For the scientist, the technical development of biology cannot advance fast enough. Sometimes he feels like a blind man trying to feel an elephant with his hands – and instead of the trunk, thinks he has found a snake; instead of a leg, a tree. All the same, he has at his disposal the most state-ofthe- art measuring methods to answer his questions on the development of the human brain. “It’s like looking at things for the first time under a microscope that you’ve been able to examine before only with a magnifying glass,” enthuses the researcher. And he can’t wait for the day when he can swap his microscope for an electron microscope.
He also takes rather unusual routes in some of his analyses. For example, he is working with a research facility that, at first glance, has nothing to do with the human brain – the Max Planck Institute of Molecular Plant Physiology in Golm, where a new measuring method has been developed to determine how much oil and other metabolic products different plants produce – a method that can also be used just as effectively to measure the different molecules in brain samples, such as neurotransmitters or lipids.
Khaitovich receives vast amounts of data from the partner institutes, which must then be evaluated. “This requires students who are not only very talented, but who are also obsessed with their work,” says the molecular biologist, only half joking. Among the wealth of information, the scientists attempt to recognize biological signals – certain patterns in the data that indicate peculiarities in the development of the various species. “Sometimes we fail miserably,” Khaitovich admits. “And quite simply because there is no established procedure to point us in the right direction.”
The first results, however, are encouraging, although the data has not yet been fully evaluated. “We can already see very clear molecular differences between the brains of humans and apes.” One of the results confirms the old idea of neoteny – but only to some extent. According to this theory, the gene expression in the brain of a juvenile human is roughly equal to that of a chimpanzee a few years old. For several hereditary features, this is actually the case. “But for other genes, the picture is completely different,” says Khaitovich. His interim assessment: “The reality is much more complicated than we previously imagined.”
The young researchers can get closer to an answer only step by step, theory by theory. This is sometimes frustrating, not just for the scientist himself, but also for his mother in Moscow, who, says Philipp Khaitovich, is very interested in his research. So far, though, she has not been disappointed by the progress: “She believes that there are so many interesting things to find out about the brain and the longevity of humans,” says Khaitovich with a wide grin: “And she says that we are concentrating on far too small an area. But we’re really just a very small research group.”
Biologists talk about neoteny if plants or animals retain externally youthful features. In terms of humans, this could explain, for example, the lack of body hair and the long life. Accordingly, a human is a monkey whose development has been greatly retarded.
For some time, these were assumed to be cells in the brain that support the neurons, provide electrical insulation for one another, and provide nutrients. According to more recent findings, however, they also play an active role in the processing of nerve impulses (cf. MaxPlanckResearch 2/2006, page 42 ff.).
This substance forms predominantly the external brain tissue and is actually pink, although it turns gray in formalin. In it are the cytosomes of the neurons. The nerve fibers, in contrast, form the white matter that is found inside the brain tissue.