The language gene - FOXP 2
Man is clearly distinguished from other animal species, not by the
faculty of thought or intelligence, but by his capacity for language.
The two particularly striking features of human language are duality of
structure and creativity (open-endedness).
According to the first property human language has two levels primary
or syntactic level of analysis and a secondary or a phonological level
of analysis. Because of the species specific creativity the human beings
are capable of producing an innumerable number of new sentences (Lyons,
1977). There are several definitions of language.
The systematic, conventional use of sounds, signs or written symbols
in a human society for communication and self expression is language. An
artificially constructed system used to expound a conceptual area or to
facilitate communication; contrasts with natural language. (Crystal,
1998).
There is an argument as to the nature of human language, whether it
is a human endowment or whether it is a human accomplishment. It is
regarded as human species specific genetic endowment. It is uniquely
human and genetically unique. It is not found in other animals in its
present form. So it is also a generic accomplishment.
The genetic uniqueness of human language is easily explained by the
fact that children easily and quickly pick up language and develop it.
It is believed that the children are equipped with a Language
Acquisition Device (LAD) in their brains that is genetically programed
which directs the process of language learning whereby children infer
rules from the language data they are exposed to. (Widdowsson, 2000).
It was Chomsky’s claim that the human beings are equipped with a
specifically linguistic programe which is unique to the human species
and different in kind from any other capability.
In 2001 geneticists suspecting that language has some genetic basis
tracked it down to the gene FOXP2 - ‘the language gene’. Noting that
language is complex and characteristically a human trait, some
scientists believed that FOXP2 was essentially human and specific to
humans.
But versions of FOXP2 have been found to exist in many other species
of animals, ranging from birds to bats to bees and crocodiles and chimps
etc. But the human version of FOXP2 differs from that of the
chimpanzees, gorillas and rhesus macaques by two amino acids out of a
total of 715 and from that of the mice by three only.
It means that the human FOXP2 evolved recently and rapidly; only one
amino acid changed in the 130 million years since the mouse lineage
split from that of primates, but we have picked up two further
differences since we diverged from the chimps and this seems to have
happened only with the evolution of our own species at most 200,000
years ago (Nature, vol 418,p 869).
In a British family known as the K. E. Family, several members were
found to have language difficulties and it was found that there has been
a mutation in the human form of FOXP2 gene. (Young 2008).
According to Richard Klein, an anthropologist of Stanford University,
California, the human language gene FOXP 2 underwent a dramatic mutation
about 50,000 years ago that brought about the cultural great leap
forward”, which tipped humans over into modernity and equipped them with
creativity, skills and tools needed to conquer the rest of the world.
This caused the human beings to leave Africa and spread their
population over the entire globe. (Jones 2007)
All bird species have versions of FOXP2. In the zebra finch, its
protein is 98% identical to ours differing just by eight amino acids. It
is particularly active in the area X of the bird’s basal ganglia of its
brain which is involved in song learning.
It was found by inhibiting the activity of area X the song birds
found difficulties in developing new tunes. (PLos Biology, vol 5, pe
321).
FOXP2 has been found to exist in the extinct human species - the
Neanderthal man too. German anthropologists extracted DNA from the bones
of two Neanderthals.
They found that the Neanderthal showed the two mutations in their
FOXP2 gene akin to that of ours-mutations occurred since our lineage
split from chimps between six and five million years ago (New Scientist,
vol, 199,2008,p 40).
References
1. Crystal David (1998) The Penguin Dictionary of Language, 2nd
Edition
2. Lyons John 1977) Chomsky, William Collins Sons, London.
3. Widdowson H. G. (2000) Linguistics, Oxford University Press.
4. Jones Dan (2007) Going Global, New Scientist, 27 October 2007,
p36-41.
5. Young Ed (2008) More than words, New Scientist 16 August 2008
p38-41).
- Dr. Senarath Tennakoon |
