Thread by @Planaria1

I am on my way to @SastraUniv to receive the 2019 Obaid Siddiqi Award.

I want to pause and reflect on the fundamental contributions made by this extraordinary Indian mind and global scientist to human knowledge.

@ScienceStowers @royalsociety @theNASciences

I never met Obaid, but I first learned of Dr. Siddiqi when I was learning about fine cistron (gene) mapping in college @VanderbiltU in the early 1980s from Dr. Gisela Mosig

en.m.wikipedia.org/wiki/Gisela_Mo…

Obaid’s Ph.D. thesis (1961) reported an unusual concentration of mutations in a small part of an allele of the paba1 gene of the fungus Aspergillus nidulans

cambridge.org/core/services/…

Soon after (1962), together with Aleksandra Putrament (a geneticist who deserves her own thread), Obaid used intragenic recombination to suggest polarized negative interference.

cambridge.org/core/services/…

Both of these articles demonstrated how new molecular biology approaches could be used to map mutations, methods that were soon adopted by biologists across the globe and made Obaid an internationally acclaimed scientist.

He was barely 30 years old.

Obaid moved to @CSHL & later @UPenn, where he found nonsense mutations in E. coli while studying an external suppressor for a class of mutations in the alkaline phosphatase gene

pnas.org/content/pnas/4…

In essence, Obaid had discovered both a nonsense mutation and its suppressor.

This work led to the elucidation of stop codons in the genetic code & the mechanism of chain termination during protein synthesis.

In 1962, Siddiqi accepted the invitation to create the Molecular Biology Unit (now the Department of Biological Sciences) at the Tata Institute of Fundamental Research (TIFR) in Bombay @TIFRScience

Obaid thus launched India’s entry into modern biology.

He was 30 years old.

At Bombay, with his student PV Sarathy, he extended his previous finding that recombinant bacteria inherit DNA of bi-parental origin to demonstrating conditions where conserved un-replicated DNA can be used for conjugation.

link.springer.com/article/10.100…

link.springer.com/article/10.100…

This work amongst others established many of the basics of bacterial conjugation and laid the founding principles underpinning lateral gene transfer.

Obaid became very good friends with Seymour Benzer @Caltech and the two maintained extensive correspondence through the years.

en.m.wikipedia.org/wiki/Seymour_B…

artsandculture.google.com/asset/obaid-si…

ia903007.us.archive.org/17/items/ncbs.…

Obaid and Seymour teamed up in describing the different neurophysiological phenotypes of three temperature sensitive paralytic mutants comatose, para and sh

pnas.org/content/pnas/7…

Their work laid the foundation for the use of temperature sensitive block of synaptic recycling now routinely being used to have spatiotemporal control of neural activity to map circuitry in the fly brain.

Obaid contributions in genetic neuroscience would continue in the coming decades

His trainees excelled and helped establish fields in both India and abroad.

countercurrents.org/khurana300713.…

Obaid embraced complexity, and never seemed to have shied away from a scientific challenge.

Obaid eventually 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.

@NCBS_Bangalore

In the hands of Obaid, the fungus Aspergillus, the bacteria E. coli & the fruitfly Drosophila gave us:
1. Fine mutation mapping
2. Non-sense mutations and stop codons
3. Lateral gene transfer
4. The genetics of behavior along with Seymour Benzer and Sydney Brenner

Science needs bright, curious minds hailing from all parts of the world, supportive communities to nurture such minds, & ecosystems that allow their curiosity to take us into the unknown.

Their light always expands the breadth and depth of human knowledge.

Thank you, Obaid.