Trait: A characteristic that an organism can pass on to its offspring through its genes.
Gene: A segment of DNA on a chromosome that codes for a specific trait.
Alleles: The different forms of gene.
Dominant alleles: An allele whose trait always shows up in the organism when the allele is present.
Recessive alleles: An allele that is masked when a dominant allele is present.
Hybrid: An organism that has two different alleles for a trait (heterozygous organism).
Gregor Mendel (1822-1884) - Austrian scientist, priest, teacher. He studied genetics with his pea plants in the monastery. And wrote a report why some peas are tall and some are short. Back in his days no one believed his theory. Now he is considered the father of modern genetics.