Behaviour & Development terms

Question 1

DNA

Answer 1

Deoxyribonucleic acid

Molecules that carries the biochemical instructions involved in the formation and functioning of organisms.

Question 2

Gene

Answer 2

Section of chromosomes and portions of DNA

Basic unit of heredity

Question 3

Chromosome

Answer 3

thread-like molecules made up of DNA, containing many genes

Question 4

Genome

Answer 4

The complete sets of genes in any organism

Question 5

Genotype

Answer 5

the genetic material an individual inherits

Question 6

Phenotype

Answer 6

the observable expression of the genotype, including body characteristics and behaviour

Question 7

Environment

Answer 7

includes every aspect of the individual, and his or her surroundings, other than genes

Question 8

Karyotype

Answer 8

an individual’s complete set of chromosomes

Question 9

What is Mutation?

Answer 9

A change in a section of DNA. Caused by random or environmental factors (e.g., teratogens)

Question 10

Random assortment

Answer 10

The shuffling of the 23 pairs of chromosomes - chance determines which member of the pair goes into the new sperm and egg

-> makes 2^23 different combinations

Question 11

Crossing over

Answer 11

The process by which sections of DNA switch from one chromosome to another during meiosis, further increasing genetic variability

Question 12

Regulator genes

Answer 12

control the switching on and off of genes that underlie development across the lifespan

Question 13

Why are regulator genes needed?

Answer 13

• A given gene influences development and behavior only when it is turned on
• Important for healthy development

Question 14

Alleles

Answer 14

• Different forms of the same gene
• Therefore give rise to different phenotype
• 2 sub-types: dominant (expressed if present), recessive (not expressed if dominant allele is present)

Question 15

Heterozygous

Answer 15

A person who inherits two different alleles for a
trait

Question 16

Homozygous

Answer 16

A person who inherits two of the same allele for a
trait

Question 17

Mendelian inheritance patterns

Answer 17

Basically for heterozygous parents (coded as Bb), offsprings can be:
1 BB - homozygous dominant
2 Bb - heterozygous
1 bb - homozygous recessive

-> limitation of mendelian inheritance pattern: only account for single gene features (hair colour, eye colour)

Question 18

What is meant by the “male disadvantage”?

Answer 18

Individuals with only one x-chromosome (e.g. male XY) are more likely to suffer a variety of inherited disorders caused by recessive alleles on the X chromosome (e.g., color blindness)

Reason:
- Y chromosome has only about a third of X chromosome’s genes
- Many alleles on the X chromosome do not have a corresponding allele on the Y chromosome that could suppress the action.

Question 19

Types of genetics-origin diseases and disorders in humans + examples?

Answer 19

over 5000 are known to have genetics-origin

• recessive gene: sickle-cell anaemia, PKU, cystic fibrosis
• single dominant gene: Huntington’s disease
• sex-linked: hemophilia, Fragile-X syndrome
• error in meiosis (zygote with different number of chromosome components): Down syndrome - trisomy 21

Question 20

Polygenetic inheritance

Answer 20

• Inherited characteristics are governed by more than one gene (e.g. height, intelligence)
• Polygenetic inheritance applies to most traits and behaviors of interest to behavioral scientists

Question 21

Norm of Reaction (Dobzhansky, 1955)

Answer 21

all possible phenotypic outcomes, that could theoretically result from a given genotype in relation to its environment.

Question 22

Example of Norm of reaction (PKU)

Answer 22

• Children with phenylketonuria (PKU)— a disorder that is related to a defective gene on chromosome 12—are unable to metabolize phenylalanine (e.g. food sweetener)
• With early diagnosis and a properly restricted diet -> cognitive impairment can be avoided

Question 23

Example of Norm of reaction (MAOA)

Answer 23

• Men who have experience severe malnutrition (environment) are more likely to engage in antisocial behavior
• INCREASE effect with inactive MAOA gene

Question 24

What is study in Behaviour Genetics?

Answer 24

• How variation in behaviour and development results from the combination of genetic and environmental factors (mainly in family-study)
• Correlations between the measure of the trait in individuals with different relationships are examined to see whether larger effect for environmental-basis (share environment) or genetic-basis (twins)

Question 25

What are two types of Family Studies?

Answer 25

1. Twin-Study Designs:
   correlation for traits of interest in monozygotic twins vs dizygotic twins
2. Adoption Studies:
   whether adopted children are more like their biological or their adopted relatives

Question 26

Heritability

Answer 26

measure (statistical estimate) of how well differences in people’s genes account for differences in their traits

Question 27

What are limitations of heritability?

Answer 27

• They apply only to populations, not to individuals
• They apply only to a particular group living at a particular time
• They can differ markedly for groups of people who grow up in very different environments

Question 28

Environmental Effects on phenotype?

Answer 28

• Shared-environment (growing up together): Little effect of shared environment on some aspects of development
• Non-shared environment effects: include experiences unique to the individual -> increase the differences among family members

Question 29

Findings from Minnesota Study of Twins Reared
Apart?

Answer 29

Located and studied twin siblings who have not met since they were infants.

Longitudinal study

Results:
– Similarities in traits like IQ, reaction to
stress, and traditionalism, personality, hobbies, professions…

Conclusions:
– These similarities may be influenced by selective placement and similarities in fostering environments as well as by genetic factors