Jyoti Vakhlu
jyotivakhlu@jammuuniversity.ac.in
From laws of inheritance to the molecule of heredity – a journey of scientific triumphs, ethical fault-lines and the end of an era with the passing of the maestro.
In the time when DNA is used in everyday phrases, the philosophical thoughts on inheritance, before Mendel may seem laughable today . Aristotle suggested that parental traits mix in offspring. That is, the parental traits blend not as discrete units but like paint, that two different paints are mixed and a new colour that is a mix of two is formed. This thought did not meet reality, as in the population, a long silent trait would all of sudden show its presence, in the third or fourth generation of the organism. This puzzle was solved partially by August Weismann, when he demonstrated that the germ line cells are different from somatic cells and are the ones responsible for inheritance, contrary to the contemporary thoughts .
In the mid-19th century, Gregor Mendel conducted experiments with pea plants that laid the foundation of genetics by establishing the laws of dominance, segregation and independent assortment of traits. He called these traits factors, suggesting they were discrete physical units, and the nature of these units was unknown at that time. Mendel’s discovery provided a framework for heredity but left the deeper mystery unanswered : how was the trait-bearing material arranged at the molecular scale? Over subsequent decades the chromosome theory of inheritance brought genes into the picture. Most scientists believed proteins to be responsible for inheritance, as chemically chromosome has both DNA and protein. But in 1944, the landmark experiment by Oswald T. Avery, Colin MacLeod and Maclyn McCarty demonstrated that it was actually DNA that carries information for heredity, that was subsequently confirmed by Alfred Hershey and Martha Chase in 1952
Interestingly around the same time in 1944 the Austrian physicist Erwin Schrödinger, a figure instrumental to quantum physics, asked a bold, provocative question in his book , “What Is Life?” : It was he who hypothesised that living cells must house an “aperiodic crystal” – a stable structure capable of carrying information, hinting at the molecular code of life. The importance of all these findings and thoughts were very significant as they didn’t just change our experiments but rather our perspective. Moving forward we switched from the very tangible markers of life – growth, reproduction, respiration, to more abstract ones – the biochemistry that makes it all happen. This hypothesis by Schrödinger led to the conceptual leap that set the stage for one of science’s greatest discoveries: the structure of DNA, the molecule of life. And this story not only reshapes how we understand life and heredity today but it shows how creativity and free thought is central to scientific endeavour as it is to art.
In 1953, James D. Watson and Francis Crick (building on key work by Rosalind Franklin and Maurice Wilkins) unveiled the double-helix structure of DNA: two intertwined strands whose paired chemical bases offered a mechanism for replication and information transfer. To discover the structure of DNA , the molecule of life was the dream of many scientists but the model proposed by Watson and Crick was immediately accepted as the structure explained how this molecule is capable of self replication. This explained the basic characteristic of living that is reproduction. The double helix discovery paved the way for genomics, molecular diagnosis, gene therapy, genome editing, and synthetic biology.
Yet overshadowing his legacy are persistent controversies: questions of data credit (particularly Rosalind Franklin’s contributions) and inflammatory remarks by Watson on genetics, race and intelligence. According to multiple historical accounts, Watson and Francis Crick used this data (or derived insight from it) seemingly without Franklin’s direct knowledge or full consent. It is said that the famous x-crystallographic “Photo 51” taken by Rosalind Franklin was shown to Watson by Maurice Wilkins, who was Franklin’s boss at that time . Wilkins later shared the Nobel with the duo in 1962. In later parts of his life , Watson made a number of public statements asserting that genetic factors underlie racial differences in average IQ scores, especially between people of African descent and others. In 2007 he discussed these views in a British newspaper, which led to his stepping down from the chancellor’s role at Cold Spring Harbor Laboratory (CSHL) and his honorary titles were revoked by Cold Spring Harbor Laboratory in 2019.These controversies show that scientific progress occurs within a social and ethical context ; discoveries matter, but so do conduct, recognition and responsibility. Watson’s name appears in both the role of “giant of molecular biology” and “scientific figure whose decisions and remarks warrant critical reflection.” Watson’s death on 6 November 2025 at age 97 marks more than the passing of a person; it symbolises the closing of a foundational chapter in molecular biology. His case reflects the dual nature of scientific genius: extraordinary insight paired with personal and ethical flaws.
(The author is Professor School of Biotechnology University of Jammu)
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