Type 2 Diabetes and Genetic Concepts

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Questions and Answers

What is the primary reason cited for the high maternal mortality rate during childbirth in women?

Underdeveloped medical technology

Increased size of newborn skulls

Obstetrical dilemma (correct)

Narrower pelvis from bipedalism

How did bipedalism affect the shape of the pelvis in females?

It caused the pelvis to become narrower. (correct)

It had no effect on the pelvis.

It made the pelvis more circular.

It made the pelvis wider for easier childbirth.

What is encephalization in the context of childbirth?

Development of larger pelvises in females

Reduction in brain size of newborns

Increase in brain size relative to body size (correct)

A decrease in maternal health during gestation

Why do human mothers generally seek assistance during childbirth unlike great apes?

Human babies are born more undeveloped. Signup and view all the answers

What term describes species whose offspring are more helpless at birth?

Altricial Signup and view all the answers

What role does stabilizing selection play in the evolution of the female pelvis?

It maintains a balance between walking ability and brain size. Signup and view all the answers

Why has the evolution of a wider pelvis not been prioritized in females despite the challenges of childbirth?

It would compromise their ability to walk. Signup and view all the answers

What major problem arises during childbirth due to the obstetrical dilemma?

Babies having larger heads Signup and view all the answers

How does physical activity (PA) influence somatic repair in the body?

By stimulating production of antioxidants Signup and view all the answers

What is the approximate reduction in relative risk of all-cause mortality for a sedentary person who engages in 150 minutes of moderate exercise per week?

50% Signup and view all the answers

What effect does 3 to 4 hours of moderate exercise per week have on the risk of breast cancer in women?

Reduces the risk by 30-40% Signup and view all the answers

In what way does physical activity support the immune system?

By aiding in the attack of mutant cells Signup and view all the answers

What does the term 'spandrel' refer to in the context of adaptations?

A byproduct of other adaptations and traits Signup and view all the answers

What is the term used to describe the wear and tear on the body due to chronic stress?

Allostatic load Signup and view all the answers

Which of the following symptoms is NOT commonly associated with Irritable Bowel Syndrome (IBS)?

Weight gain Signup and view all the answers

Which dietary components have been linked to contributing to IBS symptoms?

Short-chain carbohydrates Signup and view all the answers

What factor is NOT mentioned as influencing the composition of the microbiome?

Personality traits Signup and view all the answers

How does the contemporary U.S microbiome differ from that of our evolutionary past?

It is more likely to be in a state of dysbiosis. Signup and view all the answers

What role do gut microbes play in human evolution?

They promote energy storage. Signup and view all the answers

Which group of microbial organisms specifically resides in the human body?

Microbiota Signup and view all the answers

What has been suggested as a potential cause of IBS?

Stress Signup and view all the answers

Which factor is NOT considered to shape variations in microbiomes?

Socioeconomic status Signup and view all the answers

What does the Energetics of Gestation and Growth Hypothesis (EGG Hypothesis) suggest regarding pregnancy?

Pregnancy ends when the fetus's energy needs exceed the mother's ability to support them. Signup and view all the answers

Which of the following is NOT a component of innate immunity?

T lymphocytes Signup and view all the answers

Which statement describes the nature of inflammation in the immune system?

Inflammation is a non-specific, quick response. Signup and view all the answers

What is a defining feature of adaptive immunity?

It is characterized by specificity, diversity, and memory. Signup and view all the answers

According to the hygiene hypothesis, which factor inhibits the immune system from learning about pathogenic responses?

A decrease in interactions with parasites due to improved hygiene. Signup and view all the answers

Which of the following correctly defines an antigen?

A substance that elicits a specific immune response. Signup and view all the answers

How do B lymphocytes contribute to adaptive immunity?

They produce antibodies against specific antigens. Signup and view all the answers

Innate immunity evolved before which other type of immunity?

Adaptive immunity Signup and view all the answers

What is the primary role of apoptosis in the context of cancer?

To facilitate programmed cell death Signup and view all the answers

Which of the following statements about the risks associated with obesity and cancer is TRUE?

Obesity is linked to a higher risk of breast, prostate, colon, and pancreatic cancer Signup and view all the answers

What does a clonal sweep indicate in the context of cancer evolution?

A dominance of a specific subclone over neighboring cells Signup and view all the answers

What health benefit is linked to increased physical activity in middle-aged humans according to the active grandparent hypothesis?

Improved overall health and extended lifespan Signup and view all the answers

Which hypothesis explains the co-evolution of factors such as extreme brain size and prolonged childhood in humans?

Embodied capital hypothesis Signup and view all the answers

How does mitochondrial metabolism produce reactive oxygen species (ROS)?

As a byproduct of metabolic processes Signup and view all the answers

What is the significance of the mismatch hypothesis in relation to cancer?

It highlights how modern lifestyles differ from ancestral patterns Signup and view all the answers

Which cancer types are associated with long-term positive energy balance?

Breast, prostate, colon, and pancreatic cancer Signup and view all the answers

What is a primary feature of Type 2 Diabetes?

Cells fail to respond to insulin effectively Signup and view all the answers

Which statement best describes the role of insulin in the body?

Insulin regulates glucose levels by enabling glucose to enter muscle and liver cells Signup and view all the answers

What does the Thrifty Genotype Hypothesis propose?

Certain genes may predispose individuals to diabetes due to starvation ancestry Signup and view all the answers

What is one critique of the Thrifty Genotype Hypothesis?

There is a lack of evidence for a selective sweep in populations Signup and view all the answers

What is a characteristic of the Thrifty Phenotype Hypothesis?

It asserts that nutrient scarcity in early life affects adult metabolism Signup and view all the answers

What factor is primarily influenced by the Respiratory Quotient (RQ)?

The macronutrient being metabolized Signup and view all the answers

What does the founder effect describe in terms of genetic variation?

Reduced genetic diversity due to a small group separating from a larger population Signup and view all the answers

How does the HPA axis primarily respond to stress?

It manages the release of glucocorticoids like cortisol Signup and view all the answers

What is one proposed evolutionary hypothesis explaining the negative health effects of stress?

Energy consumption for stress hinders other bodily functions Signup and view all the answers

What physiological response does the sympathetic nervous system primarily govern?

Fight or flight responses Signup and view all the answers

Which factor can lead to growth stunting in children?

Undernutrition during gestation and infancy Signup and view all the answers

What effect does cortisol have on the body during stress?

Regulates various body systems under stress Signup and view all the answers

Which characteristic is associated with the critical period in child development?

Development is highly sensitive to environmental changes Signup and view all the answers

How does the Predictive Adaptive Response Hypothesis explain development?

Children prepare their metabolism for adult environments based on early cues Signup and view all the answers

Which statement correctly describes leptin's function in the body?

Leptin signals the brain about energy storage and satiety Signup and view all the answers

Study Notes

Type 2 Diabetes

Caused by cells not responding to insulin
Dysfunction of cells prevents glucose from entering cells
Pancreas produces insulin which unlocks cells, enabling glucose storage
Insulin regulates glucose levels in the body

Thrifty Genotype Hypothesis

Proposed by Neil in 1962
Suggests a genetic predisposition to Type 2 diabetes related to periods of famine
Indigenous populations have a history of experiencing famines and periods of death.
Critique: many genes have small additive effects, long periods of famine are not hazardous or frequent in some populations.

Leptin

Hormone that regulates body weight by signaling the brain when a person is full

Genetic Drift

Random changes in allele frequencies within a population over time.
Often due to random chance, can lead to a reduction in allelic diversity.

Founder Effect

A specific type of genetic drift where a small population separates from a larger one and starts a new population with a smaller subset of the original diversity.

Poverty
Lack of access to health options for food
Lack of access to irrigation and land

Thrifty Phenotype Hypothesis

Undernutrition during development (infancy, childhood, gestation) leads to metabolic changes in adulthood.
Body adapts to scarcity, promoting fat storage for energy reserves
Lower growth rates and reduced metabolic rate.
Potential issues such as diabetes, hypertension and other cardiometabolic diseases

Growth Stunting

Height for age z-score (HAZ) <- 1.5 or 2
Standard deviation away from the average/mean height for a given age

Respiratory Quotient (RQ)

Measures the body's metabolic state (fat, carbohydrates, or protein) during fasting.
Calculated as VCO2/VO2 (VCO2=carbon dioxide production, VO2=oxygen consumption).
Close to 1.0 =carbohydrate metabolism
Close to 0.71 = fat metabolism

Evolutionary Constraint

Thrifty phenotype is constrained by evolutionary factors.
Beneficial during famine periods, but not for modern diets.
The pattern is not necessarily adaptive.

Immediate Adaptive Hypothesis

Short-term adaptation to cope with a challenging situation.
Body prioritizes immediate survival over long-term health consequences.
The adaptation comes at a cost to health, impacting fitness in the long term.

Predictive Adaptive Hypothesis

Longer-term adaptation to anticipate future environmental conditions, preparing for difficult periods.
The resulting phenotype promotes robustness through different cycles.
Early life conditions predict risks and create adaptations for later in life.

Immune Function

Fundamental system of the body for defense against pathogens

Stress

Body's response to environmental stressors, which could damage health

Autonomic Nervous System

Regulates unconscious body functions such as heart rate, blushing, digestion.
Composed of the sympathetic (fight-or-flight) and parasympathetic (rest-and-digest).

Hypothalamus-Pituitary-Adrenal (HPA) Axis

The body's response to physical or psychological stressors.
Hypothalamus releases CRH which stimulates the pituitary gland to release ACTH, leading to cortisol release by adrenal glands.

Cortisol

Regulates various bodily functions and is released in times of high stress

Energy Allocation Model

Stress allocates energy to stress response and away from other processes (immune function, growth, reproduction)

IBS (Irritable Bowel Syndrome)

Affects 10-15% of adults in the US
Associated with increased populations of specific gut bacteria (Veillonella and Lactobacillus).

Microbiota/Microbiome

Microbial organisms residing within the body.
Diversity in the microbiome varies by location within the body and over lifespan
Diet, antibiotics, and stress can influence the types and quantities of microbes.

Taxa/Taxon

Taxonomic group like species or genes.

Evolutionary Hypotheses of Gut Microbiome

Composition of the gut microbiome (current state) may differ from past evolutionary states.
Could be a byproduct of changing lifestyles and diets.

Obstetrical Dilemma

Adaptations for bipedalism (walking on two legs) cause changes to the pelvic region, influencing birth canal width and difficulty.
Head size and position of the birth canal can create a conflict between opposing selective pressures for birth and mobility

Encephalization

Increase in brain size relative to body size in humans.
Contributes to human cognitive capabilities.

Stabilizing Selection

Favors the middle range of traits for a trait (e.g., birth canal size).

Energetics of Gestation and Growth (EGG) Hypothesis

Fetal needs increasingly exceed the mother's ability to provide energy
This creates a pressure point between selection pressures favouring growth and maternal resources

Innate Immunity

Body's first line of defense response and non specific to pathogen

Adaptive Immunity

Specific Acquired responses and developed from prior exposure to pathogens

Hygiene Hypothesis

Early life exposure to pathogens is important for training the immune system.
Reduced exposure to pathogens, in modern environments, can lead to increased risk of autoimmune diseases.

Worms

Exposure to worms during childhood can influence the immune system to enhance tolerance or resistance to pathogens.

Schistomiasis

Caused by parasitic flatworms (schistosomes).
Can lead to numerous health issues.
Places with high parasite loads have lower rates of autoimmune diseases.

Reproductive Hormones

Progesterone, Estrogen and others play a vital role in the menstrual cycle, pregnancy, and other biological processes

Menstruation

Elimination of pathogens from the female reproductive tract.
Signal of fertility.
Possible evolutionary mechanism for removing non-viable embryos

Dose-dependent relationship between Physical Activity and Cancer

Moderate exercise (3-4 hours per week) is linked with lower risk of breast and colon cancer
Physical activity can improve the immune system's response to cancer cells.

Spandrel

A concept that a certain trait may arise as a consequence of adaptation for another trait, rather than evolving directly for its functions.

Grandmother Hypothesis

Proposes that grandmothers contribute to the survival of their grandchildren

Active Grandparent Hypothesis

Physical activity in middle age may have evolved to improve somatic maintenance

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Description

Explore the intricacies of Type 2 Diabetes, including its causes and the Thrifty Genotype Hypothesis. Understand the role of leptin in weight regulation, alongside genetic phenomena like genetic drift and the founder effect. Test your knowledge on these essential topics in biology and genetics.