Chromosomal theory of inheritance was proposed by:

Chromosomal theory of inheritance was independently given by Sutton and Boveri in 1902. The two workers found a close similarly between the transmission of hereditary traits and behaviour of chromosomes while passing from generation to the next through the agency of gametes. Sutton united the knowledge of chromosomal segregation with Mendelian principles and called it the chromosomal theory of inheritance.

T.H. Morgan gave experimental verification to this.