Genetics

Heredity Passing of genetic traits from parent to offspring Gregor Mendel discovered the principles of heredity while studying pea plants (“Father of Genetics”) Genetics- scientific study of heredity

Trait Different forms of a characteristic (hair color)

Gene Segment of DNA on a chromosome that codes for a specific trait One set of instructions for an inherited trait

Allele Different forms of a gene 2 types –Dominant allele –Recessive allele

Dominant- trait always shows up in the organism when allele is present (shown with capital letter) Tall is Tt or TT Recessive- trait masked when a dominant allele is present (shown with lower case letter of dominant allele) Short is tt Allele

Pure Bred Will have 2 of the same alleles TT for tallness tt for shortness Homozygous (another name)

Hybrid Carries both a dominant allele and a recessive allele (will always show dominant trait) Tt for tallness Heterozygous (another name)

Phenotype Is the organism’s physical appearance of its visible trait

Genotype Is the organism's genetic makeup or allele combination Genotype ratio is written Pure dominant: hybrid: pure recessive

Punnett Square Chart that shows all possible combinations of alleles that can result from a genetic cross

Codominance Inheritance pattern in which the alleles share dominance Both alleles are expressed Ex. Roan Cow- the alleles for fur color are codominant Written as capital letters

Incomplete Dominance Inheritance pattern in which the alleles are neither dominant nor recessive but blend together Red flower and white flower make a pink flower