A comparative study of gene activity in the brains of humans, chimpanzees and other apes reveals some interesting differences in the way certain genes are expressed * The interesting part is when did our genetic code and that of the chimpanzees separate?
Prof. Sawant Pavo (left) and one of his research subjects
Comparison of chimpanzee and human genome segments sheds new light on the question of why these two species are so different despite having a very similar genetic code. Scientists have been discussing for a long time the question of what makes humans so different from the closest carnivores to them - the great apes.
One of the lead scientists on the project says the answer lies in the process orchestrating the genes as the chimp evolved. The human genome and that of the chimpanzee differ by approximately 1.2 percent in the genetic code.
Prof. Sawant Paabo from the Max Planck Institute in Leipzig, Germany, investigates which genes are present and how they are expressed.
CHIMP DNA – PAN TROGLODYTES
The genome of the chimpanzee - facts
There are 3.1 billion base pairs (pairs containing two of the four enzymes adenine, thymine, cytosine and guanine, which are found in 25 identifiable groups - chromosomes. Apparently in this DNA script are hidden 25-30 thousand genes that chimpanzee cells use as a basis for creating proteins. These recalcitrant molecules are used to build and maintain the animal's body.
In particular, he believes that the key lies in the degree to which these genes are expressed in each species of animal. "In abstraction it is possible to say which genes are turned on, and where they are expressed in the brain."
"We systematically tested gene activity in the brains of chimpanzees, humans, orangutans and macaque monkeys and compared them. The surprising finding is that we found quite large differences. In any given part of the brain, About 10 percent of our brain activity is different from that of chimpanzees," said Dr. Pabo.
The key to the difference between the two sexes may lie in the functional importance of different levels of gene expression. Using a mathematical model, in which the change in gene expression between any two species will be illustrated, Pabo hopes to identify those genes that might have been prioritized in the process of natural selection more strongly than others.
There are small but important differences between individual genes. So far, Dr. Pabo and his team have found two small but important differences in the FoxP2 gene that are believed to be responsible for speech and language skills.
Chimpanzees also have a more developed sense of smell than ours, and so unsurprisingly, there are also differences in genes related to smell. "The genes related to our sense of smell code for the receptors in our nose, and we found that in the process of evolution we lost a large part of them and became very bad at smelling, Pabo said.
"Therefore it seems that as our language ability improved, our sense of smell deteriorated. The other genes are those that have been positively selected for language and speech and they joined in the last 200 years or so.
More such differences may be found as groups of scientists around the world begin to make direct comparisons. In particular, the Human Genome Group at the Sanger Institute in Cambridge wonders why chimpanzees are vaccinated against many human diseases, such as malaria and AIDS. says Dr. Tim Hubbard Hubbard.
By closely studying the differences in genetic diseases between chimpanzees and humans we can gain a better understanding of the disease process which may in turn lead to the development of better drugs.
