Lecture 4- Genetics, Epigenetics, and Early Life Development

Question 1

Define Genome

Answer 1

1) The complete set of genetic material in organisms
2) all DNA sequences of an organism

Question 2

Describe the features of DNA

Answer 2

1) Double helix
2) bade of base pairs A-T, G-C
3) nucleotides are the basic units of the DNA

Question 3

Define gene

Answer 3

specific sequence of nucleotides that codes for a protein

Question 4

Why are proteins important?

Answer 4

essential for all biological functions like building cells or regulating chemical reactions

Question 5

What is dominant inheritance?

Answer 5

trait that observable in every generation

Question 6

What is recessive inheritance?

Answer 6

trait that disappear in one generation, only to reappear in a subsequent one

Question 7

How many chromosomes do humans have?

Answer 7

46
- autosomes- 22 pairs are same in both male and female
- sex chromosome differs

Question 8

Define genotype

Answer 8

part of the genetic makeup of an individual which determines their characteristics e.g. eye colour

Question 9

Define phenotype?

Answer 9

Set of observable characteristics of an individual resulting from the interaction of the genotype with the environment

Question 10

What is monozygotic twin?

Answer 10

share 100% of DNA

Question 11

What is a dizygotic twin?

Answer 11

share 50% of the gene

Question 12

Why do we study twins?

Answer 12

As they share the same environment, comparing their similarities helps separate genetic and environmental factors

Question 13

Define heritability

Answer 13

the proportion of phenotypic variation that can be explained by genetic variation

Question 14

What did Polderman et al (2015) find?

Answer 14

1) meta-analysis find a 49% heritability between twins

Question 15

What is Epigenetics?

Answer 15

• changes that do not alter the DNA sequence but affect how genes are expressed (environmental factors)
• influence of experience on gene expression

Question 16

What is genetic inheritance?

Answer 16

1) traits inherited through rare DNA mutation
2) selection is slow- takes many generations to adapt to environmental changes

Question 17

What is the difference in epigenetics compared to genetic inheritance?

Answer 17

1) changes do not alter the DNA sequence
2) changes influenced by environmental factors
- nutrition, stress, toxins
3) Faster adaptation

Question 18

What does epigenetic change include?

Answer 18

1) DNA methylation
2) Histone modification
3) both regulate gene expression without altering DNA sequence

Question 19

What is DNA methylation?

Answer 19

1) acts by turning genes off
2) methyl group can attach to DNA segments and decrease the access to these segments
3) Lead to long-term gene silencing

Question 20

What is developmental plasticity?

Answer 20

one genotype can give rise to a range of different physiological or morphological states in response to various environmental conditions during development

Question 21

What can modify an individuals Epigenome?

Answer 21

1) Nutritional status
2) Toxins
3) Stress

Question 22

Define Teratogens

Answer 22

Environmental agents that may cause developmental deviation in the foetus
- drugs
- medication
- Parental health/ emotional state

Question 23

What are the effects of teratogen?

Answer 23

abnormalities, mental impairments, emotional bond, and socioemotional impairments

Question 24

What are the effects of maternal smoking during pregnancy?

Answer 24

1) increased hyperactivity
2) conduct disorder
3) Asthma
4) changes in DNA methylation in the placenta, foetal cord and pulmonary function during childhood

Question 25

What are the effects of maternal alcohol consumption during pregnancy?

Answer 25

1) impaired growth
2) Stillbirth
3) Foetal alcohol spectrum disorder

Question 26

What are the effects of both smoking and alcohol during pregnancy?

Answer 26

1) changes to DNA methylation in the cord blood of an infant
2) epigenetic changes are critical between prenatal environment and substance abuse risk in adolescence