Your DNA is like a book of instructions that directs what traits you will get. In humans, DNA is very organized and packaged into chromosomes . We get 23 chromosomes from our mother and 23 from our father for a total of 46 chromosomes. Each of these chapters that codes for a specific trait is called a gene. So, a gene is a small piece of DNA that has information about one of your traits.
Genes come in pairs.
Each person receives one copy of a gene pair from his mother and one from his father. Even though you get half of your genes from your mother and half from your father, each of your parents contributes to all your traits . For the each trait, there are different versions of a gene. Different versions of a gene are called alleles . Although you can have two different alleles, you usually only express one of them.