, might also influence people’s decisions. Consequently, researchers do not agree with the phrase “opposites attract,” because genetics have a significant role in attraction. Instead, experts propose that we choose friends based only on their similarities to ourselves. Unlike the concept of “opposites attracting,” the expression “people like their own kind” is accurate. While genes definitely contribute to an individual’s attractiveness, they only account for around one-third of the reasons why we choose someone else to be our friend.

In a separate study, researchers examined a range of variables, that often are most inheritable and those that are less inheritable, to evaluate the role genes function in our human conduct, and they discovered that “people are genetically inclined to choose as social partners those who resemble themselves on a genetic level.” Rushton discovered in this study that humans prefer to choose partners based on inheritable attributes, even when we are unaware that such characteristics are genetically determined. For example, the middle-finger length is inherited, although the upper-arm circumference is not. Spouses who took part in the study had identical middle finger lengths but not the same upper-arm circumference. The function of heredity also influences personality, which explains why “people like their own kind.” What you inherited biologically from your parents, which is defined by the genes in your DNA, is the key to personality traits. Genetic heredity accounts for almost half of our cognitive differences, from personality to mental capabilities.

Love-heart-hands

Genetics is the scientific study of genes and heredity, which transfer particular characteristics from parents to offspring due to variations in DNA sequences. The genome contains all of an organism’s genetic code, including its genes and additional components that govern the activation of those genes. We are drawn to others because of the features that we share with them through genetic material. Our DNA is stored in chromosomes, and each of the 23 pairs of chromosomes has the same genes that are handed down from parent to offspring. When a baby is being formed, DNA is handed down, and each parent sends half of their chromosomes to their kid, thus each of your parents contributes 50% of your DNA. The term “genetic love” refers to the idea of matching partners for romantic relationships based on their biological compatibility. “Genetic love” describes the notion of attraction based on heredity.

Difference DNA RNA-EN

Is it possible that you want to be friends with someone of the same genetics as yourself? Yes! It is! However, it is not the only thing that accounts for maintaining a friendship.

Race is a Social Construct. Science cannot be Misused to Justify Racism.

This blog post from Montclair HS in NJ, co-written by a teacher and a student is very insightful through its thorough exploration of the biology of melanin as well as some helpful links in its introduction of genetics and race. 

Melanin is a pigment found in our skin whose job is to protect us from harsh conditions such as sunlight (specifically the radiation from rays that can damage DNA and increase risk of skin cancer). Those with higher levels of melanin tend to have darker eyes and those with lower levels have lighter eyes. In addition, there are two types of melanin called eumelanin and pheomelanin. Eumelanin (in higher concentration) is responsible for darker shades in eyes, hair, and skin while pheomelanin (in higher concentration) is responsible for lighter shades.

The topic then shifts to the idea of skin color losing its biological importance. It contributes to the creation of race and its value. When science mixes with societal constructs, things can get complicated. Through science, we obtain knowledge backed by evidence. What happens if bias interferes? I’d question the accuracy of the information I consume. Science should not be utilized to push forward personal agendas nor should it be used to justify things like racism. The blog links an article covering misrepresentative genetic data and how it can be used to support one’s view. The article references a 2017 gathering of white nationalists chugging milk, because digesting lactose as an adult is a genetic trait more frequent in white people. However, this stems from a racially charged past. Other minorities were excluded from this evolution, yet this trait is commonly used to tell those of African descent to leave America. While certain findings appear to have one meaning, we must be careful to not fixate on how we want to use information to support our own opinions. Part of this responsibility belongs to scientists and how they present their data. Many doubt their ability to communicate to the public about controversial topics. All humans are 99.6-99.8% identical. That as a fact is the basis of why I believe there aren’t superior or inferior people.

 

This glass of milk may be cool, but white supremacy isn’t. The genetic trait to be able to digest lactose after childhood is far more common in white adults. However, this is not due to racial superiority in any way. There was a chance mutation that not everyone experienced because of discriminatory conditions during the time period.

The American Medical Association implemented two policies as of November 16, 2020. The policies acknowledge race as a social construct. Racial essentialism – when race is considered a biological construct – worsens health disparities for marginalized groups. Therefore the AMA desires medical education that can explain how racism is able to grow when race is presented as biology. It is their hope that race can one day no longer be a determinant of health.

This blog piqued my interest, because I often forget that identifiers such as race and gender are social constructs. These articles were a perfect combination of what some of my Diversity Committee work is but also what we have been learning in AP Bio about genetics. I think it is so important to address these areas of bias within our systems in this country. Racial inequality has been prevalent for far too long. We must use science for the greater good and not to support each personal opinion we have.

Powered by WordPress & Theme by Anders Norén

Skip to toolbar