Just a thought, why is it that we can't change our somatic DNA? I find it strange sometimes that after a few billion years of eukaryotic multi-cellular evolution we haven't been able to modify our somatic genes. does anyone know of organisms that can actually change its somatic DNA half-way through its development aside from mutations?

Simply put, why bother? It's easier and less complicated to just keep the genes around, and express different ones at different times and places.

 

Besides, any molecular mechanism to alter DNA will not be able to assure or predict in any way whether the alteration is beneficial or not. Given that it seems most alterations of DNA are harmful (mutations), there's really no plausible difference from somatic mutations nor any benefit over them.

 

Mokele

well, one reason is that more genes = more energy required for mitosis.

 

but if the alterations exist, natural selection would select on the beneficial alterations just as it selects inherited genetic traits

Here's a site that shows some examples.

 

http://www.abdn.ac.uk/~gen155/lectures/dna-rearrange.html