GENES, PEOPLE AND LANGUAGES
Luigi Luca Cavalli-Sforza
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The title of the book explains perfectly the three main topics it deals with: the research on genes to
study human evolution and migration, linked to that the origin and diffusion of the languages.
The ambitious goal of this book is that of surveying the research of human evolution combining the
different fields of study that contribute to our knowledge: genetics, archaeology and linguistics. We
may also add that there are some implications for important social problems, among that racism.
Starting from what is genetic variation and its theories, Cavalli-Sforza sets the bases to explain how
the use of the “tree-building method” works to determine how populations are genetically related to
each other. The author introduces the main evolutionary forces that has been identified and explains
how these influence human evolution and migration. Cavalli-Sforza demonstrates how the study of
genetics can provide the tools to determine where our first ancestors appeared, the “African Eve”
and “Adam”, and that the difference in genetic flow of males and females can help to clarify ancient
migrations. Since for genetic mobility where people settle for marriage is important, a simple
explanation is that usually it is the woman who changes her residence to join her husband.
Thanks to the correlation between genetic and geographic distances, the principal components
analysis (a set of data represented in a simple way graphically) can be applied to genetic distances
between the possible pairs of world populations in order to reconstruct a map of the world. The
result is that every population has originated in more than one continent. Moreover, starting from
where modern humans’ history took place, it is possible to determine the successive steps of human
migration. And what helps human to explore and establish small societies, adapting to new
environments and therefore to develop his language. It is considered an important instrument of
communication. Nonetheless expansions across wide geographic areas help the mixing between
populations, leaving traces in the genes. Hence, according to Cavalli-Sforza, it is possible to path
ancient migrations while drawing maps that summarize all possible gene frequency information.
Usually genetic consequences of the expansion of the population depend on the number of migrants
and on the number of inhabitants in the occupied region.
As for the relationship between genes and languages, it has been suggested that parent languages
giving rise to a family must be reconstructed to demonstrate a relationship. It is not certain that all
languages share a common origin: a family may correspond to one or more branches in the genetic
tree. But between evolution of genes and languages there are important similarities: a change that
first appears in an individual can spread throughout the entire population.
One important aspect that makes humans differ from animals is the richness and importance given
to their culture. This is defined as the ability to learn from the experience of others and to
accumulate previous discoveries, relying on the communication between one transmitter and one
receiver. For this reason it is similar to genome: information is transmitted through generations.
Cavalli-Sforza concludes that from one side cultural development has slowed biological evolution
but on the other migrations are creating an increased mixing of population diminishing genetic
differences. Even with a gradual increase of cultural change, the reasons for racism will reduce.
