Hugo J. Bellen is a professor at Baylor College of Medicine and an investigator emeritus at the Howard Hughes Medical Institute[8] who studies genetics and neurobiology in the model organism, Drosophila melanogaster, the fruit fly.

Hugo Bellen is a Distinguished Service Professor at Baylor College of Medicine (BCM) in the Departments of Molecular and Human Genetics and Neuroscience and an Investigator Emeritus at the Howard Hughes Medical Institute.

One of the world's premier researchers in Drosophila (fruit fly) genetics, Dr. Bellen's group has made major contributions to our understanding of nervous system development, synaptic transmission and mechanisms of neurodegeneration.

He was previously on the scientific advisory boards of the Max Planck Institute in Göttingen, Germany, the Academia Sinica in Taipei, Taiwan, the KAIST in Daejeon, Korea, and the VIB in Leuven, Belgium.

Bellen was a leader in the development of P element-mediated enhancer detection which allows for discovery and manipulation of genes and was the impetus for a collaborative and ongoing project to generate an insertion collection for the community.

Furthermore, Bellen and colleagues devised a new transformation technology that permits site-specific integration of very large DNA fragments,[18] which led to the generation of a collection of flies carrying molecularly defined duplications for more than 90% of the Drosophila X-chromosome.

Most recently his lab created a new transposable element (MiMIC)[20] that permits even more downstream manipulations via RMCE (recombinase-mediated cassette exchange), such as protein tagging and knockdown[21][22] and large scale homologous recombination.

Bellen and colleagues made important contributions to our understanding of Drosophila peripheral nervous system development and the fine-tuning of aspects of Notch signaling during this process.