lecture 3-2 (inheritance of traits)

• A trait is a characteristic or feature that can be used to distinguish one individual from another. Traits are inherited and are located on chromosomes.
• Genes are associated with the expression of traits
• Heredity is the study of how traits are passed along from one generation to the next
• Genetics is the study of inheritance and genes
• Gregor Mendel (1822 - 1884) established the principles of heredity with his experiments on pea plants.
• Mendel's genetic experiments with pea plants took him eight years (1856 - 1863) and he published his results in 1865
• Albinism is a recessive trait
• Dwarfism is a dominant trait
• Expression of traits is affected by cellular interactions and environmental factors
• Phenotypes are observable traits that are expressed by an organism.
• In order to express a recessive phenotype, there must be 2 copies of recessive alleles.

  
• A dominant allele is expressed when one allele or more is prent
• Mendel found that when he crossed purple flowers with white flowers, he got all purple flowers. On the next generation, the ratio of 3 purple flowers to white flower