Mendelian Genetics

Blended inheritance

hereditary material mixed in offspring; can’t be separated once mixed

Inheritance of acquired characteristics

parents modify their traits based on use and life experience; modified traits are passed on to offspring

Particulate theory of heredity/Mendelian genetics

parents transmit heritable factors (genes) that remain distinct from one generation to the next

Gregor Mendel

Austrian monk who studied peas in his monastery

True-breeding

offspring are always identical to the parent

Monohybrid cross

both parents are heterozygous for a single trait

Dihybrid cross

a cross between F1 dihybrids

Test cross

breeding an organism of unknown genotype with a recessive homozygote

Homozygous

alleles are the same

Heterozygous

alleles are different

Dominant allele

determines the appearance of the organism

Recessive allele

no effect on the appearance

Genotype

genetic makeup

Phenotype

physical appearance

Principle of Segregation

two alleles for each character trait are separated (segregated) during gamete production

Principle of Independent Assortment

the segregation of alleles into gametes for one trait is independent of the segregation of alleles for a second trait

Linked genes

genes on the same chromosome (same DNA double helix)

Unlinked genes

genes on two different (non-homologous) chromosomes

Sex (X) linkage

gene located on the X chromosome

Incomplete dominance

one allele is not completely dominant to the other

Polygenic inheritance

phenotype is determined by multiple genes

Environmental effects

phenotype is influenced by both genotype and the environment

Multiplication rule

states that to determine probability, multiply the probability of one event by the probability of the other event

Addition rule

the probability that any one of two or more mutually exclusive events will occur is calculated by adding their individual probabilities