Can there be a Genetic reason for World Peace?
According to many a social scientist, we are living in the most peaceful time in the history of the world. Looking back over the past few decades, we see the Gulf wars, the wars in Iraq and Afghanistan and terrorist attacks on many major cities of the world but the fact remains that this bloodshed is much lower than the everyday violence in the lives of our ancestors. Cutting off body parts, death sentences, honour killings, all once acceptable punishments, are being increasingly condemned. The human race seems to be tending towards peace. Can we hold some genes responsible for this? This gradual movement towards peace, which we might term as a sort of tameness, can be comparable to domestication of wild animals. Wild animals, who are violent and aggressive, domesticate into friendly and docile creatures. Man was instrumental in taming; wild wolves into dogs and wild cattle into the ones which peacefully part with their milk and plough fields. How this transformation from wild to domestic occurs remains a mystery. A particularly interesting experiment was carried out by a Russian geneticist named Dmitry Belyaev. He tried replicating what man had done thousands of years ago, he tried domesticating animals. For his domestication experiment, Belyaev chose the fox. These foxes were screened and bred for their 'tamability', or the ability of these animals to be friendly with humans. Fox pups were tested for these qualities from their first month. The pups who would let the researchers stroke and feed them were selected over the ones which tried to bite or growl. By the 10th generation, 18 per cent of the tamer foxes were observed to be 'eager to establish human contact, whimpering to attract attention and sniffing and licking experimenters like dogs'. They were designated 'domestic elite'. In the 30th-35th generation today, about 70-80 per cent of these foxes are 'domestic elites'. Some are even up for adoption as pets. Apart from their behaviour, many physical changes were observed in these foxes. There was loss of colour in certain parts of the body, some had developed a star-shaped mark on the forehead. Other changes included features which we see commonly in dogs like curled tails and floppy ears. The level of corticosteroids, responsible for the fear or fight/flight response was considerably lower in the domesticated foxes. These phenomena are common to most domestic animals. This rapid change in physical characters which makes these foxes distinct from their forefathers seems to go against Darwin's notion that speciation or the formation a new species takes thousands of years. The mystery begins to thicken. Scientists have considered multiple causes for these rapid physical changes. Expression of particular recessive genes conferring these 'domestic' characters was the first guess. But, during Belyaev's experiment, great care was taken to avoid excessive inbreeding which could result in any recessive gene showing its effect. Another reason is thought to be polygenes i.e. a complex system of genes which codes for these traits might be responsible for the changes. However, polygenes are very delicately balanced systems. Even a slight change in one of the component genes could lead to detrimental effects on other vital processes of the animal; this does not seem to be the case in domesticated animals. The most fascinating explanation might be that of heterochrony. Heterochrony is the hastening or delay of the events which occur during development. Development of an organism occurs after the fusion of two cells - the ovum and the sperm, to form a zygote. This zygote undergoes multiple divisions to give rise to the multicellular structure viz. the organism, through a regulated and time-bound process. Many different transient structures are formed during development, which later give rise to various organ systems. A rather interesting one is the neural crest. Neural crest cells originate from early neural tissue and migrate across the embryo.
Dr. Mariana Delfino, from Universidad Pablo de Olavide, Seville, Spain, elaborates, "[the neural crest cells] gradually delaminate and they begin to migrate throughout the body using stereotyped pathways in order to reach specific locations where they can differentiate to new tissues." These cells give rise to various organs in body. "Neural crest cells begin as a multipotent cell population but gradually differentiate into very specific cell types." The different tissues neural crest cells are responsible for like the skin colour, cartilage, adrenal glands are some of those which are affected during domestication. Domestic animals show decreased skin pigmentation or spots. Ear cartilage which makes the ears stand erect is reduced in domestic animals making their ears floppy. Low levels of adrenaline, the hormone responsible for the flight or fight reaction, makes domestic animals less aggressive. Adrenaline is produced by adrenal gland; again a derivative of neural crest. Dr. Delfino mentions that, "Deficiencies in neural crest migration as a result of mutations in relevant genes can have widespread effects in embryonic development as cells do not reach their appropriate positions or do so at inappropriate time points". Can such discrepancies in the timings of neural crest cell migration be causing all the changes from wild to domestic? Timing seems to be the key. Mutations in these 'time-keeping' genes are possible targets for further study of domestication. These questions are yet unanswered. The experiment started by Belyaev in 1950s still continues. As in the foxes, lower levels of adrenaline than the past generations might be cause for dulling our instinct to fight. If this 'human domestication' continues, our quest for 'world peace' might not be just a fantasy.
Published on Apr 19, 2010