The Chromosomal Basis of Inheritance Locating Genes Along Chromosomes ( 15.1) * Mendel?s ?hereditary factors? were purely abstract when first proposed * Today, we can show that the factors?genes?are located on chromosomes * The location of a particular gene can be seen by tagging isolated chromosomes with a fluorescent dye that highlights the gene * Cytologists worked out the process of mitosis in 1875 and meiosis in the 1890s using improved techniques of microscopy * Biologists began to see parallels between the behavior of Mendel?s proposed hereditary factors and chromosomes * Around 1902, Sutton and Boveri and others independently noted these parallels and began to develop the chromosome theory of inheritance 15.2