Lesson 5: Genetics and Heredity

Heredity is how traits pass from parents to offspring. Gregor Mendel, a monk who bred pea plants, figured out the basic rules and is called the father of genetics.

The Vocabulary You Must Know

• ●Allele: a version of a gene (you get one from each parent)
• ●Dominant: an allele that shows up even if only one copy is present (written as a capital letter)
• ●Recessive: an allele that only shows when both copies are present (written as a lowercase letter)
• ●Genotype: the actual alleles you carry, like Bb
• ●Phenotype: the trait you can see, like brown eyes
• ●Homozygous: two matching alleles (BB or bb)
• ●Heterozygous: two different alleles (Bb)

Punnett Squares

A Punnett square is a box that predicts the chance of offspring traits. You put one parent's alleles across the top and the other parent's down the side, then fill in the combinations.