Heredity and Genetics Heredity and Genetics I wonder

Heredity and Genetics

Heredity and Genetics I wonder… is square dominant over round for sponge shape? ? ?

HEREDITY The inheritance of traits from parents to offspring

GENETICS the study of heredity

TRAI A characteristic that T distinguishes one individual from another.

Gregor Mendel • Considered the “father of genetics” • An Austrian monk with a love of science • Experimented with garden peasstudying traits such as plant height, pea color, pea shape, flower color • Began his experiments in 1856 • Experimented for 8 years on thousands of plants • His work was forgotten until other scientists confirmed his findings in 1900

Alleles • The different forms of a trait that a gene may have Examples in pea plants include: • Short or tall plant • Red or white flowers • Green or yellow peas

GENE CHROMOSOME ALLELE is a part of a chromosome that determines a trait. ALLELES ALLELE are different forms of a gene.

Alleles • Alleles can be DOMINANT: meaning they cover up (dominate) other alleles; or they can be recessive: meaning they can be covered up or seem to disappear • The different alleles are shown by CAPITAL (DOMINANT) or lowercase (recessive) letters

Alleles • How do you determine which allele is dominant to begin with? ? ? • For the recessive allele or form of a trait to be seen, the genotype MUST be a pure (homozygous) recessive (tt) • The dominant form will show in either pure (homozygous) dominant OR heterozygous (mixed) (TT or Tt)

Alleles • If the alleles are the same they are called homozygous. (also known as purebred) • Example: TT or tt • If the alleles are different they are called heterozygous. (also known as hybrid ) • Example: Tt