mendelian genetics

allele

alternative versions of genes

true breeding

plants that when self crossed always produce the same plant variant

genotype

the genetic makeup of a organism

phenotype

the observable traits of a organism

homozygous

containing identical alleles for a particular trait

heterozygous

containing two different alleles for a particular trait

dominant allele

a variant form that will be observed in a heterozygous

recessive allele

a variant form that will not be observed in a heterozygote

what are punnett squares good for

predicting the genotypes of offspring

what is monohydbrid

heterozygous for a single trait

what is the multiplication rule

the probability that two or more independent events will occur can be calculated by multiplying the probability of each event occurring

what is the addition rule

the probability that any one or two or more mutually exclusive events will occur can be calculated by adding the probability of each event occuring

what is a test cross

cross unknown plant with a recessive true breeding plant

how did mendel develop the law of segregation

by following a single trait at a time

how was the law of independent assortment created

by mendel observing two traits at a time; dihybrid crosses

what is the first law of independent assortment

two or more genes assort independently of one another during meiosis

what is the second law of independent assortment

each allele pair for a separate trait separates independently of how any other trait separates

what happens during meiosis I

two different alleles for a gene separate

what is complete dominance

heterozygote offspring always demonstrate the phenotype of the dominant parental allele

what is incomplete dominance

when the phenotype of a heterozygote looks like a mix of the two parental phenotypes

what is codominance

when two alleles affect phenotype in separate, distinguishable ways

what is an example of codominance

blood type (express both A & B phenotype)

what is pleiotropy

when a single gene has more than one phenotypic effect

what is epistasis

when the expression of a gene affects the expression of another

what is polygenic inheritance

when multiple genes affect a single phenotypic trait