Science & Self-improvement

The spaces between the genes have proved to be important in explaining the vast differences found between apes and humans. Rather surprisingly, non-coding sequences of DNA make up more than 90 percent of the human genome. Reciently, scientists have discovered that they contain elements than can control how and when nearby genes are activated.

An international team led by genome researcher Edward Rubin of the Lawrence Berkeley National Laboratory in California wonders if these non-coding regions play a role in human evolution. They looked at more than 100,000 samples of non-coding DNA sequences that seem have been conserved during evolution. Statistical tests proved that almost one thousand sequences were not due to simple chance, suggesting that they were caused by natural selection.

The strongest evidence was found in sequences next to genes involved in helping the neurons to keep together. These sequences may have contributed to the evolution of uniquely human cognitive talents. Rubin says that neuronal adhesion molecules play an important role in “wiring” the brain. The formation of connective synapses between nerve cells is involved in these processes, which are crucial in early brain development, as also in adult learning, memory, and cognition.

A molecular biologist at the University of California, Ajit Varki, says that the conclusions sound interesting and plausible, but cautions that the findings should be considered tentative because the gene databases that were used give only a broad generalization about a gene’s function.

Science, 3 November 2006

The first modern humans, known as the Aurignacian culture, moved westward across Europe some 40,000 years ago. The European territory was then occupied, as far as humans ancestors concern, by the species known as the Neanderthal man or Neanderthals for short. They inhabited from Iberia and Britain to Israel and Uzbekistan. They had do so for about 400,000 years, but 10,000 years after encountering the Aurignacians they had practically disappeared. Their last refuge was the Iberian Peninsula, where now are Spain and Portugal.

What happened in this encounter between two cultures is still unknown. One hypothesis is that the Neanderthals were eradicated by the Aurignacians, who had superior arms. The Neanderthals were armed with old-style stone weapons that were much older than those of the Aurignacians. Another hypothesis is that both species interbred, and that some characteristics of the Neanderthals were incorporated to the genetic pool of the human race.

To answer this question and others related to the Neanderthals and their extinction, one method being attempted is the analysis (or “sequencing”) of DNA molecules taken from fossil bones. As it is known, DNA studies help to find the genetic relation between two people or two species. For example, they have demonstrated that the living species most similar to the man is the chimpanzee. However, the study of DNA samples taken from old bones was at a time discredited due to extravagant claims of having recovered DNA from dinosaurs dead millions of years ago.

Enhancements in the field have made scientists more confident in this type of studies, and recently an attempt was initiated with DNA extracted from a Neanderthal’s femur found in the Vindija Cave, in Croatia. Two teams, one at the United States and another at Germany, have worked independently and using different methods. At the Joint Genome Institute in Walnut Creek, California, used a method call ‘metagenomics,’ in which the fragments of genetic material are incorporated into bacteria that then copy the fragments. The other team, working at the Max Planck Institute for Evolutionary Anthropology in Leipzig, use the method known as direct sequencing.

While the work is still under course, results up to the moment confirm the difference between the human and the Neanderthal genomes. A rough draft of the full Neanderthal genome is expected to be produced over the next two years. This genome is expected to reveal many distinctive qualities of the Neanderthals, e.g., whether they spoke, the color of their hair and their skin. It has been advanced that the mating theory is now considered very much unlikely, although it cannot still be excluded.

The question about if the Neanderthals spoke or not could be solved looking at the form of a gene that is related to the development of language skills. The color of the hair and the skin can be deduced by examining genes involved in these somatic characteristics. However, even if they are our closest evolutionary relatives from which we diverge some 500,000 years ago, Neanderthals will continue to be something of a mystery until more extensive DNA sequencing is done.

See also:

Creationism and Evolution

Genetics

One cannot but wonder if the brains of geniuses are somewhat different from that of us ordinary people. Obviously this is a difficult question to answer by several reasons: people are not usually prone to leave their brains for scientific study, many geniuses were dead before neurological studies were initiated, etc. There is, however, one outstanding case in which such a brain could be studied: the brain of Albert Einstein.

When Einstein died in 1955, he was universally recognized as one of the greatest geniuses that humanity had had. At that time, he was working at the University of Princeton. The then pathologist at the Princeton hospital was Dr. Thomas Harvey, who stole the brain and lost his job as a result. In 1995 Dr. Harvey sent a fax to a neuroscientist, offering her the possibility of study Einstein’s brain. The offer was of course readily accepted.

Harvey had rejected most of the requests for Einstein’s brain that he received from neuroscientists. The scientist that Harvey had chosen in this case to give an opportunity was Dr. Sandra Witelson, who works at the School of Medicine of McMaster University in Canada. There, Dr. Witelson has a collection of 125 brains, all of Canadian people, that she keeps in a walk-in refrigerator. By analyzing the weight, the volume, and the proportions of her specimens, Witelson investigates the relationship between brain structure and cognition, which has been the subject of her research for thirty years.

Witelson’s study of Einstein’s brain in 1999 revealed some features that had been overlooked by other researchers: the parietal lobe was fifteen percent larger than average, and it was a single compartment instead of the usual two ones. Histological studies of Einstein’s brain are underway, in order to determine features such as the packing density of his neurons.

Witelson has also for study the brain of the mathematician Dr. Donald Coxeter, a distinguished geometer that died at 96 and that remained intellectually active almost to the end of his life. A vegetarian who rarely drank alcohol, and preserved physical fitness, Coxeter had the brain of a much younger person, says Witelson. In his case, as in Einstein’s, the parietal lobe was larger than normal.

While many studies have been done about damaged brains, the brains in Witelson’s collection are of normal people without brain damage. The brain bank was initiated as part of a study to find why language capacity is located in the left hemisphere of the majority of people. People of all kinds that where to die as a result of cancer were sought to be donors, and extensive testing was carried on while they were still alive.

While her research has yet to answer many questions about lateralization of language capacity, interesting results on the differences between male and female brains have been shown. After a ten-year study, Witelson published findings showing that the packing density of neurons is 12 percent greater in the female brain than in the male brain in the region where the language capacity is located: the temporal lobe. A similar difference was found in the frontal lobes.

While these differences could be attributed to the known fact that female brains are generally smaller than male ones, Witelson says that it would be not correct to do so because the difference in packing appears only in some layers of the cortex. These layers are the important ones in processing information input. The question to answer now, says she, is if the processing of speech sounds could be related to the anatomy of the brain.

Scientific knowledge is acquired by means of the scientific method. When one first meets this expression, one is likely to be deceived by its simplicity. “Scientific method” doesn’t look very impressive, and one may ask if there is much to talk about it. We are in the habit of hearing important things called by important names, and this name seems rather humble. However, this is the case where an important thing is disguised under a very common name.

Our present world would not be the same without the scientific method, as it is the base of science. It was fostered by two 17th-century movements called “rationalism” and “empiricism.” That century–when Galileo, Harvey, Newton, and Boyle were alive–beheld for the first time a departing from the idea that knowledge about the world should be received from an authority. The scientific method was discovered in this century, but there were disagreements as to how it should be applied.

Rationalism was a philosophical school that contended that fundamental knowledge is based on reason and that truth is found by the rational analysis of ideas independently of emotions or authoritative pronouncements. Rationalism can be symbolized in the figure of Rene Descartes who, in the Discourse on Method, asserted that all theoretical science should be like Euclidean geometry.

Empiricism, on the other hand, sustained that legitimate knowledge aroused from what is provided to the mind by the senses. Empiricist did not consider knowledge what is gained through imagination, authority, tradition, or mere reasoning. Empiricism can be symbolized by the figure of Francis Bacon, who in his work Novum Organum proposed that the laws of nature should be obtained by applying inductive reasoning to observed facts.

According with current views, neither of these two positions is entirely right, but both must be used according to the situation. Neither pure rationalism nor pure empiricism could have achieved what science has achieved. Wrong results can be obtained applying any of the two methods. The best result is when each method is used to control the other one, that is, when reason controls what is perceived by the senses, and what reason deduces is contrasted with experimental facts.

Deviations from this norm–the harmonic playing of reasoning and experience–can lead to disaster particularly in the social sciences: anthropology, psychology, and sociology. In these sciences the experimental work that is routinely carried out in the physical sciences is very difficult to perform for obvious reasons. Therefore, much of research is done by applying great quantities of reasoning to very few experimental facts. It comes as no surprise that theories abound and that some are later discredited. Most cannot be proved or disproved because the only way to do either thing is by means of experimental work that has not been done or cannot be done.

An outstanding case of a theory that was based mostly in the intuition (or reasoning) of its creator rather than in actual experimentation is psychoanalysis. The great pioneer work of Freud was based in clinical work carried out only by himself and in the deductions he made about what he observed in his patients. The scientific method as is now conceived-posing a hypothesis and proving or disproving it by experimentation-was completely absent in Freud’s research. Many of his results are nowadays forgotten, although the core of his theory still remains.

In 2005 Tenzin Gyatso, the Dalai Lama, gave a lecture at a meeting of the Society for Neuroscience in Washington, D.C. In that occasion, he suggested a healthy dose of skepticism toward religious pronouncements. Science can overturn spiritual teachings, he said, but people can benefit from scientific understanding without losing faith. This is important because in the United States of America it is still been fought a battle between those that want to put in practice a religion-free science education and those fundamentalist Christians that refuse to accept the theory of evolution because it threatens their beliefs. The conference was attended by nearly 14,000 people, most of them watching TV screens in other rooms.

The Dalai Lama also emphasized that religion can help science, not just hinder it. He urged neuroscientists not to discount the role of Buddhist traditions on the brain, specifically meditation. The neuroscientists in the auditorium responded with approval, especially those who have examined the effects of meditation. Bruce F. O’Hara, of the University of Kentucky, has found that meditation improves the performance of sleep-deprived individuals about as much as drinking a cup of coffee does. Olivia Carter, of Harvard University, works on meditation’s effect on perception. She said that it should not matter that the observations associated with meditation arise through introspection or contemplation, as long as the observations can be used to generate objective testable predictions.

Sara W. Lazar of Harvard Medical School remarks that not all scientists are equally as open to testing Buddhist meditation practices. She encountered mainstream scientists who do not meditate but are very curious and open, and other ones who are still unwilling to even consider the possibility that meditation might have some positive effects. Lazar has found that meditation may help prevent the rate of cortical thinning with age. Brain scans show that as people get older, the white matter typically degenerates. This material envelops the neurons and helps them work more efficiently. Lazar discovered that older people that meditate have active cortical regions that are comparable to those of younger people that do not meditate.

Such a discovery should not have been too surprising, according to neuroscientist Michael Merzenich of the University of California, San Francisco. He explains that the brain typically responds to repetitive use by thickening the cortex in the relevant area–for example, people who play the piano have more cortex associated with that skill. Recent studies, he says, indicate that changes produced by mental exercises in many respects parallel those produced by actual exercise.

Merzenich finds intriguing the idea of science studying the influence of faith on the brain. Images of the brain have shown that an area in the frontal cortex is activated in response to how strongly someone believes an answer to be correct. Merzenich presumes that this activation reflects the brain’s decision that one’s conclusion is correct, whether it is or not. This kind of findings reinforces what the Dalai Lama says about the importance on maintaining an open mind concerning the relationship between science and religion.