Mendelian Genetics

Question 1

addition or sum rule

Answer 1

the probability that any one of two or more mutually exclusive events will occur can be ascertained by the addition of their individual probabilities

Question 2

allele

Answer 2

gene variations that arise by mutation and exist at the same relative locations on homologous chromosomes

Question 3

blending inheritance

Answer 3

hypothetical inheritance pattern in which parental traits are blended together in the offspring to produce and intermediate physical appearance

Question 4

characteristic/character trait

Answer 4

variation in the physical appearance of a heritable characteristic

Question 5

dihybrid cross

Answer 5

result of a cross between two true-breeding parents that express different traits for two characteristics

Question 6

dominant

Answer 6

trait which confers the same physical appearance whether an individual has two copies of the trait or one copy of the dominant trait and one recessive trait

Question 7

epistasis

Answer 7

antagonistic interaction between genes such that one gene masks or interferes with the expression of another

Question 8

F1 generation

Answer 8

first filial generation in a cross; the offspring of the parental generation

Question 9

F2 generation

Answer 9

second filial generation produced when F1 individuals are self-crossed or fertilized with each other

Question 10

genotype

Answer 10

underlying genetic makeup, consisting of both physically visible and non-expressed alleles, of an organism

Question 11

heterozygous

Answer 11

having two different alleles for a given gene on the homologous chromosome

Question 12

homozygous

Answer 12

having two identical alleles for a given gene on the homologous chromosome

Question 13

hybridization

Answer 13

process of mating two individuals that differ with the goal of achieving a certain characteristic in their offspring

Question 14

incomplete dominance

Answer 14

in a heterozygote, expression of two contrasting alleles such that the individual displays an intermediate phenotype

Question 15

linked genes

Answer 15

phenomenon in which alleles that are located in close proximity to each other on the same chromosome are more likely to be inherited

Question 16

monohybrid cross

Answer 16

result of a cross between two true-breeding parents that express different traits for only one characteristic

Question 17

multiplication or product rule

Answer 17

probability of two independent events occurring simultaneously can be calculated by multiplying the individual probabilities of each event occurring alone

Question 18

P1 generation

Answer 18

parental generation in a cross

Question 19

pedigree

Answer 19

diagram that shows the occurrence and appearance of phenotypes of a particular gene from generation to generation

Question 20

phenotype

Answer 20

observable traits expressed by an organism

Question 21

principle of independent assortment

Answer 21

describes how different genes independently separate from one another when reproductive cells develop

Question 22

principle of segregation

Answer 22

describes how pairs of gene variants are separated into reproductive cells

Question 23

probability

Answer 23

a measure of the likelihood of a statement or a theoretical expectation is correct

Question 24

Punnett square

Answer 24

visual representation of a cross between two individuals in which the gametes of each individual are denoted along the top and side of a grid and the possible zygotic genotypes are recombined at each box in the grid

Question 25

recessive

Answer 25

disappear in offspring of hybridization

Question 26

reciprocal cross

Answer 26

paired cross in which the respective traits of the male and female in one cross become the respective traits of the female and male in the other cross

Question 27

testcross

Answer 27

cross between a dominant expressing individual with an unknown genotype and a homozygous recessive individual; the offspring phenotypes indicate whether the unknown parent
has a heterozygous or homozygous dominant trait

Question 28

transmission genetics

Answer 28

a branch of genetics dealing with the study of inheritance in people

Question 29

true breeding

Answer 29

any crosses performed will result in offspring with the same phenotype, indicating that the organism is homozygous for every gene