By 1902, the chromosome movement during meiosis had been worked out.
Walter Sutton and Theodore Boveri (1902) noted that the behaviour of chromosomes was parallel to the behaviour of genes and used chromosome movement to explain Mendels laws.
They studied the behaviour of chromosomes during mitosis (equational division) and during meiosis (reduction division). The chromosomes as well as genes occur in pairs and the .two alleles of a gene pair are located on homologous sites of homologous chromosomes.
Chromosomes segregate when germ cells are formed.