Genetic engineering, being a direct manipulation of a living organism's genes, have advanced as it has faced many ethical issues.

Just recently, a group of Chinese scientists has implanted human brain genes into 11 rhesus monkeys. The study, as the team explains, is intended to provide a different perspective on the evolution of human intelligence.

Human versions of the MCPH1 gene was used in the study. The said gene is supposedly in control when it comes to human brain development.

In their study, the rhesus monkeys were found to have taken a longer period in brain development, much like humans. The subject monkeys were also said to have performed in tests better than the unmodified subjects. The tests, focusing on short-term memory and reaction time, have resulted in five monkeys doing well and getting a passing mark. The memory test entails remembering colors and shapes on a screen. Later, the subject monkeys were given MRI scans.

This test done by China has yet again fueled debates on ethics as with their previous biomedical experiment. The ethical concerns have risen because of comparisons with "Planet of the Apes," a dystopian sci-fi film.

The research was conducted by a team at the Kunming Institute of Zoology and the Chinese Academy of Sciences. They are working in collaboration with a team of US researchers from the University of North Carolina.

Jacqueline Glover, a University of Colorado bioethicist, was among those who questioned the ethics of the experiment even if the research authors have pointed out that rhesus monkeys are distant enough to alleviate any ethical concerns. It still stands that the subject monkeys are closer to human than they are to rodents. To which, Glover pointed out that humanizing the subject monkeys will cause them harm, especially regarding their habitation and traits.

One of the researchers for Genomic Sciences at Hong Kong University, Larry Baum, explained that the differences between the genome of rhesus monkeys from that of humans are by a few percents only, which is actually millions of DNA bases that differ between humans and monkeys. This means that only one if 20,000 genes would have been modified.

Baum pointed out that through the study, they now have evidence that supports the concept that slower maturity of brain cells could be one of the factors that can be used in improving intelligence during the process of human evolution.

Early this year, another team of Chinese scientists has cloned a single macaque to create five more.