Mendelian Genetics Flashcards
addition or sum rule
the probability that any one of two or more mutually exclusive events will occur can be ascertained by the addition of their individual probabilities
allele
gene variations that arise by mutation and exist at the same relative locations on homologous chromosomes
blending inheritance
hypothetical inheritance pattern in which parental traits are blended together in the offspring to produce and intermediate physical appearance
characteristic/character trait
variation in the physical appearance of a heritable characteristic
dihybrid cross
result of a cross between two true-breeding parents that express different traits for two characteristics
dominant
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
epistasis
antagonistic interaction between genes such that one gene masks or interferes with the expression of another
F1 generation
first filial generation in a cross; the offspring of the parental generation
F2 generation
second filial generation produced when F1 individuals are self-crossed or fertilized with each other
genotype
underlying genetic makeup, consisting of both physically visible and non-expressed alleles, of an organism
heterozygous
having two different alleles for a given gene on the homologous chromosome
homozygous
having two identical alleles for a given gene on the homologous chromosome
hybridization
process of mating two individuals that differ with the goal of achieving a certain characteristic in their offspring
incomplete dominance
in a heterozygote, expression of two contrasting alleles such that the individual displays an intermediate phenotype
linked genes
phenomenon in which alleles that are located in close proximity to each other on the same chromosome are more likely to be inherited
monohybrid cross
result of a cross between two true-breeding parents that express different traits for only one characteristic
multiplication or product rule
probability of two independent events occurring simultaneously can be calculated by multiplying the individual probabilities of each event occurring alone
P1 generation
parental generation in a cross
pedigree
diagram that shows the occurrence and appearance of phenotypes of a particular gene from generation to generation
phenotype
observable traits expressed by an organism
principle of independent assortment
describes how different genes independently separate from one another when reproductive cells develop
principle of segregation
describes how pairs of gene variants are separated into reproductive cells
probability
a measure of the likelihood of a statement or a theoretical expectation is correct
Punnett square
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
recessive
disappear in offspring of hybridization
reciprocal cross
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
testcross
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
transmission genetics
a branch of genetics dealing with the study of inheritance in people
true breeding
any crosses performed will result in offspring with the same phenotype, indicating that the organism is homozygous for every gene
