Evolutionary Lies
- Lafyva
- Jul 26
- 7 min read
Updated: Aug 7
AI Overview
That's correct. HERC2 and OCA2 are not alleles at different loci on the same chromosome; instead, they are two distinct genes that interact to influence eye color. Specifically, HERC2 regulates the expression of OCA2, which is the primary gene responsible for melanin production in the iris. While they are located near each other on chromosome 15, they are not different forms of the same gene. Furthermore, they are not in linkage disequilibrium (LD); their variations are inherited together at a much higher rate than would be expected by chance, indicating a functional relationship rather than just physical proximity.
Here's a more detailed explanation:
Not alleles at different loci:
Alleles are different versions of the same gene, found at the same location (locus) on a chromosome. HERC2 and OCA2 are different genes, each with its own set of alleles.
Functional interaction:
HERC2 plays a crucial role in regulating the expression of the OCA2 gene. Specific variations in HERC2 can impact how much melanin OCA2 produces, affecting eye color.
Not in LD:
Linkage disequilibrium refers to the tendency of certain gene variants to be inherited together more often than would be expected by chance. While HERC2 and OCA2 are located close together on the chromosome and variations in these genes are often inherited together, they are not in LD because their close proximity is not the sole reason for their correlated inheritance. The functional relationship, where HERC2 regulates OCA2, explains why their variations are frequently inherited together.
Melanin and Eye Color:
The amount of melanin produced by melanocytes in the iris determines eye color. OCA2 encodes a protein called the P protein, which is involved in melanin production. HERC2 influences the amount of P protein produced, thus affecting eye color.
AI Overview
That's correct. HERC2 and OCA2 are not examples of disassortative mating. Instead, they are distinct genes that work together to influence eye color. HERC2 regulates the activity of OCA2, which produces the pigment melanin, resulting in the variation of eye colors.
Here's a more detailed explanation:
OCA2 (Oculocutaneous Albinism II):
This gene is a major player in determining eye color, specifically the amount of melanin produced in the iris.
HERC2 (HECT and RLD domain containing E3 ubiquitin protein ligase 2):
This gene interacts with OCA2 and acts as a regulator, influencing how much pigment OCA2 produces. A specific variant in HERC2 is linked to blue eye color.
Interaction:
The HERC2 gene contains a region that acts as an enhancer for the OCA2 gene, meaning it controls how much OCA2 protein is made. Variations in this region of HERC2 can affect how strongly the enhancer acts on OCA2, leading to different amounts of melanin and thus different eye colors.
Disassortative mating refers to the preference for individuals with different traits in a mate, which is not what's happening with HERC2 and OCA2. These genes are involved in the biological process of pigmentation, not mate selection.
For a more helpful explanation to your audience, you could say: "While HERC2 and OCA2 are both involved in eye color, they don't determine who we mate with. They are genes that work together to produce the different shades of brown, blue, or green we see in our eyes".
AI Overview
Traditional PFC creativity focuses on the ability to generate novel and useful ideas, while paradoxical PFC creativity involves embracing contradictions and inconsistencies to spark creative insights. Traditional creativity emphasizes originality and imagination, whereas paradoxical creativity acknowledges the potential benefits of incorporating seeming paradoxes and tensions into the creative process.
Traditional PFC Creativity:
Definition:
The ability to produce or develop original work, theories, techniques, or thoughts.
Key Characteristics:
Originality, imagination, expressiveness, and a focus on producing something new and valuable.
Examples:
Developing a new scientific theory, writing a novel, designing a new product, or creating a unique piece of art.
Brain Regions:
While not definitively mapped, studies suggest that the right frontal pole and other prefrontal subregions are involved in creativity tasks.
Paradoxical PFC Creativity:
Definition:
The ability to embrace and leverage contradictions and inconsistencies in order to generate creative solutions.
Key Characteristics:
Recognizing and accepting paradoxes, integrating opposing ideas, and finding creative ways to resolve or reconcile conflicting demands.
Examples:
Developing a business strategy that simultaneously focuses on both cost reduction and innovation, or designing a product that is both user-friendly and technologically advanced.
Brain Regions:
Studies suggest that paradoxical thinking can activate the prefrontal cortex and enhance connections between the default mode network (DMN) and executive control network, allowing for the integration of seemingly conflicting information.
Key Differences:
Approach to Contradictions:
Traditional creativity often aims to resolve contradictions, while paradoxical creativity embraces them as a source of inspiration.
Focus:
Traditional creativity focuses on generating something entirely new, while paradoxical creativity focuses on finding innovative solutions within existing contradictions.
Potential Benefits:
Traditional creativity can lead to breakthroughs and advancements, while paradoxical creativity can lead to more nuanced and adaptable solutions.
In essence, traditional PFC creativity is about creating something new, while paradoxical PFC creativity is about creating something new from the old, or more accurately, from the seemingly incompatible.
Concepts from cognitive neuroscience strongly suggest that the prefrontal cortex (PFC)
plays a crucial role in the cognitive functions necessary for creative thinking. Functional
imaging studies have repeatedly demonstrated the involvement of PFC in creativity
tasks. Patient studies have demonstrated that frontal damage due to focal lesions or
neurodegenerative diseases are associated with impairments in various creativity tasks.
However, against all odds, a series of clinical observations has reported the facilitation
of artistic production in patients with neurodegenerative diseases affecting PFC, such as
frontotemporal dementia (FTD). An exacerbation of creativity in frontal diseases would
challenge neuroimaging findings in controls and patients, as well as the theoretical role
of prefrontal functions in creativity processes. To explore this paradox, we reported the
history of a FTD patient who exhibited the emergence of visual artistic productions during
the course of the disease. The patient produced a large amount of drawings, which have
been evaluated by a group of professional artists who were blind to the diagnosis. We
also reviewed the published clinical cases reporting a change in the artistic abilities in
patients with neurological diseases. We attempted to reconcile these clinical observations
to previous experimental findings by addressing several questions raised by our review.
For instance, to what extent can the cognitive, conative, and affective changes following
frontal damage explain changes in artistic abilities? Does artistic exacerbation truly reflect
increased creative capacities? These considerations could help to clarify the place of
creativity—as it has been defined and explored by cognitive neuroscience—in artistic
creation and may provide leads for future lesion studies.
Damage to the PFC may alter the intentional appropriateness and originality of patient productions by altering planning, fluency, mental flexibility, rule-based thinking, or abstraction. However, clinical observations of frontal damage patients suggest that some symptoms associated with frontal damage provoke cognitive, conative, and behavioral changes, including social disinhibition, compulsive behaviors, emotional distortions, and the relaxing of cognitive constraints, which can motivate and favor artistic productions. However, artistic production is not synonymous with creativity, because creativity refers to aspects such as emotional expression, evocative impact, aesthetic, and technical abilities, which are present in art but not necessarily in other domains of creativity. Art is thus difficult to capture using theory-based creativity tasks, and to our knowledge, patients with facilitation in the artistic domain have not been tested experimentally with such tasks. Therefore, whether these rare frontal patients increase their real creative capacity does not have a yes or no answer.
Where Does The DHT Hair Loss Myth Come From?
The belief that DHT causes hair loss, although untrue, is the main side effect associated with this testosterone medication. So where did these myths come from?
DHT is a hormone produced from testosterone, which is closely linked to male characteristics, including hair growth. Studies have shown people with higher DHT levels experience hair thinning or balding and media portrayals have reinforced this misconception.
The main thing you need to understand is this – several factors behind DHT hair loss have been overlooked. New evidence suggests a more complicated relationship, but the idea has stuck around for a long time.
AI Overview
The misconception is that taking testosterone medication directly causes hair loss simply by increasing DHT levels; while increased DHT can contribute to hair loss in genetically predisposed individuals, the primary "side effect" often experienced is the anxiety about potential hair loss due to this association, not actual significant hair loss from the medication itself.
AI Overview
The statement is referring to the misconception that taking testosterone medication can directly cause hair loss due to increased DHT levels, even though the real issue is a genetic predisposition to sensitivity to DHT, not the testosterone itself; meaning the "side effect" is the anxiety about hair loss, not actual hair loss from the medication itself.
AI Overview
Yes, disassortative mating in humans, particularly regarding the Major Histocompatibility Complex (MHC) genes, is thought to be beneficial for immune function. This type of mating, where individuals choose partners with dissimilar MHC genes, is believed to lead to offspring with a broader range of pathogen recognition capabilities, thus enhancing their immune response.
Here's why:
The MHC genes play a critical role in the immune system by coding for proteins that help the body recognize and respond to pathogens.
Individuals with diverse MHC genes (heterozygotes) tend to have a wider repertoire of pathogen recognition, potentially offering a survival advantage.
Disassortative Mating and MHC Diversity:
By choosing partners with different MHC genes, individuals increase the likelihood of their offspring inheriting a more diverse set of these genes, leading to a greater capacity to fight off a wider array of pathogens.
Disassortative mating can also help reduce the risk of inbreeding, which can lead to offspring with reduced immune function due to the expression of deleterious recessive alleles.
While the link between MHC and mate choice is well-established in various species, including humans, some studies have shown mixed results regarding preference for MHC dissimilarity in humans. However, the general consensus is that disassortative mating, particularly at the MHC, is an adaptive strategy that contributes to immune defense.
The MHC loci on chromosome 6 is a crucial predisposing factor for number of
auto immune diseases (Vasiliki, Vinod, et al., 2017).
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