Our ancient ancestor

I propose the introduction of a new field of study called the Molecular Humanities. It is about exploring the meaning of discovering and describing molecules and their structures. It is affects every field of existing knowledge, cutting through the boundaries of fields of enquiry, as we know it.

Most people know what it is I am talking about in the field of medicine and health. Discovering molecular structures like dysfunctional DNA leads to much better understanding – and potentially, diagnosis and treatment of – disease. The UCT Institute of Infectious Disease and Molecular Medicine are for example about that very connection.

Understanding molecular structure is also becoming increasing useful for understanding human mental states and therefore mental disease. The balance of chemicals in the brain that provide for stability and instability has a repertoire shaped – even determined – by large protein molecules.

Molecular psychiatry is therefore, unsurprisingly, a growing field. Its sister discipline is evolutionary psychology, an organised intellectual enterprise that tries to account for why certain mental states like anger and love are kept in the gene pool of humanity. Love is about attraction, anger about discipline, and both are needed for social cohesion.

Molecules that make up the brain turns it into a search engine for patterns, which then is the same machinery that gives structure to utterances, which is language, and to song, which is music. The same molecules give the machinery to calculate and measure patterns, which is mathematics and physics, and to provide the brain power to plan for humans.

Molecules that affect human cooperation and competition are becoming of interest to economists. Human sociality is of course partly learnt, but the learning is often to curtail natural tendencies such as selfishness, feathering one’s own nest and nepotism, which of course are all geared to protecting one’s own kind.

Competitiveness and aggression in markets, behaviours that economists need to understand, are rooted in molecules found on the male Y chromosome and other gene loci that shape the human temperament. Of course, genes always interact with the environment, and some are not conducive to competitiveness.

Political science takes for granted the human tendency for war, organised aggression and genocide. But what is this tendency, what does it comes from, why is it still there? We create institutions to prevent war and conflict, to regulate a natural tendency that worsens, as populations grow larger and why is that?

The relationship between human density, disease and war is of critical importance to understanding population growth as it is to getting to grips with the real consequences of climate change. Human habitats will be profoundly shaped by weather patterns and water levels and, poorly managed, will become unprecedented incubators of conflict and war.

Understanding molecules is important for reconstructing ancestral populations and here we have the fast exploding discipline of molecular anthropology. Typically, anthropologists, who study pre-literate societies, rely on archaeologists (who study things left behind) and palaeontologists (bones left behind) to reconstruct people long gone.

Information from molecules like DNA contributes to reconstructing past societies, but it is important to grasp what it tells us and what it does not. It tells us the geographical origins of where our ancestors lived and moved to over long stretches of time, for some up to 100,000 or so years ago.

If we look at what is known as mitochondrial DNA (energy producing DNA molecules found in the cytoplasm of the cell) we are able to reconstruct female lineages of those of our maternal ancestors who had offspring. Both males and females carry the mitochondria, but only females hand them down.

If we look at the sex-determining male Y chromosome, we are able to reconstruct paternal ancestral lines. To therefore get a complete picture of one’s ancestry both the male and female lines require examination, though it is of course possible if not quite as interesting to test males only.

DNA testing of ancestral geographic origins is of course a blunt instrument. For example, it is possible to say that person X shares ancestors with present population living in North India and Southern Pakistan of some 60,000 years ago, but we cannot put names or identities to every person who was part of the cumulatively staggering 2,400 generations of descent!

We become more sophisticated and precise the more tests we do. The biggest global effort is the Genographic Project, a joint initiative of National Geographic and IBM, led by Spencer Wells. Visit their remarkable website www.genographic.com to learn about ancestral migration patterns.

The Living History Project is a joint initiative of the Africa Genome Education Institute (www.africagenome.com) and Ancestry24.com (www.ancestry24.com).