A new study in human evolution has pointed to sugar as one of the key ingredients that made the difference between man and his evolutionary cousin, the ape.

According to the study which was reported in ABC News, for millions of years, the common ancestor of humans and apes shared a specific kind of sugar. Apes and chimps still have that type of sugar, but around three million years ago human ancestors substituted a slightly different sugar, according to the researchers.

Around that time human predecessors become predators with preference for red meat. However, even with greater exposure to deadly pathogens, they seemed to have developed immunity from diseases of animal meat that they were eating.

According to scientists at the University of California, San Diego, who researched on this evolution theory that focused on the presence of a specific kind of sugar, the slight difference in sugar came about because of the mutation of a gene that is found in modern humans but not in apes.

This gene that caused the production of the sugar found on cells mutated about 6 to 7 million years ago after man's ancestor first stood upright, and when their brains began to increase in size.

Fossilized samples were collected from all over the world by a team led by Ajit Varki, a medical professor, to see if they could find out when the mutation occurred. They found evidence of the mutated gene more in Neanderthals. Their conclusion, which they published in the Proceedings of the National Academy of Sciences, was that the mutation could have probably happened around three million years ago.

Homo erectus, the most probable ancestor of humans could have emerged about this time, the study revealed.
The theory of the researchers is that the malaria caused the mutation to happen. At the time when human ancestors became hunters, the sugar switch happened which made them immune to the parasite that caused malaria in apes. This new sugar, however, made man's ancestors vulnerable to a different malaria parasite.

In this study, evolutionary biologist Pascal Gagneux revealed that at about the same time when man's predecessor started eating red meat, a major source of Neu5Gc (the sugar found on the cells of apes, but not humans) which may have further stimulated the immune response, adding that it became viewed by their immune systems as foreign and must be destroyed.

The study concluded that the immune mechanism that could have been developed was related to the origin of the genus Homo.