There is much symmetry in animals. Does this imply certain DNA strands are read twice to create such symmetry?

I ask because I'm curious about evolution. Since we are the essentially the result of millions of mistakes in the construction of DNA, why are we symmetrical? The blueprint for my left arm is exactly backwards that of my right arm. I would think this means our certain strands of our DNA is read at least twice when we are developing.

If certain strands are not read twice, then due to probably the chances of humans being symmetrical is virtually zero and I would think this disproves the Theory of Evolution.

3 Answers

  • 1 decade ago
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    Let's take a programmers viewpoint.

    You would have to code the algorithm for the development of an "arm" only once, you only have to include something that will say right or left. DNA is not read twice for extremities... :)

    There is no direct code for an extremity - an arm will grow and develop as a consequence of a multitude of genes switching on and off. It is like a chain reaction. It is the integrated function of thousands of cells that will lead to an arm.

  • 1 decade ago

    We have two copies of each chromosome, correct? At development one of them becomes 'turned off' and the other one is used to create the cells needed and so forth. I do not believe that the DNA is being read over twice so you can have two arms, two legs, two kidneys and so forth. Anatomically we are not symmetrical if you take a second look at that statement - the right and left lungs are different with the left having only two lobes and being smaller (to accommodate the heart) while the right one has three lobes.

    Finally, I believe the only symmetry we have is the formation of the blastula, where we start with a single cell that divides into two, then four and so forth. ;) Maybe THAT'S where out symmetry comes from.

  • 1 decade ago

    i dont think your right arm and left arm are built exactly the fact one of mine is just cause your symmetrical doesnt mean that its the same DNA

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