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Are mutations the driving force in evolution? Is that feasible? Let's do a bit of detective work and see if we can answer these questions.

Considering all the activity in the cell - and we have only looked at a small part of it - it appears that a good number of things could go wrong in the operation. That is an understatement. Geneticists call these errors: saltations, mutations, mutants, sports, or "freaks". Those who write or speak on evolution usually refer to them as mutations. We find two basis types: gene and chromosome mutations.

Gene mutations occur when nucleotide sequences are altered in the DNA helix. One nucleotide base is substituted for another, or perhaps a base is added or deleted. What happens?

Let's say one nucleotide is substituted for another. That's the most common gene accident. If the first adenine (A) molecule of a GAA codon were to mutate into a uracil (U), it becomes a GUA codon. The upshot of this change is that we now have a sequence coding for a valine amino acid instead of a glutamic acid.

This simple, one nucleotide base substitution causes sickle cell anemia. Distorted sickle cells get stuck in tiny blood vessels preventing blood cells from carrying oxygen into the body.

That is so remarkable, it bears repeating. If just one microscopic nucleotide out of three billion goes astray, you could die. That example is not unique. Other nucleotide changes result in consequences varying from negligible to lethal.

Gene mutations are nucleotide accidents. Sometimes a nucleotide is missing or one is repeated or duplicated. That can throw the whole gene out of kilter. A single missing nucleotide can result in a missing protein. If the protein remains, it is likely to be a huge malfunctioning entity. Deformity or death is the most likely prospect for any individual with one or more deleted nucleotide bases. Adding or duplicating a nucleotide in the DNA sequence would reek equal havoc.

A deletion of one or more nucleotides is the gene mutation equivalent of removing the back of your watch and unscrewing one or more of the tiny screws inside of the watch. Would this "screw deletion" likely improve the watch's performance, or harm it? Or would you be surprised if the watch ran at all?

An addition of one or more nucleotides is the gene equivalent of removing the back of your watch and jamming in one or more extra tiny screws. Would that help, hurt, or destroy the watch? And a substitution of one or more nucleotides is the gene mutation equivalent of removing the back of your watch and replacing one or more screws with screws of a different size or even something other than a screw. Once more, it's a pretty sure bet that the change will be detrimental for the watch.

A DNA mutation is nothing more than a mistake, an error jammed into the DNA sequence. Any tampering with what makes a living thing tick is likely to kill or maim it. Occasionally, a gene mutation is neutral. Rarely is it beneficial. Seventeen years of fruit flies prove it. (We will address both beneficial mutations and the fruit fly experiment in future articles.)

In addition to gene mutations, we also find chromosomes mutations. We know that a gene is nothing more than a section of DNA which codes for one or more traits - color of eyes, skin, hair, or length or shape of the nose, ears, etc.

Often a single human characteristic depends upon a combination of several genes. You and I have about 100,000 genes in our bodies. They are organized into 46 chromosomes. Looking at it from the top down, we can say, chromosomes are collections of genes which in turn are collections of DNA sequences.

Chromosomes come in pairs. Normally the male and female each contributes one member to each pair. The number, size, and organization of chromosomes vary among species. At the low end of the totem pole, bacteria have only one chromosome. At the high end of the spectrum, many species have more chromosome than we do. Butterflies have more than 100 pairs, while ferns show more than 600 compared to the 23 pair found in humans.

Changes in the number, size, or organization of chromosomes are called chromosome mutations. Two chromosomes may fuse into one; or one breaks into two; or a chromosome duplicates itself or is deleted. On rare occasions, the whole chromosome rotates 180 degrees at the same location.

Then again, one or more genes will break off one chromosome and join another. Geneticists call this rearrangement "crossing over." A pair of chromosomes exchange a section of one or more genes. Linkage between the genes suddenly and dramatically changes.

Traits which were once closely linked become separated and vice versa. Physical traits are seen in new combinations with greater variety. Sure, variety is the spice of life. But how does this type of mutation fit into evolution? It doesn't. A mishap at the chromosome level does not crank out new traits. It merely reshuffles old ones. We cannot go from bacteria to humans by scrambling chromosomes. It is just another dead end for macroevolution.

Our brief look at mutations really hasn't cleared anything up. Naturalists, you may remember, say that mutations are the driving force behind evolution. Of course, natural selection lops off the rough edges, but mutation is the spark plug - the creative source for engineering new species.

But when we look at the two types of mutations, neither seems promising. Gene mutations produce diseases, monsters, or death, with an occasional neutral result. It is suggested that perhaps on extremely rare occasions, something beneficial might occur. That doesn't seem too encouraging for the bacteria to man scenario.

Even less promising are chromosome mutations which merely mix already existing characteristics. So what makes evolution tick?

We will continue our study of mutations with "Mutations: Facts and Figures": see Evolution:The Devil Is in the Details (Part Four of Six.)

Jerry Boone, Gatlinburg, Tennessee, United States webmaster@merechristianity.us Mr. Boone is a sailor, author, and webmaster of http://merechristianity.us with a Bachelor of Arts degree in Anthropology from Georgia State University [http://merechristianity.us]. His works include: Mere Christianity.us and SAFETY LINE - EVIDENCE OF THINGS NOT SEEN, an apologetic study published 1998.

Model Railroad Layouts: Make a Great Impact With Yours

Model railroad collectors consider the act of designing and constructing track plans to be a fine art. This is because you need to exercise a number of elements of art and design when looking to set up your model railroad layout. This includes sculpting, modeling, building and painting as well as electronic engineering to some degree.

One of the most common mistakes made by individuals especially beginners is that they purchase a model train set without taking the availability of space into consideration. However this is one of the most important facts that you need to keep in mind when looking to lay out your tracks. Check out a good model railroad magazine for some good examples.

If you are fond of changing your tracks around frequently than you would want to make use of an integrated roadway track to facilitate your movements. The ideal surface to work upon is a tabletop that measures 4' x 8'.

It is highly recommended that you play around with some temporary layouts even if you intend on setting up a permanent one. This will give you a better feel and understanding of space planning. One thing that you need to keep in mind from the start is that the strength of the surface that you will use to layout the tracks needs to be strong enough to support the scale of your model train.

Modular layouts tend to be quite popular amongst train collecting enthusiasts. You will be able to find modules in varying lengths although the standard is about 2 feet. The standards have been published for the purpose of making it possible to position and wire modules that have been constructed by different makers.

If you're looking to build a permanent layout then you need to make the right choice when it comes to the scale of your model toy train. This will have a profound impact on the satisfaction level of your model railroad track plan.

In general O scale is extremely large and takes up a lot of space which is why they're usually set of tools. You would want to stick with HO and N scale model trains as they can be set up in a relatively smaller place. In case you have a very limited availability of space you can go for the downsized Z standard.

Contemporary model train collectors are fond of constructing narrower layouts that go along the walls of the particular room in which they are placed. L and U shape layouts and track plans are also very ocular today. You might also want to add an island so that you can create an M shaped track plan for your model train.

One of the most interesting model railroad track plans is the multilevel layout. This is a variation on the around the walls style which is achieved by putting a shelf measuring about 2 feet above and other table that measures about three or 4 feet. You can use a helix or a vertical spiral track in order to construct a multilevel layout where your train will actually be moving through the two-levels.

The above-mentioned layouts are just some examples model railroad track planning that you can experiment with as you design your masterpiece. It is generally advised to start off with simpler plans and then slowly progress to the more complicated track plans for your model railroad.

About the Author

Michael Weston is a Model Train Expert. For great information on
model railroad track
, visit
http://www.modeltrainsexpert.com

Rook, Conch, and Anti-Helix Piercings: What's the Pain and Price?

I'm thinking about getting a new piercing and I'm trying to make up my mind about which one to get. I've wanted to get the Rook for a while but I've heard such differing opinions on the pain that I've gotten a little confused.

I have a very low pain threshold when it comes to piercings and a high threshold with tattoos. For some reason piercings just hurt a lot worse for me. I have 8 piercings and they all hurt to some degree though a few much worse than others. So far for me, the most painful was my bellybutton and both lobe piercings. My cartilage on both ears and tragus in one ear didn't hurt at all.

So my question is this: On a scale of 1 to 10 how much does each the Rook, Conch, and Anti-Helix piercing hurt? What is the general cost of each?

Thanks

Any of those will cost around $35. The forward (or anti) helix is virtually painless. The Conch is the hardest, thickest cartilage in your ear, and will be fairly painful if done with a needle. I would recommend that you request the piercing artist do that with a dermal punch. If they do not have punches, ask if they can order one.

Rooks actually go through two layers of cartilage almost as thick as the conch. It will be pretty unpleasant, but nothing you can't handle. Healing a cartilage piercing is much more painful than actually getting it pierced.

Sherwood School District names Redmond administrator new superintendent
Heather Cordie, assistant superintendent in the Redmond School District, will replace Dan Jamison who will step down June 30.

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