Chromosomal theory' of inheritance was given by

The chromosomal theory of inheritance was given by Sutton and Boveri.
The Boveri–Sutton chromosome theory is a fundamental unifying theory of genetics that identifies chromosomes as the carriers of genetic material.
It correctly explains the mechanism underlying the laws of Mendelian inheritance by identifying chromosomes with the paired factors (particles) required by Mendel's laws.
It also states that chromosomes are linear structures with genes located at specific sites called loci along them.