Probability and Punnett Squares

Principle #4

Alleles for different genes usually segregate independently of each other

Principle #3

Each adult has two copies of each gene (one from each parent). These genes segregate each other when gametes are formed.

What did Mendel contribute to our understanding of genetics?

Mendel's principles of heredity, observed through patterns of inheritance, form the basis of modern genetics.

How can we use probability to predict squares?

Punnett squares use mathematical probability to help predict the genotype and phenotype combinations in genetic crosses.

Principle #1

The inheritance of biological characteristics is determined by individual units called genes

How do alleles segregate when more than one gene is involved?

The principle of independent assortment states that genes for different traits can segregate independently during the formation of gametes.

Genotype is inherited, phenotype is determined by genotype

What is the difference between genotype and phenotype?

Principle #2

Where two or more alleles of a gene for a single trait exist, some alleles may be dominant and others may be recessive

Punnett square

diagram that can be used to predict the genotype and phenotype combinations of a genetic cross

Genotype

genetic makeup of an organism

Heterozygous

having two different alleles for a particular gene

Homozygous

having two identical alleles for a particular gene

Probability

likelihood that a particular event will occur

Independent assortment

one of Mendel's principles that states that genes for different traits can segregate independently during the formation of gametes

Phenotype

physical characteristics of an organism