If there is one constant in the universe it is change. Cultural changes and genetic changes are continuously in progress all around us, most vividly apparent in the recent arrival of eastern European and African migrants to this country. Along with their dress, their music and their hopes they bring their own genetic heritage. When we speak of race and racism, it is an imperative that all interested parties be capable of clear rational thought. What do these terms specifically mean? What can science contribute to such a debate? To what extent does our personal and political philosophy derive from how we interpret and understand biology? Genes, Peoples and Languages eloquently communicates essential information required by all who wish to navigate the complex relationships that exist between genetic science, evolutionary history, human origins and our social and cultural past. It challenges us to define what we understand of "race" and its author, Luigi Cavalli-Sforza, has for nearly half a century made seminal contributions to the study of evolutionary genetics, in addition to possessing a most wonderful talent for telling a great story. As recently as last June newspapers around the world devoted hundreds of pages to the announcements of immense medical benefit set to emerge from the dissection of the human genome. Lost under all the weighty verbiage was a less documented, but equally valuable benefit, for anyone with an interest in how the human species has journeyed from the forests of Africa to the Fertile Crescent and on to the lifeless valleys on the surface of the Moon. Aside from the rather practical information within our genes for building bones and brains, the 3.3 billion-letter code of human DNA also represents probably one of the greatest social history documents in existence, recording the evolution of the human species into nearly every natural and unnatural environment on Earth and beyond. To geneticists around the globe careful analysis of particular genes, both between our species and others, and between individuals within our species, reveals a treasure trove of information. To a skilled reader the human genome may relay critical information ranging from human migratory routes to the development of spoken languages, even providing microscopic detail on dietary changes in ancient hominids. Researchers are only beginning to catalogue these treasures. Genes, Peoples and Languages superimposes the data emerging from genetics on to equally fascinating studies on the evolution of language and culture. Research from diverse disciplines tackling the same question provides a rich database of information. Archaeological theories might be affirmed from subtle clues in our DNA, while genetic and evolutionary theories may find concrete support from discoveries in the ruins of early settlements. In combination what emerges from the pen of Cavalli-Sforza is a broad canvas upon which the path of humanity itself becomes ever more sharply focused.
If one element emerges from this work, it is a picture of races spanning a continuum of variety rather than a clearly defined margin between one race and another. This is the trend set to continue in the future, where every society - even the island nation of Ireland - will experience ever greater genetic mixing, dissolving both real and apparent differences.
Gearoid Tuohy is a researcher at the Department of Genetics, Trinity College Dublin