What is Genetics? Genetics is the study of how traits such as hair color, eye color, and risk for disease are inherited from parents to their children. Genetics influence how these inherited traits can be different from person to person. Your genetic information is called your genetic code or genome.
Your genome is made up of a chemical called deoxyribonucleic acid DNA and is stored in almost every cell in your body.
DNA contains four basic building blocks or bases: adenine A , cytosine C , guanine G and thymine T. The order, or sequence, of these bases form the instructions in the genome. DNA is a two-stranded molecule. What is a Gene? A gene is the basic physical and functional unit of heredity. Genes are made up of DNA. Some genes act as instructions to make molecules called proteins. However, many genes do not code for proteins.
In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases. The Human Genome Project estimated that humans have between 20, and 25, genes. Every person has two copies of each gene, one inherited from each parent. Most genes are the same in all people, but a small number of genes less than 1 percent of the total are slightly different between people.
Alleles are forms of the same gene with small differences in their sequence of DNA bases. These small differences contribute to each person's unique physical features. What is a Genome? Your genome is your entire genetic code or all of the DNA in a cell. What is a Chromosome? In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes.
