Genetics and Epigenetics

Question 1

Mendel

Answer 1

Inheritance of traits
Pea’s study he observed that traits were passed down through dominant and recessive genes.

Question 2

Chromosomes

Answer 2

Single-cell protein that keeps DNA wrapped around histones.

Question 3

Study of Meiosis

Answer 3

Each cell contains 23 chromosomes, 22 equal in both genders.
The 23rd pair is the sex chromosome which dictates gender.
XX Female and XY male
Female egg produces X and Male sperm produces Y

Question 4

Genome

Answer 4

Organism complete set of DNA, including all its genes.
It contains information needed to build and maintain the organism.

Question 5

Heritability

Answer 5

Changes to the DNA sequence are passed along across generations

Question 6

Genotype

Answer 6

Determines potential characteristics
Homozygous: alleles are the same.
Heterozygous: alleles are different.

Question 7

Phenotype

Answer 7

Observable characteristics from the interaction of genotype and environment.
different alleles code for different phenotypes.

Question 8

Single Gene Disorders

Answer 8

Gene Mutations
Cystic fibrosis
Sickle cell disease

Question 9

Chromosomal disorders

Answer 9

abnormal number/structural arrangement of chromosomes
Down’s syndrome

Question 10

Complex/Multifactorial Disorders

Answer 10

Acquired mutations: cells don’t replicate as they should
Exogenous causes: environment, diet, substances, exercise, toxin exposure.

Question 11

Jean-Baptiste Lamark: Lamarckian theory

Answer 11

Acquired traits in response to the environment experienced over the lifetime will be transmitted to offspring.
Elongation of the neck in giraffes as trees grew taller.

Question 12

Epigenetics

Answer 12

The study of heritable changes caused by mechanisms other than changes in the underlying DNA sequence
The modification of DNA or alteration of associating proteins.
Soft inheritance
Reversible

Question 13

Behavioral epigenetics

Answer 13

Experiences within our environments can lead to long-term effects on the brain and subsequently behavior.
They can be passed across generations.

Question 14

Factors influencing epigenetic variation

Answer 14

Stress
Drug use
Social interactions
Pesticides
Smoking
Nutrition
Hormones

Question 15

Nurture

Answer 15

Experiences occurring during fetal development can have long-term effects.
The brain and body are developing rapidly, providing a window of opportunity for variation.
Post-natal maternal care gives rise to variation in brain and behavior. Can lead to postpartum depression

Question 16

Gene expression

Answer 16

DNA is wrapped around a cluster of proteins called histones.
Gene expression requires the unwrapping of DNA.

Question 17

DNA methylation

Answer 17

Repression of a gene expression when methyl chemical groups attach to DNA.

Question 18

Acetylation

Answer 18

Activates gene expression.

Question 19

Epigenetics and stress

Answer 19

Early life experiences and maternal care can influence the epigenetic marks on genes related to the stress response.
Rats born with gene-silencing epigenetic marks on receptors that handle stressful situations demonstrated removal of marks when the mother gave attention(licked or groomed) to the baby, returning gene function.

Question 20

Transgenerational impacts mediated by maternal care

Answer 20

Maternal experience, communal nursing, juvenile social experience, and stress in the first generation, induce epigenetic changes in itself and continuing generations.

Question 21

Human Prenatal Maternal Stress: Quebec Ice Storm

Answer 21

Women pregnant during disaster reporting objective hardship correlated with DNA methylation levels, genes related to immune function.
Subjective distress was uncorrelated.

Question 22

Dutch Famine Study

Answer 22

Prenatal exposure to famine during World War II demonstrated individuals in utero during the famine had a higher risk of certain health conditions, such as cardiovascular disease and obesity, later in life.

Question 23

Agouti yellow mouse

Answer 23

Prenatal exposure to vitamins, feed to the mother during pregnancy, were able to change the baby’s fur color without any gene mutation.

Question 24

Michael Meany: Postnatal stress

Answer 24

Rats raised by less-nurturing mothers have more methyl groups attached to the promoter region of the GC receptor gene, blocking access by transcription factors that turn the gene on. Resulting in the baby having fewer receptors produced not allowing shutdown of stress response easily.
Enzymes can reverse DNA methylation of the GC receptor gene, reversing the effects of a low-nurturing mother on the pup’s response to stress.

Question 25

Epigenetic modulation

Answer 25

Environmental exposures, stresses, diet, and lifestyle can all induce epigenetic changes that determine whether genes are turned on or off.

Question 26

Exercising: Rat Study

Answer 26

Exercise vs non-exercising rats are exposed to swim stress test.
Swimming behavior and dentate gyrus changes(hippocampus)

Question 27

Exercising: Human study

Answer 27

Exercise related to the demethylation of genes involved in energy metabolism

Question 28

Environmental experiences

Answer 28

Exposure to pesticides induces epigenetic variation in sperm leading to infertility.
These effects can persist over multiple generations.