Heredity refers to the passing of characteristics from parents to offspring. Genetics is the study of heredity, genes and variations in organisms. Heredity occurs in plants, animals, bacteria and fungi.
Organisms inherit physical characteristics or traits from their parents or ancestors. This is the reason offspring often resemble their parents. Cells of living organisms contain tiny biochemical structures called genes. The genes are responsible for carrying traits from one generation to the next. Genes get shuffled during reproduction, resulting in offspring with varying characteristics. Some traits are the result of the interaction of several genes. Genes are made up of a chemical called DNA, or deoxyribonucleic acid, which is strung together in long chains called chromosomes.
Gregor Mendel is considered the father of genetics. He studied the nature of inheritance in pea plants. In his experiments, he discovered that the color of the flowers were either purple or white and not a mixture of the two colors. He observed that pea plants inherit traits through units of inheritance. These units of inheritance were later named genes.
Some diseases, such as sickle-cell anemia, are genetic. A small difference in DNA can result in sickle-cell anemia. The environment also influences the expression of a gene. A person may be genetically predisposed to obesity, but the actual weight of the person depends on diet and lifestyle.