Unit 18 Inheritance 18.1 Defining Inheritance Inheritance(heredity) is the transmission of genetic information from generation to generation. 18.2 Chromosomes, genes and proteins Chromosomes are located in the nucleus of cells. A gene is a short length of DNA found on a chromosome that codes for a specific protein. Genes control our characteristics as they code for proteins that play important roles in what our cells do. Alleles are different versions of a particular gene. The ABO gene for blood group type has three alleles, IA, IB and IO