The chromosomal theory of inheritance is generally credited to Walter Sutton and Theodor Boveri, who independently proposed the theory in the early 1900s.

Here's a breakdown:

* Walter Sutton (1902): Observed the behavior of chromosomes during meiosis in grasshoppers. He noticed that chromosomes occur in pairs and that these pairs separate during gamete formation, with one chromosome from each pair going to each daughter cell. This observation led him to propose that chromosomes are the carriers of genetic information.

* Theodor Boveri (1902): Studied sea urchin embryos and observed that the chromosomes are essential for normal development. He found that removing or altering chromosomes resulted in abnormal offspring. This confirmed the importance of chromosomes in inheritance.

While both Sutton and Boveri contributed significantly to the development of the chromosomal theory, it is often attributed to both of them.