W6: Genetics, epigenetics and development

Question 1

What is a genotype and what is the genotype contained in? (3)

Answer 1

Genotype is the genetic makeup of an individual

It is contained in the 23 pairs of chromosomes

The chromosomes are made up of pairs of alleles (e.g, genetic variants) provided by the parents

Question 2

Genotype ≠ you example

Answer 2

• Could inherit a gene for blue eyes but brown eyes because brown eyes is a dominant gene
• Carry gene for blue yes but don’t express it
• Have genetics that do not reflect who you are

Question 3

These epigenetic are: (2)

Answer 3

the influence of enviroment on gene expression

It alters the structure of DNA

Question 4

What is phenotype? - (2)

Answer 4

• ­Observable expression of genetics
• ­e.g., appearance, alcohol tolerance, metabolism

Question 5

Dominant alleles vs recessive traits (2)

Answer 5

Dominant alleles (e.g brown eyes) override recessive alleles (e.g blue eyes)

Recessive traits only appear when the recessive gene inherited from each parent (need to copies of the recessive allele)

Question 6

What are chromosomes? (2)

Answer 6

Thread-like structures inside the nucleus of cells

Chromosomes contains genes that are blueprints or instructions for building proteins

Question 7

Human cells usually contain ___ pairs of chromosomes

Answer 7

23 pairs of chromosomes

Question 8

22 pairs of chromosomes look

Answer 8

the same in males and females

Question 9

23rd pair of chromosomes differ

Answer 9

between males and females (X vs Y) - dicates their sex

Question 10

What is the 23rd pair of chromosomes in males? (sex chromosome)

Answer 10

XY (mismatched pair)

Question 11

What is sex chromosome in female? (23rd pair of chromosome)

Answer 11

XX - Matched pair

Question 12

What is epigenetics? (the study of…) -

Answer 12

The study of genetic changes caused by external mechanisms

Question 13

Epignetics

Genetic change (physiological adaptations) may be due to external mechanisms like… (3)

Answer 13

1. Nurtiton
2. Stress
3. Toxins

Question 14

These genetic changes (physiological adaptations) are not always (2)

Answer 14

adaptive changes

Epigenetics is often maladaptive

Question 15

Epigenetics are often involved in various disorders (6)

Answer 15

1. Alzheimer’s disease
2. Depression
3. Schizophrenia
4. Multiple sclerosis
5. Stress response
6. Cancer

Question 16

Methylation is the process which

Answer 16

Underlies epigenetics

Question 17

Methylation

What is a methyl group?

Answer 17

Molecules which contain 1 carbon atoms and 3 hydrogen atoms

Question 18

The methyl group attaches to the DNA segments which are located on the chromosome and serves as

Answer 18

Act as “switches” which activates (ON) or represses gene expression (OF)

Question 19

Early development - Epigenetics

Sources as to early development having long-impacts on health (3)

Answer 19

Fetal Origins Hypothesis

Developmental plasticity

Early birth weight

Intergenerational transmission

Question 20

Fetal Origins Hypothesis (3)

Answer 20

1. Role of nutrition and malnutrition in healthy fetal development
   
   1. Undernutrition during fetal development and infancy changes the body’s structure, physiology, and metabolism
   2. This may lead to coronary heart disease, stroke, cancer, diabetes and other issues later in adult life

Question 21

Developmental plasticity (2)

Answer 21

1. One genotype can lead to a range of physiological states in response to environments during development
2. Epigenetics!

Question 22

Birthweight is a predictor of heart disease (3)

Answer 22

Decreased chance for heart disease with increased birthweight

This is replicated in Europe, North America, and India

Assumed to be the result of slow fetal growth

Question 23

Intergenerational transmission (2)

Answer 23

Enduring epigenetic changes transmitted to offspring

Epigenetic changes occurring in the fetus can be passed on to later generations, affecting their descendants

Question 24

Intergenerational transmission

Examples

Answer 24

Not supposed to be smoking or drinking while pregnant

Question 25

Intergenerational transmission is that (2)

Answer 25

If you are smoking drinking or doing anything that has toxins that harm your body, this can be passed down to offspring E.g. nurtiton/stress you have experienced can be passed down

Question 26

Stress and intergenerational transmission (3)

Answer 26

Offspring of Holocaust survivors at greater risk for the development of PTSD, depression, and anxiety Women with PTSD from trauma during pregnancy give birth to at-risk offspring * Third trimester is more sensitive period for these effects

Question 27

The theory that underlies the epigenetic process

Answer 27

Theory of early epigenetic processes

Question 28

Theory of early epigenetic process Early experience of prolonged stress and early life adversities activate the stress hormone system

Answer 28

may program the system toward a lifelong alteration (genetic change) of the hormonal response to minor stressors - since assume stress would reoccur

Question 29

Theory of early epigenetic processes *Early experience of prolonged stress and early life adversities activate the stress hormone system and may program the system toward a lifelong alteration (genetic change) of the hormonal response to minor stressors* (2)

Answer 29

HPA axis is more sensitive to stressors because of epigenetic changes (methyl group attaching to DNA and changing how HPA axis functions on molecular level) Greater release of cortisol * Increased blood pressure * Likelhood of Heart disease and anxiety

Question 30

Early environmental experiences have a lasting impact on a child's later success in school and life generally Evidence

Answer 30

Vocabulary predictable at 18 months based on family education and income

Question 31

Adverse living circumstances impair development in first 24-36 months and the greater adversity, the greater the

Answer 31

odds of developmental delay

Question 32

*Risk factors for the development* Maltreated children who are exposed up to 6 adverse experiences face a 90-100% likelihood of having one or more

Answer 32

delays in their cognitive, language, or emotional development (Barth et al., 2008).

Question 33

*Risk factors for the development* Adults who recall having 7 or 8 adverse experiences in childhood are 3 times more likely to have

Answer 33

cardiovascular disease as an adult (Dong et al., 2004)

Question 34

Physiological adaptations in genes due to epigenetics can be due to (6)

Answer 34

1. Nutrition (Environment) - Fetal Origin Hypothesis 2. Birthweight predictor of heart disease 3. Toxins and intergenerational transmission - pregnancy 4. Stress and intergenerational transmission 5. Adverse living circumstances 6. Maltreated children (environment)