Genetics Vocabulary SY2021 Heredity - Passing traits from parent to offspring Genetics - The study of heredity and variation in organisms DNA - The genetic material which determines the traits of the organism, found in the nucleus of the cells Chromosomes -Threadlike strands of DNA and proteins that code for the traits of the organism Gene - A distinct unit of hereditary material on the chromosome Allele - Different forms of a gene controlling a particular trait Dominant allele - T The form of a gene that can mask the recessive allele. The form that is expressed or “shown.” Recessive allele - t The form of a the gene that can be masked or hidden by the dominant allele. Heterozygous - Tt An organism that has two different allele for a trait. Homozygous -TT tt An organism that has two of the same alleles for a trait. Genotype - The genetic makeup of an organism. Phenotype - The physical traits of an organism. What is seen. Purebred - TT tt Homozygous, has two of the same alleles for a trait. Hybrid –Tt Heterozygous, has two different alleles. Punnett Square - A diagram to show the possibilities of traits for the offspring of “parents”. Cross - Punnett square, showing the possibilities of traits combining for offspring from the parents. Probability - The chance or percentage of offspring having certain traits.