Chapter 2 - Behavioral Genetics

Question 1

Chromosomes

Answer 1

23 pairs of chromosomes
46 total chromosomes

(First 22 are autosomes, last one is our sex chromosome)

All children have an X chromosome
Sperm provides either an X or Y
Each chromosome consists of DNA

Question 2

Gene

Answer 2

Provides a specific def of biochemical instructions

The majority of genes are all the same in all people

Less than 1% of genes cause the differences we see in ppl

Question 3

Genotype

Answer 3

The complete set of genes making a persons hereditary (genetic make up)

Question 4

Phenotype

Answer 4

An individuals physical, behavioral, and psychological features

(created by both genetic features and environmental influences)

Environment can influence how certain genes are expressed

Question 5

Alleles

Answer 5

Different versions of a gene

Question 6

Homozygous

Answer 6

When alleles in a pair of chromosomes are the same (BB;bb)

Question 7

Heterozygous

Answer 7

When alleles in a pair of chromosomes are different (Bb)

Question 8

Dominant Allele (B)

Answer 8

Chemical instructions are typically followed

Question 9

Recessive Allele (b)

Answer 9

When paired with a dominant allele instructions ignored

Question 10

Incomplete dominance

Answer 10

Sometimes one allele does not dominate the other completely—the phenotype that results fall between dominant and recessive

(Example: dominant trait= curly hair + recessive trait= straight hair = incomplete dominance= wavy hair)

Question 11

Genetic disorder

Answer 11

Genetics can harm development in two ways:

Inherited disorders
Abnormal number of chromosomes

Question 12

Inherited disorders

Answer 12

A genetic problem caused by abnormalities in genome (rare and typical caused by the presence of two recessive alleles)

Note: most genetic disorders are not caused by dominant alleles

Question 13

Abnormal number of chromosomes

Answer 13

When children are born with missing, extra, or damaged chromosomes developmental disruptions occur

(More common than inherited disorders)

Question 14

Single-gene inheritance

Answer 14

Phenotypes that rely on the make up of a single gene

Question 15

Polygenetic Inheritance

Answer 15

Phenotypes that reflect the combined activity of many separate genes

(Example: eye color, skin color)

Question 16

Genotype to phenotype

Answer 16

Genotype leads to a phenotype but only if the environment cooperated in the usual manner

(Some genotypes only lead to phenotype if certain environment is present)

Question 17

Epigenesis

Answer 17

Continuous interplay between genes and multiple levels of the environment (from cells subculture) driving development

Question 18

Niche-picking

Answer 18

Deliberately seeking out environments that fit ones heredity

Question 19

Heritability coefficient

Answer 19

Estimates the extent to which differences between people reflect heritability

(Heritability coefficients apply to groups in certain environments not individuals)

Question 20

Behavioral genetics

Answer 20

Determining the impact of heredity on behavioral and psychological traits

Methods of behavioral genetics: twin studies, adoption studies

Genetic inheritance is never the sole determinant of behavioral development – always need to consider role of the environment

Question 21

Twin studies

Answer 21

Strong genetic influence is seen when identical twins look more similar than fraternal twins

Limitations: do people treat identical twins more similarly then fraternal twins

Question 22

Monozygotic Twins

Answer 22

Identical twins come from a single fertilized egg that splits in two (share the same genetic make up for body structure, height, and facial features)

Question 23

Dizygotic Twins

Answer 23

Fraternal twins come from two separate fertilized eggs (by separate sperm)

Share about half of their genes

Question 24

Adoption studies

Answer 24

Adopted children can be compared to: biological parents because of genes and adopted parents because of influence of environment

Limitations: often adoption agencies place children with a family similar to their biological family, If adoptive and biological parents are similar it becomes too difficult to assess environment and genetic influence