Genetics and Evolution

Question 1

What are 3 related problems?

Answer 1

The mind-body problem, the free will problem, the nature-nurture problem

Question 2

Behavioral Genetics

Answer 2

Empirical science of how genes and environments combine to generate behaviour

Question 3

Adoption Study

Answer 3

A behaviour genetic research method that involves comparison of adopted children to their adoptive and biological parents

Question 4

Twin Studies

Answer 4

A behaviour genetic research method that involves comparison of the similarity of identical (monozygotic; MZ) and fraternal (dizygotic; DZ) twins

Question 5

Quantitative Genetics

Answer 5

Scientific and mathematical methods for inferring genetic and environmental processes based on the degree of genetic and environmental similarity among organisms

Question 6

Heritability coefficient

Answer 6

An easily misinterpreted statistical construct that purports to measure the role of genetics in the explanation of differences among individuals

Question 7

Nature Vs. Nuture

Answer 7

• Everything has turned out to have some footing in genetics
• The more genetically related people are, the more similar they are for everything: height, weight, intelligence, personality, mental illness, etc.
• You can’t leave genes out of the equation, but no behavioral traits are completely inherited so you cannot leave environment out either

Question 8

How much of their genetic code do fraternal twins share?

Answer 8

50%

Question 9

Natural Selection

Answer 9

Differential reproductive success as a consequence of differences in heritable attributes

Question 10

Adaptations

Answer 10

Evolved solutions to problems that historically contributed to reproductive success

Question 11

First class: Survival Adaptations (for physical survival)

Answer 11

Mechanisms that helped our ancestors handle the “hostile forces of nature”
Example: To survive very hot temperatures we developed sweat glands to cool ourselves.

Question 12

Second class: Sexual Selection Theory (for reproductive survival)

Answer 12

• Proposed by Charles Darwin
• Noticed that there were many traits and behaviors that could not be described by survival selection (example: peacocks colorful feathers)
• The evolution of characteristics, not because of survival advantage, but because of mating advantage
  § Occurs through two processes:
  □ Intrasexual competition: When members of one sex compete against each other, and the winner gets to mate with a member of the opposite sex (Example: Male antlers).
  Intersexual competition: A process of sexual selection by which evolution (change) occurs as a consequences of the mate preferences of one sex exerting selection pressure on members of the opposite sex

Question 13

Gene Selection Theory

Answer 13

• All evolutionary processes boil down to an organism’s genes
• Genes are basic “units of heredity”
• Information passed along in DNA that tells the cells and molecules how to “build” the organism and how that organism should behave
• Genes can boost their own replicative success in two basic ways
• Influence the odds for survival and reproduction of the organism they are in
• Genes can also influence the organism to help other organisms who are likely to contain those genes “genetic relatives” to survive and reproduce

Question 14

Psychological Adaptations

Answer 14

• Mechanisms of the mind that evolved to solve specific problems of survival or reproduction; conceptualized as information processing devices
• These kinds of adaptations, are contrast to physiological adaptations

Question 15

Error Management Theory

Answer 15

• Error management theory deals with the evolution of how we think, make decisions, and evaluate uncertain situations
  
  • “Cost asymmetries”
  • EMT example is visual descent illusion, and auditory looming bias (People overestimate how close objects are when the sound is moving toward them compared to when it is moving away from them
  • EMT has been used to predict adaptive biases in the domain of mating

Question 16

Eric comes into work one day to find that a new woman has been hired as the front-desk receptionist. She smiles at him and Eric wonders if she is flirting. The fact is she was simply being friendly and professional. Eric has fallen victim to the _______ bias.

Answer 16

Sexual Over perception

Question 17

__________ is the process of sexual selection by which members of one sex compete with each other, with the victors gaining enhanced mating access to members of the opposite sex.

Answer 17

Intrasexual competition.

Question 18

________ theory deals with the evolution of cognitive biases that lead to judgements and decisions we make in situations of uncertainty.

Answer 18

Error Management

Question 19

Epigenetics

Answer 19

Epigenetics: The study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence. Epigenetic marks include covalent DNA modifications and posttranslational histone modifications

Question 20

Phenotype

Answer 20

Phenotype: The pattern of expression of the genotype or the magnitude or extent to which it is observably expressed - an observable characteristic or trait of an organism, such as its morphology, development, biochemical or physiological properties, or behavior.

Question 21

Epigenome

Answer 21

Epigenome: The genome-wide distribution of epigenetic marks; is highly dynamic, differing among cell types, tissues, and brain regions

Question 22

Describe the dynamic epigenome

Answer 22

• Almost all the cells in our body are genetically identical, yet our body generates many different cell types, organized into different tissues and organs, and expressed in different proteins
• Within each type of mammalian cell, about 2 meters of genomic DNA is divided into nuclear chromosomes. Yet the nucleus of a human cell, which contains the chromosomes, is only about 2 μm in diameter. To achieve this 1,000,000-fold compaction, DNA is wrapped around a group of 8 proteins called histones. This combination of DNA and histone proteins forms a special structure called a “nucleosome,” the basic unit of chromatin, which represents a structural solution for maintaining and accessing the tightly compacted genome.

Question 23

Describe DNA Modification (Primary Epigenetic Mark)

Answer 23

• DNA methylation is the best understood epigenetic modification influencing gene expression. It occurs primarily at cytosine residues in the context of cytosines that are followed by guanines to form a 5-methylcytosine in a cell-specific pattern
  
  • The enzymes that perform this are called DNA methyltransferases which catalyze the transfer of a methyl group to the cytosine.
  • This may broadly impact human brain development, and age-related mis regulation of DNA methylation is associated with the molecular pathogenesis of neurodevelopmental disorders

Question 24

Describe Histone Modification and Histone Code

Answer 24

• Acetylation of histone tails is mediated by the opposing enzymatic activities of histone acetyl transferases and histone deacetylases.
• The removal of the acetyl group by HDAC enzymes is generally associated with DNA methylation, gene slicing, and decreased gene expression.
• Research shows that modifications and DNA methylation of certain genes mediates the long term behavioral effects of care experienced during infancy.

Question 25

Describe Early Childhood Development

Answer 25

• The development of an individual is an active process of adaptation that occurs within a social and economic context
• The process previews the offspring with the ability to physiologically adjust gene expression profiles contributing the organization and function of neural circuits and molecular pathways that support lots of traits

Question 26

Describe the Effect of Parent Investment and Stress Responses on Offspring

Answer 26

• The effects of maternal care on stress hormone responses and behavior in the offspring can be eliminated in adulthood by pharmacological treatment or dietary amino acid supplication treatments that influence histone acetylation, DNA methylation, and expression of the glucocorticoid receptor gene
• Post-mortem brain tissue from healthy human subjects shows that the human equivalent of the glucocorticoid receptor gene promoter is also unique to the individual

Question 27

How does the a child’s nutrition affect the epigenome?

Answer 27

• Nutrients can reverse or change DNA methylation and histone modifications, thereby modifying the expression of critical genes associated with physiologic and pathologic processes
  Nutrients can influence the epigenome either by directly inhibiting enzymes that catalyze DNA methylation or histone modifications, or by altering the ability of substrates necessary for those enzymatic reactions