1. Mendelian Inheritance

Question 1

Law of Segregation

Answer 1

alleles separate into different gametes, each individual has 2 alleles for each trait, one from each parent

Question 2

Law of Independent Assortment

Answer 2

alleles segregate independently, inheriting one allele doesn’t increase/decrease chance of inheriting another allele, (exception for alleles on same chromosome)

Question 3

Law of Dominance & Uniformity

Answer 3

traits can be dominant or recessive, need two copies to be recessive, one copy to be dominant, dominant traits mask recessive traits

Question 4

Monohybrid Cross

Answer 4

crossing two individuals with one trait

Question 5

Test Cross

Answer 5

crosses a true-breeding recessive individual with an individual that expresses the dominant phenotype, determines if individual is heterozygous or homozygous

Question 6

Dihybrid Cross

Answer 6

crossing two individuals with two traits, P1 is two true-breeding individuals, F1 are heterozygous, F2 follow 9:3:3:1 inheritance pattern

Question 7

Product Rule

Answer 7

probability that 2 independent events is the probability of each individual event, multiplied

Question 8

Pedigree

Answer 8

family tree that tracks a single trait

Question 9

Autosomal

Answer 9

not sex-linked

Question 10

Sex-Linked

Answer 10

trait that is present on sex chromosomes

Question 11

Autosomal Recessive

Answer 11

Examples: Tay-Sachs disease, Cystic Fibrosis, sickle cell anemia, albinism
- typically skips generations
- males/females affected similarly
- 25% prevalence when both parents are heterozygous

Question 12

Autosomal Dominant

Answer 12

Examples: Huntington’s, neurofibromatosis, achondroplasia, familial hypercholesteremia
- typically does not skip generations
- males/females affected similarly
- affected child MUST have affected parent
- 50% prevalence when one parent is affected

Question 13

X-Linked Recessive

Answer 13

Examples: Red-green colorblindness, Duchenne muscular dystrophy, Hemophilia A
- typically skips generations
- affects males more than females
- affected fathers do not pass it down to sons, but make their daughters carriers
- affected females must have affected father
- 50% prevalence when one parent is affected

Question 14

X-Linked Dominant

Answer 14

Examples: Rett Syndrome, Hypophatemic rickets, ornithine transcarbamylase deficiency
- typically does not skip generations
- affects females more than males (has double the chance of inheriting it)
- affected mothers pass it on to their sons
- affected fathers do not pass it on to their sons
- affected fathers pass it down to all daughters

Question 15

Y-Linked Traits

Answer 15

Examples: hearing loss
- only affects males
- fathers pass it down to all sons
- typically does not skip generations

Question 16

Pleiotropy

Answer 16

Examples: Marfan syndrome, phenylketonuria
- one gene affects multiple traits

Question 17

Polygenic Traits

Answer 17

Examples: height, Type 2 Diabetes, most traits/disorders
- multiple genes TOGETHER affect one trait

Question 18

Genetic Heterogeneity

Answer 18

Examples: predisposition to breast cancer, inherited hearing loss, mental illness
- multiple genes SEPARATELY can affect one trait

Question 19

Penetrance

Answer 19

the proportion of people in a population who actually develop the trait

Question 20

Expressivity

Answer 20

the degree to which a trait is expressed

Question 21

Incomplete Dominance

Answer 21

Examples: heterozygous for familial hypercholesteremia will have intermediate LDL levels
- both phenotypes are represented as a mixed phenotype, “intermediate”

Question 22

Codominance

Answer 22

Examples: both normal and sickled blood cells in sickle cell anemia
- both phenotypes are expressed equally

Question 23

Epistasis

Answer 23

Examples: alopecia masks hair color due to baldness
- one gene masks the expression of another gene, one gene acts dominant over the other

Question 24

Lethal Alleles

Answer 24

Examples: homozygous dominant achondroplasia is lethal
- cannot survive with allele

Question 25

Germline DNA

Answer 25

gamete DNA from both parents, 3.2 billion base pairs

Question 26

Mitochondrial DNA

Answer 26

DNA housed in the mitochondria, passed down from mother, 16,000 base pairs

Question 27

Linkage

Answer 27

two genes on the same chromosome may be inherited together if they are close enough, do not independently assort