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Chapter 3, section 2 Study Notes – Probability and Genetics
An organism’s physical appearance is its phenotype.
An organism’s genotype is its physical makeup.
A Punnett square shows all the possible outcomes of a genetic cross.
An organism that has two identical alleles for a trait is homozgyous.
The probability of producing a tall plant from a genetic cross of two hybrid
tall plants is three in four.
Probability is the likelihood that a particular event will occur.
A heterozygous organism has two different alleles for a trait.
A homozgyous black guinea pig (BB) is crossed with a homozgyous white
guinea pig (bb) the probability that the offspring will have black fur is 100%.
A Punnett square shows all the possible combinations of alleles in offspring.
Codominance in genetics means that the alleles are neither dominant nor
recessive.