The specific genes, which are different from one person to another and give each person special physical features, are named alleles. Each person carries a copy of genes from each parent. Made of deoxyribonucleic acid (DNA) bases, a gene can carry a couple of hundred to over two million DNA bases.
Since DNA has stored chemical information, a gene carries coded instructions for a specific protein or for performing a specific function. Each person is said to have 20,000 to 25,000 genes, according to the Human Genome Project.Learn more about Molecular Biology & DNA