Why do giraffes have long necks? It is a question your five year old may ask. Do not take it lightly for it’s a very serious question – about heredity and evolution, about the interplay of our genes and the environment we live in.
According to Jean-Baptiste Lamarck (1744-1829), giraffes acquired their long necks because their recent ancestors had stretched to reach high, nutrient-rich leaves. Charles Darwin, younger and smarter, had a different answer in his Origin of Species, 1859: giraffes got their long necks because genes for long necks had, very slowly, gained advantage. In other words, long necks came to be by way of evolution over millennia through impartial, natural selection.The Darwinian view held sway.
All through human history we have recognized that parents transmit, through nature, some ‘likeness’ to their children, who will then pass it onto their children, and so on. But scientists are never satisfied with somehow, something. So thequestion was,what andhow? In the sixth century B.C. Pythagoras theorized that male semen conveyed the full information into female bodies, which merely provided the necessary nourishment for nine months. Two hundred years later, Aristotle built on it to say that both men and women contributed to transmitting the ‘likeness’. After that, for 2 millennia, silence! H.G. Wells, writing a little over 100 years ago, referred to heredity as the ‘missing science’.
This missing science is now called Genetics and the essential building block,was called the gene. It comes from the Greek root, ‘geno’, meaning ‘to become or produce’. We know today that genes are made up of deoxyribonucleic acid (DNA), a molecule that carries the genetic instructions to build a protein, which creates form and function in the human body, which in turn regulates the gene. It encapsulates the endless circle of life:growth, development, functioning and reproduction of all known living organisms. Scientists have, now, isolated and counted the genes in our bodies: it takes 21,000 to 23,000 to make a human being.
It is important to remember, however, that genes function in an environmental context,good or bad, of external triggers and stimuli. It consists of the psycho-socio-physical milieu the child grows up in, provided by the parents and the society at large. Developmental inputs and experiences in the early years have a particularly formative influence. Let us take ‘intelligence’ or IQ as a case in point – am I born smart or do my experiences shape me?A father’s claim – my children are smart because I am – will sound familiar. He may add, as an afterthought, that the mother’s upbringing had something to do with it too!
To separate the influence of genes and environment on the trait of intelligence,Francis Galton (1822-1911) – a half cousin of Darwin and a child prodigy by many accounts –made the first social scientific attempt to study the primary driver of ‘genius and greatness’. He attributed his own “intelligence” to his genetic heritage. He could not bear the thought that his life of privilege and opportunity had anything to do with it.In his vastly acclaimed, The Gene, Dr. Sidhhartha Mukherjee,Professor of Medicine at Columbia University, puts it lucidly: ‘Intelligence … is heritable (i.e., influenced by genes), but not easily inheritable (i.e., moved down intact from one generation to the next)’.
The answer,therefore, to questions of what makes us who we are,lies in the dynamic interplay of nature and nurture. The last few decades have seen the birth of epigenetics: the study of ‘markers’that are imprinted on our genes, as a result of environmental factors like diet, trauma, stress and prenatal nutrition, that tell our genes to switch on or off, to be aggressive or passive.The ‘versus’ in the 'nature versus nurture'debate – a phrase coined by Dalton –stands debunked now.
We have talked in other posts about how deprivation – of nutrition, cognitive stimulation and emotional nurture – can lead to learning and health deficits in a child, with long-term consequences for his/her wellness as an adult. There is an increasing amount of data, for instance, that suggests that growing up poor has long-term effects on people. If scientists compare the epigenome (markers superimposed on the genome) of a person who grew up in poverty but managed to reach a high socioeconomic status later in life,to that of someone who was born into and continued to retain the high socioeconomic status, they’ll find that their epigenetic states are different. Poverty seems to have consequences that produce effects that can be detected in the body decades later.
It seems that in between the wide spectrum of genetically determined eye colour and environmentally determined native language, lies the grey area, where nature interacts with nurture. While extreme deprivation can nullify a good gene, a good dose of motherly love can tweak the stress gene in children to help them cope better as adults.
Thus, building a better understanding on how to nurture the inherent potential in a person assumes significance. Governments, schools, neighbourhoods and families can influence the quality of nurturance for a child. Raising standards and understanding the needs of children of different age groups are ways to achieve this.
It is a big responsibility, but nurturing childhood was never just child’s play.
Richard Dawkins, “The Selfish Gene”, 1976
Matt Ridley, “Nature via Nurture: Genes, Experience, and What Makes Us Human”, Harper Collins, 2003
Siddhartha Mukherjee, “The Gene – An Intimate History”, Penguin Allen Lane, 2016