Walter Sutton first
related genetics to the behavior of chromosomes in 1902, showing that the
grasshopper Brachystola has 11 pairs of homologous chromosomes,
and that each sex cell formed during meiosis receives one of each pair
as a consequense of meiosis. By demonstrating that these are independently
assorted during meiosis, following Mendel's observations for hereditary
factors, he was able to suggest that genes were located on chromosomes.
Sutton's mentor at Columbia University, and Nettie
Stevens demonstrated the first direct link
between chromosomes and heredity by showing that sex determination is governed
by separate X and Y chromosomes.