[1][2] A contemporary of Watson and Crick,[3] he spent a significant part of his international career heading the Department of Somatic Cell Genetics at Memorial Sloan Kettering Cancer Center in New York,[4] but throughout his life maintained ties to his home country of Italy.

[5][6] Siniscalco also played an important role in the development of the Human Genome Organisation (HUGO) in its early years,[7] and was ultimately awarded the title of Commendatore by the Italian government in recognition of his contributions to his field.

By the time of the outbreak of World War II, a teenaged Siniscalco moved with his family to the small town of Cava de' Tirreni, fifty kilometres from Naples, in order to escape the heavy Allied bombardments of the city and its harbour.

Although he never pursued a career as a practising doctor, it was his training in biology, and the tutelage of his mentor Professor Giuseppe Montalenti during the late 1940s and early 1950s at the Stazione Zoologica at the Naples Aquarium, that enabled Marcello to discover the nascent field of genetics.

This was one of the earliest known works attempting to understand the link between DNA and RNA (the central dogma of molecular biology), contributing to a school of academic thought which culminated in Watson and Crick’s Nobel-prize winning discovery a decade later.

However, due to early trips to symposia abroad to institutions such as MIT (1958) and elsewhere, the draw of international science proved too much, and within a decade, Siniscalco accepted an invitation to found and chair a new Department of Genetics at Leiden University, Netherlands (1962).

Haldane, Siniscalco organized and financed a field trip to Andhra Pradesh, India, an expedition designed to find isolated populations that might offer more statistically significant data sets.

Marcello therefore accepted an invitation as Visiting Professor to the Albert Einstein College of Medicine (New York City) where he participated actively in the development of human somatic cell genetics department, while still maintaining his Professorship at the University of Naples.

In July 1989, Siniscalco returned to Italy, enticed by a government program designed to lure back the leading expatriate scientists of his generation, including contemporaries such as his close friends Luigi Luca Cavalli-Sforza, Rita Levi-Montalcini and Renato Dulbecco.

After almost 20 years of commuting to Sardinia for data collection, Siniscalco, recognized as a "world-class researcher,"[26] could finally pursue his dream to found and create a Sardinian Center for Studies of Genome Diversity in Porto Conte.

[28][29][30][31][32][33] Marcello also played an important role in the development of the Human Genome Organisation (HUGO) in its early years, which had the added benefit of allowing his young family to reside in London while he commuted back and forth to Alghero, Sardinia.

During the last decade of his career, Siniscalco became a Professor of Genetics and consultant for population genomics at the Coriell Institute for Medical Research (in Camden, New Jersey), where his vision was to "immortalize" the bulk of the many samples he had collected over the years for future generations to analyze.