Friday, April 9, 2010

Centromeres and telomeres and bricks?

Today we're taking a little masonry detour.  The system I've been describing the past few entries is some interesting geometry, I think it's fundamental and basic, and may well exist in nature.  In particular, I propose that it may exist in features of DNA.

Most of you probably know that DNA is a double helix.  Think of a DNA as a big "X".  The ends of the 'x'  are telomeres, the center of the 'x' is the centromere.

 Centromeres are an originating site of DNA replication (copying begins here). Telomeres are a terminating site of DNA replication. It is proposed that the structures of telomeres and centromeres approximate a structure wherein a combination of four right circular cylinder sections (whose 2 axes of rotation are at right angles to each other) of radius = 1; and also of a section of a hemisphere of radius = 1.5. Here the double helix of DNA is viewed as a right circular cylinder of radius = 1.5. Cylinder sections combine (superimpose) with a spherical section through a four-fold axis of rotation. The geometry of this arrangement may create two optimal energy states simultaneously. This arrangement may be seen as a natural attempt to “square the circle.”


A telomere is a region of repetitive DNA at the end of chromosomes, which protects the end of the chromosome from destruction. Derived from the Greek telos (end) and meres (part).

During cell division, the enzymes that duplicate the chromosome and its DNA can't continue their duplication all the way to the end of the chromosome. If cells divided without telomeres, they would lose the end of their chromosomes, and the necessary information it contains. (In 1972, James Watson named this phenomenon the "end replication problem.") The telomere is a disposable buffer, which is consumed during cell division and is replenished by an enzyme, the telomerase reverse transcriptase.

This mechanism usually limits cells to a fixed number of divisions, and animal studies suggest that this is responsible for aging on the cellular level and affects lifespan. Telomeres protect a cell's chromosomes from fusing with each other or rearranging. These chromosome abnormalities can lead to cancer, so cells are normally destroyed when telomeres are consumed. Most cancer is the result of cells bypassing this destruction. Biologists speculate that this mechanism is a tradeoff between aging and cancer.

I propose that the following geometry may be present in a telomere:

The centromere is a region, often found in the middle of the chromosome, involved in cell division and the control of gene expression.  I propose that this geometry may be present in a centromere:\

Why bother with this? Centromeres are largely responsible for cell reproduction, when centromeres malfunction genetic disease results; telomeres are largely responsible for aging. Any insight into the functionality of these structures is important to science and medicine.

Here's an interesting article on how geometry can have a direct effect on gene expression.  I owe this reference to Alan Michelson, who brought it to my attention, as if to say:  "maybe you're not so crazy Pete."  Thanks Alan.  Here's the article.

This is just the beginning of this discussion, we'll pick it up nex time.  This is a tricky subject.

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