Organization Every living thing has a set of characteristics inherited from its parent or parents. This is called heredity. Genetics is the study of heredity, or the inheritance of traits. Our traits are coded for by genes, or sections of DNA that are packaged into chromosomes.

The same gene can have many versions. Allele The same gene can have many versions. Allele alternative form of a gene Each gene has a locus, a specific position on a pair of homologous chromosomes. Alleles can be represented using letters. A, B, C, ……

Dominant and Recessive Dominant allele mask the recessive allele from being expressed. Dominant alleles are represented by uppercase letters A Recessive allele is the allele that is masked by the dominant trait. recessive alleles by lowercase letters a Only expressed when both alleles are recessive

Homozygous and Heterozygous Each parent donates one allele for every gene. Homozygous- two alleles that are the same at a specific locus. (AA or aa) Heterozygous- two alleles that are different at a specific locus. (Aa)

Phenotype and Genotype Physical characteristic What you can see: Color (Green or yellow) Height (tall or short) Shape (round or wrinkled) Genotype Genetic make up of the organisms What alleles it has: GG, Gg, gg TT, Tt, tt RR, Rr, rr Phenotype: GREEN Genotype: GG or Gg Phenotype: Yellow Genotype: gg