Sutton and Boveri Chromosome Theory of Heredity:
Walter Sutton (1902) studied meiosis in grasshopper testes and brought out the association between paternal and maternal chromosomes. Theodor Boveri (1902) demonstrated in sea urchins that different chromosomes of each set possess different qualities. From these observations, Sutton and Boveri recognized a parallelism between the behavior of chromosomes during meiosis and the behavior of Mendelian factors or genes during the formation of gametes. He proposed the chromosome theory of heredity. The parallelism exists in the following features:
1. Genes occur in pair so are the chromosomes.
2. The members of a gene pair segregate equality into gametes. The homologous chromosomes of each chromosome pair also segregate equally.
3. Different gene pairs act independently, and so do the different chromosome pairs.