Is evolution an expression of changes occurring in the DNA molecules of cells?

Question

My reasoning is that physical changes would be caused by changes in the genes and changes in genes would be retained and passed down the generations.

Answer 1

Sort of. Evolution is based on a random mutation, or change in the DNA base sequence resulting in a new trait. If this trait is favoured positively then it will give the organism an advantage and so more of that organism and it's descendants will survive to pass on the favourable gene.

Think of it as the ancestors of giraffes. Somewhere along the way a mutation gave one of the giraffes a longer neck and so it was able to reach higher leaves on trees that the other animals couldn't reach. This benefitted the animal and it survived better to pass it's genes on to the next generation and so on. You should know that the majority of mutations have negative effects as in hereditary diseases.

Answer 2

If you look at unicellular organisms, that is close to the definition of evolution. However, evolution is defined as change in allele frequency in a population between generations. A single cell that acquires mutations has the ability to pass on those changes when it divides (unless the mutation is not beneficial and reduces fitness) and thereby changing the representation of that version of DNA in a population.

It's more complicated in multicellular organisms. Mutations have to be in the germline (sperm or oocyte) otherwise the changes do not get passed into the next generation and the variant dies with the individual.

Answer 3

that is the mechanism of evolution. just to add, changes don't need to only occur in genes... there are also elements that control the expression of genes (regulatory elements).

consider that between humans and chimps, our DNA is 95-98% identical. many of the genes have the same sequences. part of what makes us different is that changes in how the same genes are expressed occurred. for example, it's believed that in humans, the genes that control brain developed are regulated differently than in chimps, even though the genes themselves are pretty much the same.

Answer 4

this is an area of microbiology and very complex. But of course the sort of changes that lead to evolution have to be changes in the gene code some very slight indeed. I have not yet read the selfish gene I am working on The blind Watchmaker

Answer 5

While that's a correct statement, it's missing the environmental testing of the phenotypic characteristics resulting from expression of the allele set.

Deleterious alleles may not be retained over a long period of time. Your statement doesn't say why. Evolution may be based in biochemistry, but it's a property of populations, not zygote nuclei.

Answer 6

What a ludicrous post. DNA is shown medical concept. Your post is insulting as you're patently implying that Christians very own neither intelligence nor situation-loose experience.

Answer 7

I recommend reading 'The Selfish Gene' by Richard Dawkins
http://www.scribd.com/doc/3812/The-Selfish-Gene-Richard-Dawkins

Answer 8

Environmental stress is what drives evolution.
Also this is NOT an area of Microbiology, it is Molecular Genetics.

Answer 9

That is essentially correct.