2/21/2009

Happy Birthday Mr. Darwin!!!


On february 12th, 1809 Charles Darwin was born, and so was Abraham Lincoln, the former in Shrewsbury-England, ans the latter in Spring Farm, Ketucky-USA. They both had significant work and imprtance in World History in the case of Darwin; and US History in the case of Lincoln.
But let's focus on Darwin. I was fascinated by his theory when I started reading about it, and even though many scientists have tried to prove him right or wrong, it is undeniable that his theory clarified the way we approached to changes of living organisms. This comment is like a double-edge sword because Charles Darwin's ideas have been criticized and disputed since the publication of The Origin of Species, his masterpiece. And even though it is the book that marked his evolutionary theory, he only mentions the term Evolution only once in his book.
Many have psychiologically analyzed Charles Darwin's ideas, work and life in general. Most of his work was a direct and indirect influence of his grandfather Erasmus Darwin, nothing less than one of the leading minds in the 19th century England.
Darwinists and NeoDarwinists, such as Richard Dawkins (The Selfish Gene) and Stephen Jay Gould (Ontogeny and Phylogeny) have had a hard work critizicing but maintaining Charles Darwin's ideas fresh, current and far from any expiration date.
I recommend to see the series of Darwin's life as part of an english production.. There are also a good number of video lectures by Standford University. Check them out.
Of course, speaking of evolution and Darwin I just cannot let pass the new concept in evolution mentioned by Juan Enriquez in his 2009 TED lecture, the Homo Evolutis. this is a very current, dynamic and entertaining presentation of today's crisis reality, robotics, scientific advances and evolution.




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2/08/2009

Such a Degenerate!!!


Don't worry, I'm not going to talk about the 90,000 sex offenders kicked out of MySpace. I'm actually going to mention something that puzzled me when I was in my undergrad years. The Degenerated Genetic Code.
Our genetic code, or set of instructions coded in the DNA, is what alllows each cell in our body to synthesize proteins. Proteins are molecules of life formed by a chain of aminoacids that acquire a specific shape and function by folding its components into intricate 3d structures.
DNA (Deoxyribonucleic acid) is composed of nucleotides, or genetic "letters": A (Adenine), T(Thymine), C(Cytosine), G(Guanine). Three of these letters together form a codon (triplet), or "genetic word". The meaning of each of those words is an aminoacid. When a long string of "genetic words" are read, a long chain of aminoacids is produced. This is done making a usable copy of DNA, called RNA (Ribonucleic Acid), a template made from DNA that can be read and then destroyed. The differences between DNA and RNA are: DNA is a double chain molecule, whereas RNA is a single chain molecule. DNA contains the nucleotides: A, T, C, G. in RNA, the nucleotides are: A, C, G and U (Uracil). Uracil replaces T in RNA.
It was well known that the positioning of each genetic letter (A, T, C, G) in the triplet or codon, would determine a different type of aminoacid. However, it had been found that when the first two letter positions remained constant, and only the third letter was changed, it could be observed that the aminoacid produced was the same. This is called Degenration of the Genetic Code.
However when the first or second letters were replaced or changed, a different aminoacid was produced, and the resulting protein usually was defective, or misfolded, useless for its original purpose in any case.
This is something like genetic synonimity, if the term can hold the analogy. Because more than one triplet could "mean" or produce the same aminoacid.
I just came across a report from the American Journal of Human Genetics that takes this degeneration to a research study that found that 1 in 200 genes can be superfluous or dispensable.
Here is the link to the article, take a look at it.

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