I think I'm missing a key concept here.

 

Do DNA mutations have to occur in gamete cells in order to be passed on to offspring? For example, if a cosmic ray tweaks the DNA in a cell on the end of my elbow - how could it possibly be passed on to future generations?

 

When scientists speak of DNA mutuations that are inherited, they must be talking about mutations that occur in very specific cells, yes?

 

I'm confused.

True, the mutations must be present in the gamete cells. The process of meiosis involves the production of gamete cells. During meiosis there is one replication event, two chromosome division events, and an event where sister chromosomes exchange DNA, called crossing over. During any of these events, or during another event mutations can occur that will be present in the fertilized egg and all the resulting cells of the organism.

Thank you!

 

I also found this in Wikipedia (hilites are mine):

 

Mutations are permanent, sometimes transmissible

(if the change is to a germ cell)

changes to the genetic material (usually DNA or RNA) of a cell. Mutations can be caused by copying errors in the genetic material during cell division and by exposure to radiation, chemicals, or viruses, or can occur deliberately under cellular control during the processes such as meiosis or hypermutation.

 

So the germ cells are also called gametocytes and, via meiosis, create gametes. I can see how mutations in those cells could be heritable. I'm also curious about the impact of DNA mutations in other cells. Even if they are not heritable, can they change the phenotype of the individual?

 

This is cool stuff.

I'm also curious about the impact of DNA mutations in other cells. Even if they are not heritable' date=' can they change the phenotype of the individual?

[/quote']

The body can deal with a mutation in a single cell fairly well; it usually just kills it if it affects the cells function greatly. If it is a small thing, such as the mutation in a protein that is not essential to the cells function, then that cells lack of production of the protein is unlikely to affect the body too much because there are probably multiple cells in the body that will still be producing the protein. However, sometimes a mutation in one cell can still greatly affect a person; an example is cancer.

 

Edit: Though in cancer there is heredity because the cancer cell divides.

I've also heard that there may be a link between stem cells in the body and cancer, what do you think of the theory that cancer is the result of a stem cell that has mutated due to outside forces?