A few questions about genetics/evolution!?

Question

Okay, these are a few things that I have wondered about for a long time, but I just got the idea to ask them now. :)

1) What the hell is a gene? Is it just a designated portion of nucleotides? I know that it is a part of a chromosome, but is this how it works: DNA is a double-stranded collection of nucleotides. This DNA "bunches" into bundles that are called genes. These genes collectively form 1 of 23 chromosomes. ?????

2) What the hell is up with evolution? Yeah, I get it that things evolve, but for example, I remember reading about a fish that had 2 eyes but because it always laid on its side, the fish eventually evolved so that both eyes were on the same side of the head. How on earth does that happen? Just because something is more convenient for your lifestyle, how can that affect your genetic makeup?

3) Lastly, I've always been taught that DNA --> RNA --> Protein... So how does your DNA determine what you look like? I don't see facial features in there anywhere!

Thank you soooooooooo much! I will pick a best answer TODAY!!!!!!!

Answer 1

1) A gene is a subsection of DNA. The DNA does not "bunch" into DNA, but rather, a strand of DNA (as in a chromosome) consists of hundreds-of-thousands to millions of nucleotides ... and buried in that long sequence, are shorter sequences called genes. Only about 2% of that DNA are actually genes (i.e. code for proteins). The remaining 98% of that DNA is just "junk" ... leftovers from 4 billion years of copying, copying, copying, ... in other words 4 billion years of evolution.

The way I like to explain it is that your DNA is like a huge encyclopedia containing all the recipes for proteins that your cells can manufacture, and all the instructions for when, where, and how much of those proteins to make. It is divided up into 46 volumes (chromosomes) ... although this is more like two 23-volume encyclopedias that have the same items, but sometimes slightly different text in each entry. The genes are like the entries in the encyclopedia ... some very short (half a page), others quite long (many pages) ... but these essential entries are buried in page after page of complete gibberish (junk DNA).

2. "Just because something is more convenient for your lifestyle, how can that affect your genetic makeup?" It can't. That is the the Lamarckian theory of evolution (that an individuals lifestyle can somehow affect its genes, and thus get passed on to offspring), and there is no mechanism for that transfer of information about the environment to your genes. Instead, this is where Darwin's theory of natural selection comes in. It is *statistical* ... evolution happens to a *population* ... whatever the lifestyle of the entire group is, those individuals best suited for that lifestyle will tend, *ON AVERAGE* to produce more offspring. And this is how information about the environment gets into the genetic makeup *OF THE GROUP* (the species).

The fish you are talking about are flatfish, like flounders and halibut. They are born like normal fish, and swim upright. But their lifestyle as adults is to lay on their sides on the sandy bottom, and their opposing eye actually migrates out if its eye socket to the "up" side of the fish.
Here is an explanation by the famous Richard Dawkins on the evolution of the flatfish (the halibut).
http://www.youtube.com/watch?v=bldN-lbyqsE

It is an *excellent* piece of evidence for evolution rather than "design", because it is *clearly* a modification of a fish that once swam upright ... and a *lousy* design for a fish that lies at the bottom of the sea (better designs are clear in examples like skates and rays).

3. Yes you are correct. Genes eventually codes for proteins (although in a very complex way ... where some genes code for when other genes are turned on or off, or how much of a particular protein to use in a structure, rather than the composition of the protein itself). Your facial features are determined by the bone structure of your skull, musculature and skin, all constructed from proteins. Your skin color, eye color, and hair color are determined by the amount of protein called melanin.

Answer 2

IN SUMMARY

The others have done a decent job of explaining what DNA is. But for the two questions, several text books are required.

Here is a summary.

There has always been questions about one distinct species evolving into another. Some believe that despite the missing smooth gradations between species that one species can by many random mutations and the natural deselection of unsuitable mutations can change into another species over time.

While others believe that the very fundamental building blocks of life must be sufficiently complex to disallow their random assembly.

The implications of either believe system is not as dire as there is no God or there is a God. Rather, now that the very most fundamental mechanisms of molecular replication in extreme fidelity are much better understood it will soon be possible to clear this disagreement up.

Should self replication be found to be impossible, then the mystery of the origin of life is simply moved back to the back burner again to sit beside the origin of the matter-energy space-time of the universe. We still don't know where that came from either.

Many on both sides of this issue feel strongly that others must also beleive the they way they do. But the fact is that a belief in neither opinion will greatly hinder or help research.

Now to your third question.

If we understood the answer to this question, we could genetically engineer any structure that we wanted. We could plant a seed for a house and have it grown to our specifications. I am afraid as yet all we know is how the instructions for building proteins are stored in DNA and how these instructions are translated into those proteins.

We are rapidly learning more about how the proteins actually carry on the processes of life.

Jerry

Answer 3

1)/3) I can answer 1 and 3 together. A gene is a sequence of DNA that codes for one (or in some cases a few) proteins. Proteins include enzymes as well as structural proteins, transport proteins, and all sorts of things. They do all the work in your body and form your face.

2) I always use the example of artificial selection. I'll use cabbage. People bred wild cabbage for successively larger and larger florets; until they got broccoli. Others bred wild cabbage for larger and larger leaves and got kale. Now replace people with "environmental pressures" and you get similar results. Variation exists within any population, and by selecting from what already exists (and also the addition of an occasional mutation), you can have very different products.

Answer 4

1) A gene is a section of DNA that does something. So you have a gene for your hair color. It is one gene because it does something.

2) What happens is random mutations always occur. Most of the time the mutation makes it impossible for the animal to live, so it dies. But sometimes the mutation gives it an advantage over others, causing it to survive disproportionately. So what happened is one fish was born with both eyes on one side, but it could see better so more of those lived.

3) The proteins are what make you up. Before you are born, your facial features form exactly the way the DNA tells them to. This happens with chemical signals made by proteins to tell how to make a hand, heart, or face.

Answer 5

Point 2 - you hit the nail on the head - how does that happen!

Simple answer - it doesn't.

Natural Selection happens - this is observable.

Evolution, in the sense of microbe-to-man is a hypothesis. It has never been observed, and is highly controversial. Proponents claim that Natural Selection plus time gives evolution, but have not demonstarted it.
The proposed mechanism is genetic mutations. To evolve from microbe to man (or fish to reptile) requires the addition of a vast amount of genetic information. The problem is, all observed mutations are either information neutral or lossy.
Mutations simply do not increase information as evolutionists would have us believe. (Unless they are hiding their evidence :) )

The fish with two eyes on one side of its head was designed like that, since it lives on the ocean floor looking up!

The suggestion that one fish just happened to be born with two eyes on one side is just preposterous. Did its parents just happen to live in the silt and sand with one eye in the sand!?
Did it just happen to miraculously evolve a new lifestyle along with its newly place eye?
Come on - think it through and don't peddle fairy tales :)

Answer 6

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