Midterm 1 - Unit 3, Genetics & Evolutionary Foundations of Behavior Flashcards

1
Q

Genome

A

The entire sequence of our DNA

  • complete set of genetic material; the “blueprint” for making & maintaining an organism
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2
Q

DNA

A

molecule that carries genetic information, organized and packaged within chromosomes

  • DNA is composed of hundreds of thousands of genes
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3
Q

Chromosomes

A

we carry 2 copies of the genome, which means that in most human body cells we have two pairs of 23 chromosomes, 46 total

  • molecule that carries genetic information, organized and packaged within chromosomes
  • rod-shaped structures that reside in a cell’s nucleus
  • A chromosome is composed of complex double strands of deoxyribonucleic acid (DNA)
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4
Q

Gene vs alleles

A

gene:
- segment of DNA that codes for a particular protein

Humans have 2 versions (alleles) of each gene, 1 from each parent
- A variant form of a gene; humans have two alleles per gene, one inherited from each parent.

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5
Q

dominant vs recessive allele

A

Alleles influence a phenotype by having a strong (dominant) or weak (recessive) influence.

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6
Q

genotype vs phenotype

A

genotype
- the genetic makeup of an organism composed of the organism’s compete set of genes

phenotype
- observable characteristics of an individual, produced by interaction of genotype and environment

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7
Q

homozygous vs heterozygous

A

homozygous: NN or nn, two dominant alleles, dominant shows, or two recessive alleles, recessive shows

heterozygous: one dominant and one recessive allele, dominant trait shows

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8
Q

how genes affect behavior

A
  • Genes do not directly code for a behavior or trait
  • Genes code for proteins, which contribute to physical structures & functions of the body, including the brain
  • Multiple genes are involved in giving rise to complex mental states, behaviors, & traits
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9
Q

Candidate gene study

A
  • compare individuals with the candidate gene with individuals without on a given trait or disorder
  • candidate gene study: a gene that is believed to be related to a particular trait, such as a disease or a physical attribute

limitations:
- Typically correlational in nature, Other factors, like other genes, cannot be ruled out

  • Underestimate biological complexity of multifaceted traits & behaviors
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10
Q

gene knockout vs gene knockdown

A

knockout:
- remove or deactivate gene

knockdown
- make gene less active

  • study: mice who don’t miss mom after knockdown of the gene u-opioid
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11
Q

genome-wide association studies

A
  • Instead of looking at single gene (or small set of genes), scan entire genome & look for associations with particular phenotype
  • limitations:
  • false positives
  • biological relevance often not clear
  • still correlational
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12
Q

diathesis-stress vs differential susceptibility model

A

diathesis-stress:
- some individuals have a predisposition (diathesis) that makes them more vulnerable to negative environmental influences (e.g., stress)

  • The diathesis-stress model states that people with a strong genetic predisposition for a given health condition will be more sensitive to having that condition triggered by a stressful environment.

differential susceptibility:
- some individuals are more sensitive to both negative and positive environmental influence

  • The differential sensitivities hypothesis suggests that some people have a genetic predisposition to be more strongly affected by their environment (both stressful and supportive conditions).
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13
Q

gene expression

A
  • Environmental factors affect which genes are turned “on” and “off
  • what influences it:
  • social environments
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14
Q

epigenetic change

A
  • type of change to structure of DNA that affects gene expression without altering the underlying DNA sequence
  • study: rat moms
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15
Q

study: rate moms, epigenetic change

A

Michael Meany and colleagues studied the effects of different parenting styles in rats. They found that pups of high licking and grooming (high LG) moms are less reactive to stress, both behaviorally and physiologically, due to increased receptors in the hippocampus, which helps regulate stress. Pups born to low LG moms but raised by high LG moms develop similar low stress reactivity and even become high LG moms themselves, showing that this behavior can be passed on across generations without genetic influence.

  • The point of Michael Meany’s study is to show how epigenetic changes can occur due to early-life experiences, like parenting. The differences in stress reactivity in rats are not caused by genes but by changes in how genes are expressed based on the mother’s behavior. High licking and grooming (high LG) causes changes in the brain that reduce stress, and these changes can be passed across generations, not through DNA but through behavior and environment. This demonstrates how epigenetics (environmental influences on gene expression) plays a key role in development.
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16
Q

behavioral genetics

A
  • study of strength of genetic influences on a behavior/trait
17
Q

heritability

A

how much of variation in phenotype across people can be attributed to variation in genotype

  • An indication of how much variation in phenotype across people is due to differences in genotype.

Heritability refers to how much of the variation in a trait (like height or intelligence) within a population is due to genetic differences. It’s expressed as a number between 0 and 1, or as a percentage.

A high heritability (close to 1) means that most of the differences in the trait are due to genes.
A low heritability (close to 0) means that most of the differences are due to environmental factors.

18
Q

twin studies on heritability

A
  • Can compare individuals who vary in degree of genetic relatedness on trait in question

limitations
- genetically related people also typically share similar environment

19
Q

artificial selection vs natural selection

A

artificial:
human-controlled selective breeding

natural:
process through which certain traits become more or less common in a population over time due to pressures of the environment

20
Q

evolution by natural selection, 3 componenents

A
  1. variation: Within a population of organisms, there is variation in traits or characteristics
  2. heredity: passing of traits from parents to their offspring
  3. differential fitness: some individuals are better at surviving and reproducing than others because of their traits
21
Q

functionalism

A
  • explains behavioral/mental/emotional/physiological processes by their utility
  • We can maybe look at certain trades and think about what purpose they have served in the past
22
Q

distal vs proximate

A

distal:
- what role did behavior play in survival and reproduction over evolutionary time?

  • Distal causes are the deeper, long-term reasons behind something. They explain why something happens in a broader, long-term context.

Example: You eat to survive and maintain your health—that’s a distal cause.

proximate:
- immediate triggers of the behavior

  • Proximate causes are the immediate reasons something happens. They explain how something works or occurs in the short term.

Example: You eat because you feel hungry—that’s a proximate cause.

23
Q

the need to belong

A

Throughout our evolutionary history, group living served as multi-purpose survival tool

  • Help hunting large game & foraging
  • Sharing food
  • Defensive vigilance and greater strength against predators and hostile outgroups
  • Help caring for offspring
  • Access to mates