GENETICS VOCABULARY

• • Trait: each variant for a character
• Allele: one of a pair of genes that appear at a particular location on a particular chromosome and control the same characteristic.
• • Dominant Allele: a gene that exerts it’s full effect no matter what it’s allelic partner may have (expressed). The dominant allele is represented by a capitalized letter (ex. A, B, C, D, )
• • Recessive Allele: a gene that is masked by the dominant allele. The recessive allele is represented by a small letter (unexpressed) (ex. a, b, c, d, )
• • Diploid organisms have 2 copies of every gene, therefore they have 2 alleles for a specific trait. 
• • Homozygous: an organism that contains identical alleles (ex. TT or tt). Also called pure-bred
• • Heterozygous: an organism that contains two different alleles (ex. Tt). Also called hybrid
• • Genotype: genetic make-up of an organism or the specific alleles. represented by letters. Ex. TT, Tt, tt
• • Phenotype: the observable appearance of an individual resulting from it’s genotype. Ex. Tall, short (height, color, shape)
• • Punnett square: Genetic problems can be easily solved using this tool for calculating genetic probabilities