The Rat People of Pakistan

Jihadist Islam is producing western examination of all aspects of the existing religious culture and one unusual story explores what are termed the “rat people” of Pakistan. The British online newspaper Telegraph has details about the strange phenomenon of retarded children with very small heads and what the defect may indicate about all of us.

What makes us human? The word "microcephaly" comes from the Greek, "small head". But in Pakistan, such children are known as chuas or "rat people". … it was common enough to attract the attention of Geoff Woods, a geneticist working at Leeds University. He found that it ran in families. That implied that its cause was genetic; it was caused by a mutation. Or, more precisely, several. By the late 1990s, the disorder had been mapped to deficiencies in at least six different genes. ... All seem to encode proteins that are needed if neuroblasts - the cells that give rise to the brain's neurons - are to divide and prosper.

The interesting part is that only the cerebral cortex in the brain appears to be effected in what is now more specifically identified as autosomal recessive primary microcephaly (MCPH). Afflicted individuals are otherwise completely healthy and normal except for the small heads and a stable retardation present from birth. The abnormality appears to require defective genes from both parents, so it is a recessive trait which would remain rare except in unique circumstances. In Islamic Pakistan, the high frequency of this rare disorder appears to be driven by customs in which “some 60 per cent of marriages are between first cousins”.

The research team lead by Dr Geoff Woods believe their work may help explain how humans became human at a genetic level. Again from the Telegraph article:

In the last three million or so years, the human brain has approximately trebled in size. This change, remarkable in its extent and speed, must have been caused by mutations - advantageous mutations - that swept through the populations of our ancestors as they wandered, generation after generation, across the African veldt. … Chimps and humans each have about three billion nucleotides in their genomes - 99 per cent of those may be identical, but that still leaves about 30 million differences.

If what makes humans different from animals is the size and function of our brain, then as few as a dozen genes may be responsible for the biochemical instructions yielding the structural reason why we emerged as a unique species.