It is easier to understand genetics and the link to diabetes by learning some of the basic terms used to study the inheritance of biological characteristics. These include:

• Chromosomes. Rod-shaped element in the nucleus (center) of each cell. Chromosomes contain the hereditary information that guides all cell actions. A person typically has 46 chromosomes, and one set of 23 chromosomes is inherited from each parent. The sex-determining chromosomes X and Y are two of the 46 chromosomes.
  
  
• Genes. The basic unit of hereditary. Each gene is located in a specific site on a chromosome. Each human cell has about 20,000 to 25,000 genes. A person inherits two copies of each gene, one from each parent. They help determine physical characteristics such as eye color and skin color. Genes also contribute to other characteristics in which environment and behavior play a role, such as body weight, intelligence and the risk of diabetes and other diseases. How genes are involved in diabetes is not clearly understood.
  
  
• Genome. All of the genetic material in an organism’s chromosomes.
  
  
• DNA (deoxyribonucleic acid). A complex substance in genes that contains genetic information needed to make the body’s proteins. These proteins allow the body to function and grow.
  
  
• Allele. Variations of a single gene. An individual’s genes have two alleles, one inherited from the mother and one from the father. Differences in alleles are one factor involved in differences among people in physical characteristics and susceptibility to disease.