One Gene = One Protein? Not Even Close! – Proslogion
Central dogma and the genetic code. How does a gene in your DNA provide instructions for building a protein? In gene expression, a DNA sequence is first copied to make an RNA molecule, which is then "decoded" to build a protein. Read 3 answers by scientists with 2 recommendations from their colleagues to the question asked by Suliman Abdalla.I Ali on Dec 9, We now know that one gene can produce many different proteins, depending on with an imagined set of well-defined syntactical relationships could have led.
As a result, a single gene can actually produce many different proteins. The introns not only serve as a means by which the cell can identify the exons, they also regulate the amount of the various proteins that are being made. This process of alternative splicing is illustrated in the figure below: Because of alternative splicing, a single gene can tell the cell to produce different proteins.
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- Logic, DNA, and Poetry
However, I did not address how many different proteins a single gene can produce using alternative splicing. In some cases, the answer is truly astounding. Over the past couple of years, I have been helping the head of the biology department at a Christian university as he works with three other creation scientists on a university-level general biology textbook.
The last time we met, he made me aware of two papers that were written quite some time ago on the subject of alternative splicing. They specifically address the question of how many different proteins can be made from a single gene. The first one was written by Douglas L. Black and published in the journal Neuron. It reviewed some recent results on alternative splicing in a specific chicken gene.
The gene, which is called cSlo, is involved in hearing. One end of the cochlea contains hair cells that respond best to low-frequency sounds, and the other end holds the hair cells that respond best to high-frequency sounds. In between, the hair cells vary smoothly so as to respond best to the sound frequencies in between. The proteins produced by the cSlo gene aid in that process. Well, recent studies show that the cSlo gene uses alternative splicing to create different proteins, each with a slightly different electrical response.
As a result, when researchers studied the hair cells on one end of the cochlea, they found one of the proteins. When they looked at the hair cells on the other end, they found another protein.
In between, they found other proteins, each of which was ideal for producing a strong response to a specific sound frequency! Most are polygenic, which means they are brought about by cominations of many different genes; and just to stir the pot a little more — most genes are pleiotropic, which means that they affect more than one character, often characters that seem quite unrelated to one another.
Oh, we keep up… But what could I do then in life when so ignored, but become Abbott, look after my brother monks, eat good food and try to fight the monastery tax - but still I dreamt of fuschias, bees; and, yes, peas!
In the early nineteenth century John Dalton had proved that water was actually made up of billions of hard, irreducible little things called atoms and had defeated rival continuity theorists.
So now Mendel had proved the atomic theory of biology. The atoms of biology might have been called all sorts of things; among the names used in the first years of this [Twentieth] century were factor, gemmule, plastidule, pangene, biophor, id and idant. The British biologist, J.
Central dogma (DNA to RNA to protein)
Thus, we have come to relate genes to attributes such as wrinkliness or hairy ears. In these cases, there appeared to be a one-to-one relationship between a gene and a characteristic. As more and more information on genes emerged, it became clear that simple one-to-one relationships were exceptional. It is quite usual, for instance, for more than one gene to lead to a given trait.
A-DNA/RNA Poem - Bio1Bokeefecastelberg
Alternatively, genes may need to act in combination before a particular character shows through. Furthermore, environmental factors may influence the trait, sometimes dominating genetic factors.
Expression of principle, grasping partially hidden meaning, unlikeliness of such simplicity for burden of life, bright reality; history, present, future — factual organic magic to be uncovered, described, tested to carry this fabulous weight; this holy script for eye and wing, panda, peacock - prescription for luminosity.
They proposed a law of biology, which caught on and has proved to be more or less correct: Geneticists began to chant it under their breath: It has first been isolated, from the pus-soaked bandages of wounded soliders Their chemistry was now known more correctly and moreover, the tetranucleotide hypothesis was dead, killed by some very beautiful work by a chemist at Columia, the Austrian refugee Erwin Chargaff.
DNA was known to be a polymer, but with a very different backbone and with only four letters in its alphabet, rather than Chargaff showed that DNA from different sources had different amounts of these four bases as they were called. Perhaps DNA ws not such a dumb molecule after all. It might conceivably be long enough and varied enough to carry some genetic information.
He must have seemed an unlikely solution to the gene problem, but the solution he was…Watson developed an obsessive conviction that genes were made of DNA, not protein…Chance threw him together with a mind of equal brilliance captivated by the same conviction about the importance of DNA, Francis Crick. But they had not.
All was suddenly clear: DNA contained a code written aliong the length of an elegant, intertwined staircase of a double helix, of potentially infinite length.
That code copied iteself by means of chemical affinities between its letters and spelt out the recipes for proteins…The stunning significance of the structure of DNA was how simple it made everything seem and yet how beautiful. The Autobiography of a Species in 23 Chapters, Fourth Estate, There can be no understanding of genetics without beauty; power, structure, aesthetic, are one. The identity of DNA; in operation, its shape, principle - evolving silver spirals as consist the living world - hallmark of life, are beautiful in themselves, as well as genius chemistry; weeping talent - ultimate creativity with so few chemicals; so drawn from nothing.
Electrical nexus to a living script, somehow pre-existent to itself and all its products - suggesting mind, power, force, some living principle where life is expanded beyond our mortal and immortal sense to some first agency, desire for life among blank Universe - invention of life from energy, idea, creative circumstances among the heavens; an explosive concept.
For decades, it has enthralled scientists striving to understand its molecular meaning, provided an aesthetic template for artists, and challenged society with all sorts of ethical conundrums. The defining moment for DNA was the discovery of its structure. Published in the science journal Nature 50 years ago this month, James Watson and Francis Crick described how two strands of DNA embrace to form a double helix, and sparked a scientific revolution.
One Gene = One Protein? Not Even Close!
To convince the skeptics that DNA truly was the material of inheritance - the so-called "stuff of life" - it was necessary to show how it could be copied and passed on from one generation to the next. Watson and Crick's model immediately hinted as to how DNA might be copied - each strand of the helix could act as a template to replicate the other.
Another quandary for contemporaries of Watson and Crick was how DNA with its 4-letter alphabet could encrypt the 20 kinds of protein building blocks, called amino acids. The genetic code was cracked in the s, when Marshall Nirenberg, Har Khorana, and Severo Ochoa figured out that three letters of DNA encodes a particular amino acid.
A three-letter word made of four possible letters could have more than enough permutations to encode the 20 amino acids. The sun rose for biotechnology in the s, with some ingenious tricks for manipulating DNA. Boyer, together with Stanley Cohen, then discovered how to clone DNA - by piecing together fragments of DNA from different species and popping them into bacteria, where they could be copied in limitless quantities, like a biological photocopier.
Inin a flash of inspiration while driving on a Californian highway, Kary Mullis figured out how to churn out millions of copies of a DNA segment in a test-tube by a process known as polymerase chain reaction.