[2] He was invited by Homi Bhabha to set up the molecular biology unit at the Tata Institute of Fundamental Research (TIFR) in Bombay in 1962.

Thirty years later, he became the founding director of the TIFR National Center for Biological Sciences in Bangalore, where he would continue his research into his final days of life.

In the 1970s, his work with Seymour Benzer[4] at Caltech led to the discovery of temperature-sensitive paralytic Drosophila mutants and the generation and transmission of neural signals.

At TIFR, Siddiqi and his graduate student, Veronica Rodrigues,[6] isolated and characterized the first collection of mutants with defects in smell and taste in Drosophila.

Siddiqi's work in neurogenetics led to the foundational advances in understanding how taste and smell are detected and encoded in the brain.