Chinese scientists have identified a unique gene variant linked with learning and memory, which may help understand how humans acquired intellect and language skills much faster than their closest relatives, monkeys.
Researcher Bing Su and his colleagues at the Kunming Institute of Zoology say that the KLK8 gene makes the neuropsin II protein, which has been found to be vital for memory and learning in mice.
In their previous works, the researchers had shown that the neuropsin II is made by humans but not by lesser apes and old-world monkeys. Their present study proves that even orang-utans and chimpanzees do not produce it.
According to the investigators, KLK8 is the first human-specific discovery of a "splice variant", a gene that is roughly the same in different species but is "cut and pasted" differently when it is expressed, resulting in proteins with new functions.
Their study shows that the gene arose through a single mutation in the DNA, when a thymine nucleotide was exchanged for an adenine, causing 45 additional amino acids to be loaded into the protein that the gene expresses.
Boffins say that the changes make humans' neuropsin II significantly different from the neuropsin made by other mammals.
"It would be extremely exciting if the new form [of neuropsin] enhances learning and memory," the New Scientist quoted evolutionary biologist Jianzhi Zhang of the University of Michigan, as saying.