Ch. 2 Flashcards
threadlike structure made up of deoxyribonucleic acid, or DNA
Chromosome
a complex molecule with a double helix shape; contains genetic information
DNA
units of hereditary information composed of DNA. Genes help cells to reproduce themselves and help manufacture the proteins that maintain life.
Genes
Cellular reproduction in which the cell’s nucleus duplicates itself with two new cells being formed, each containing the same DNA as the parent cell, arranged in the same 23 pairs of chromosomes.
Mitosis
A specialized form of cell division that occurs to form eggs and sperm (also known as gametes)
Meosis
a mature haploid male or female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote.
Gamete
a stage in reproduction when an egg and sperm fuse to create a single cell, called a zygote.
Fertilization
a single cell formed through fertilization
Zygote
identical twins - share 100% of genes
Monozygotic
fraternal twins - only share 50% of genes
Dizygotic
a person’s genetic heritage; the actual genetic material
Genotype
the way an individual’s genotype is expressed in observed and measurable characteristics
Phenotype
expressed characteristics (or phenotype) of an organism depend both on genetic characteristics (or genotype) and the environment
Reaction range
what is the likelihood of something being found when comparing groups
If Twin A has certain characteristics, what is the chance twin B will have the same?
Expressed as a percentage
Concordance
how much shared genetics between the individuals you are comparing
100% = identical twins
50% shared genotype = fraternal twins
Kinship
the field that seeks to discover the influence of heredity and environment on individual differences in human traits and development.
Behavior genetics
Describe the three types of “Family Studies” discussed in lecture (“Twin studies”, “Adoption studies”, “Combine twin and adoption studies”); know the questions posed by each type of study.
“Twin Studies”
“Are pairs of identical twins (MZ) who are raised together (same environment) more alike than pairs of fraternal twins (DZ) who are raised together?”
Can correlate evocative genotype-environment
“Adoption Studies”
“Are adopted children more like their biological parents who genes they share? Or are they more like their adopted parents whose environment they are sharing?”
Often times adoption agencies will try for health reasons:
Match up a potential adoptee that shares their ethnic background, religion, culture, etc. (affects nature if said yes to adopted children more like biological parents)
“Combine Twin & Adoption Studies” (note: this type of study is not common)
Combine Twin Question A: “Would identical twins who are raised apart, be more like each other than fraternal twins that are raised apart?”
Question B: “Would identical twins who are raised together, be more alike than identical twins who are raised apart?”
Behavioral geneticists point out:
that when identical twins show differences, it is believed to be due to the environment.
We tend to exaggerate how different the environments may be for separated identical twins.
“Same life cohort” - even when you separate twins, they are still born and living through the same historical period.
Identical twins - genetically predisposed to be similar - focus and select certain things in their environment
If identical twins are genetically predisposed to select or attend similar parts of the environment and if their environments are not different to begin with (same life cohort) then we should not be surprised if these identical twins are similar. ( when separated at birth)
Know Thomas and Chess views of newborn/infant temperament. Describe “easy”, “difficult”, and “slow-to-warm-up” infant classifications and the role of certain temperament dimensions on such classifications- i.e., “rhythmicity”, “mood quality”, and “adaptability” (discussed in class lecture)
“Temperament characteristics” observed by Alexander Thomas & Stella Chess
Rhythmicity - regularity of body functions (eating, sleeping, etc)
Adaptability - ease of adjustment to new situations/people
Intensity of reaction
Threshold of responsiveness (sensitivity to stimulation)
Mood quality - relative time spent in a “pleasant” - “unpleasant” state
Distractibility
Persistence of attention
Use these 3 measures to rank babies- “easy”, “difficult” , and “slow-to-warm-up”
Monozygotic twins are more alike than dizygotic twins in many qualities of temperament - (bias towards biological) refers to someone’s “consistent” style of responding to a broad range of environmental events.
- Activity level
- Irritability
- Sociability - including general positive or negative response to strangers (e.g. smiling, playfulness, expression of fear)
- You are who you are where you are
emphasizes that development reflects an ongoing, bidirectional interchange between heredity and environment.
-researchers study how the same genotype can lead to very different phenotypes.
Ex: a baby inherits genes from both parents at conception. During prenatal development, toxins, nutrition, and stress can influence some genes to stop functioning while others because more active or less active.
-During infancy, environmental experiences such as toxins, nutrition, stress, learning and encouragement continue to modify the genetic activity and the activity of the nervous system that directly underlie behavior.
- heredity ←> environment
Epigenetic view
the interaction of a specific measured variation in the DNA and a specific measured aspect of the environment.
- the epigenetic mechanisms involve the actual molecular modification of the DNA strand as a result of environmental inputs in ways that alter gene functioning
- heredity → environment
Gene x environment (G x E) interaction
children inherit genetic tendencies from their parents, and parents also provide an environment that matches their own genetic tendencies
ex: musically inclined parents usually have musically inclined children and they are likely an environment rich in music for their children
passive genotype-environment correlations
the child’s genetic tendencies elicit stimulation from the environment that supports a particular trait. Thus genes evoke environmental support
ex: a happy, outgoing child elicits smiles and friendly responses from others
Evocative genotype-environment correlations
Children actively seek out “niches” in their environment that reflect their own interests and talents and are thus in accord with their genotype.
Ex: Libraries, sports fields, and a store with musical instruments are examples of ___ children might seek out if they have intellectual interests in books, talent in sports, or musical talents, respectively.
Active (niche-picking) genotype-environment correlations
