Nature vs Nurture and Behavioural Genetics Flashcards
What is the name of the molecule that carries the biochemical instructions involved in the formation and functioning of an organism?
DNA
What term is used to describe the sections of chromosomes and portions of DNA (basic unit of heredity in all living things)
Genes
What is the name of – thread-like molecules made up of DNA and containing many genes?
Chromosomes
What is the term used to describe the complete set of genes in any organism?
Genome
What is the term used to describe the genetic material that an individual inherits from their parents?
Genotype
What is the term used to describe the observable expression of the genotype, including body characteristics and behaviour?
Simply = How do your observable characteristics and behaviour show that you have a certain type of inherited genes?
Phenotype
What is the term used to describe every aspect of an individual (i.e. their surroundings) other than their inherited genes?
Simply = Anything outside of genetic control
Environment
Explain what it means by …
Parents Genotype affects Child’s Genotype
Parents’ genes are passed onto their child’s genes
Explain what it means by …
Child’s Genotype affects Child’s Phenotype
A child’s genes affect the way they behave/affects their observable behaviour
Explain what it means by …
Child’s environment affects Child’s Genotype
A child’s environment in which they grow up in affects the way they behave/ their observable behaviour
Explain what it means by …
Child’s Phenotype affects Child’s Environment
The way a child behaves/ the observable behaviour of the child can influence the environment around them (i.e. their peers)
Explain what it means by …
Child’s Environment affects Child’s Phenotype
A child’s environment in which they grow up in can alter the ways in which their genes are expressed as phenotypes
How is genetic material from the parents passed onto the child?
Genetic material is passed on as chromosomes (long, threadlike molecules made up of DNA)
An individual’s complete set of chromosomes is known as a….?
Karyotype
What causes/contributes to genetic diversity? List 3 things
1) Genetic mutation
2) Random assortment
3) Crossing over
What is the term used to describe the change in a section of DNA which can be caused by random or environmental factors (e.g., teratogens)?
Mutation
What is the term used to describe the shuffling of the 23 pairs of chromosomes in the sperm and egg?
Random assortment
What happens when chromosomes go through random assortment?
- Increases genetic diversity
- Chance determines which member of the pair goes into the new sperm and egg
- Makes 8.4 million combinations of chromosomes in each gamete
What term is used to describe the process by which sections of DNA switch from one chromosome to another during meiosis, further increasing genetic variability?
Simply = When gametes divide, 2 members of a pair of chromosomes sometimes swap sections of DNA
Crossing over
What term is used to describe the process by which sections of DNA switch from one chromosome to another during meiosis, further increasing genetic variability?
Simply = When gametes divide, 2 members of a pair of chromosomes sometimes swap sections of DNA
Crossing over
What is the term used to describe certain genes that can repeatedly switch other genes on and off in different patterns to help with healthy development?
Regulator genes
A given gene influences development and
behaviour only when it is …
Turned on
What term is used to describe when genes have two or more different forms?
Alleles
What is the term used to describe the form of the gene that is expressed if present?
Dominant allele
What is the term used to describe the form of the gene that is not expressed if a dominant allele is present?
Recessive allele
What is the term used to describe a person who inherits two of the same alleles for a trait?
Homozygous
What is the term used to describe a person who inherits two different alleles for a trait?
Heterozygous
B = Dominant allele for Brown eyes
b = Recessive allele for blue eyes
A father has = Bb
A mother has = Bb
What is the probability that 4 of their children will have BB?
1/4
B = Dominant allele for Brown eyes
b = Recessive allele for blue eyes
A father has = Bb
A mother has = Bb
What is the probability that 4 of their children will have bb?
1/4
B = Dominant allele for Brown eyes
b = Recessive allele for blue eyes
A father has = Bb
A mother has = Bb
What is the probability that 4 of their children will have Bb?
2/4
B = Dominant allele for Brown eyes
b = Recessive allele for blue eyes
A father has = Bb
A mother has = Bb
What is the probability that 4 of their children will have Brown eyes?
3/4
Because the chances of BB = 1/4
and the chances of Bb = 2/4
What is the male advantage?
Where males are more prone to illnesses and inherited disorders (i.e. colour blindness)
Why are males more prone to suffer from inherited disorders (i.e. colour blindness)?
1) The Y chromosome is a lot smaller than the X chromosome
(has only about 1/3 as many genes on it as the X chromosome)
2) Many alleles on the X chromosome do not have a corresponding allele/ matching allele on the Y chromosome that could suppress the action
(because there are not enough genes in the Y to match with genes on the X)
3) Males inherit dominant alleles from the mother but recessive alleles from the father (XY) compared to females who inherit dominant alleles from mother and father (XX)
4) Therefore, individuals with only one dominant allele/ X chromosome are more likely to suffer a variety of inherited disorders caused by recessive alleles on the X chromosome
What are the well-known illnesses caused by recessive genes?
- PKU (cannot eat amino acids, causes impairment to the brain development)
- Sickle-cell anaemia
- Cystic fibrosis
What is the well-known illness caused by single dominant genes?
Huntington’s disease (dormant disease; does not show till mid-late adulthood)
What are the well-known illnesses caused by sex-linked inheritance?
- Fragile-X syndrome
- Hemophilia
What is the well-known illness caused by errors in meiosis (when the zygote is supposed to double in cells but instead, the chromosomes are more than normal)?
Down-syndrome
What is the term used to describe a debilitating blood disorder when both recessive sickle-cell anemia alleles are present?
Simply = When you have 2 recessive alleles for sickle-cell anemia present which causes a blood disorder
Deleterious effects
How can having alleles which have the genetic material for sickle-cell anemia protect you against malaria?
This only works if you have 1 dominant allele and 1 recessive allele for sickle-cell anemia
If both of your alleles ar recessive, you’ll suffer from blood disorders/sickle-cell anemia
The inheritance of a trait is governed by more than one gene(s).
What term is used to describe this?
Polygenetic inheritance
Who proposed the idea of the “Norm of Reaction”?
Dobzhansky
What did Dobzhansky discover in his experiment investigating the norm of reaction?
Even though plants of the same family had inherited the same genetic material (genotype), their observable behaviour/growth height or posture (phenotype) differed depending on what environment they were in
What do the results of Dobzhansky’s norm of reaction experiment suggest?
An individual’s observable behaviour (phenotype) could theoretically result from their inherited genes (genotype) in relation to their environment
What disorder involves a defective gene on
chromosome 12?
PKU or Phenylketonuria
What disorder involves the inability to metabolize phenylalanine (present in some foods such as sweeteners)?
PKU or Phenylketonuria
How can PKU be avoided early?
With early diagnosis and a properly restricted
diet
What is MAOA?
Genes associated with aggression
- High levels of MAOA = low aggression
- Low levels of MAOA = high aggression
Young men who had experienced severe
maltreatment were in general (………..) to engage in antisocial behavior than those who had experienced none, regardless of whether they had high or low levels of MAOA
a. More likely
b. Less likely
a. More likely
What does the family study investigate?
Aim to investigate any similarities or correlations between family members who share similar genetic material and share the same environment
What are the 2 types of family studies?
1) Twin-study design
2) Adoption studies
What type of family study is this?
The study aims to identify correlations for pairs of monozygotic twins on a trait of interest compared to those of dizygotic twins
Twin-study design
What type of family study is this?
Researchers examine whether adopted children are more like their biological or adopted relatives
Adoption studies
What did the Minnesota study of twins reared apart discover about monozygotic twins?
- The twin siblings have not met since they were infants
- They had the same/really similar IQs, reaction to stress and traditionalism
- They also had the same/really similar personality, hobbies and professions
- These similarities may be influenced by selective placement and similarities in fostering environments as well as genetic factors
What is the term used to describe how much of the variance seen in a population can be attributed to genetic variation instead of the environment?
Heritability
What are the disadvantages of heritability?
1) They apply only to populations, not to individuals
2) They apply only to a particular group living at a particular time
3) They can differ markedly for groups of people who grow up in very different environments
What does it mean by “the heritability of intelligence is considered to be 50%”?
Based on the population studied, 50% of the variation in IQ scores is due to genetic differences among members of the population
What is the most obvious source of shared environment?
Growing up together in the same family (siblings)
Why do siblings share surprisingly few similarities despite sharing the same environment at home?
Siblings may have quite different experiences within the same family and their experiences outside the family may diverge sharply
When considering the mechanisms that contribute to genetic diversity, “random assortment” refers to…
a. A change in a section of DNA, caused by random or environmental factors
b. The shuffling of the 23 pairs of chromosomes in the formation of sperm and egg
c. The process by which sections of DNA switch from one chromosome to another
d. None of the above
b. The shuffling of the 23 pairs of chromosomes in the formation of sperm and egg
Human cells have…
a. 46 chromosomes with the exception of egg and sperm cells.
b. the ability to create their own chromosomes from scratch.
c. the same number of chromosomes.
d. specialised chromosomes dependent on their function.
a. 46 chromosomes with the exception of egg and sperm cells
Behavioural genetics is the study of:
a. The genetic features of child development.
b. Parental influence on child behaviour.
c. The interaction of genetic and environmental factors.
d. How genes behave
c. The interaction of genetic and environmental factors.
Which of the following is NOT true?
a. The child’s phenotype affects their parents’ genotype
b. A child’s genotype affects their phenotype.
c. A child’s phenotype can be affected by their
M environment
d. The parents’ genotype determines the child’s genotype.
a. The child’s phenotype affects their parents’ genotype
