A joint team from South Korea and Japan has deciphered the Y chromosome of the chimpanzee genetic code in a major step towards unraveling the mystery surrounding human evolution.

The Korea Research Institute of Bioscience and Biotechnology on Monday said the team has decoded more than half of the 23 million Y chromosome bases of chimpanzees with the Genomic Sciences Center of Japan's Institute of Chemical and Research.

Senior researcher Park Hong-seog said the discovery is a major advance in the study of changes in the genetic structures of humans and chimpanzees and the evolutionary process.

Another researcher said he expects the findings to provide the basis for academic and medical development by eventually leading to a complete understanding of human genetic structure.

The discovery was published in the January 1st edition of the international journal Nature Genetics.