Are genetic mutations through radiation different than them from mitosis or meosis

[cameron marical]

I was curious as to whether or not mutations differ by what they are caused by. Do they? I notice that most mutations {I think} acquired through things like UVA or UVB or certain chemicals just cause cancer {wich is from what I understand, a mutation}. Why is this?

 

Why is cancer so frequent, instead of mutations that do something like change your skin color or the like?

 

Can you, or a plant, or a virus, get a mutation from external sources in the same way as you get them from internal? Mutations are just changes in the DNA right?They are just copying errors or externally promoted, {so I have read}, so I am guessing that their is no difference.

 

Can an externally caused {say UVA} mutation be passed down to future generations?

 

Can viruses mutate in ways other than their own "copying errors"? Like by sunlight, etc...?

 

thanks guys, I know this is alot.

[GDG]

I was curious as to whether or not mutations differ by what they are caused by. Do they? I notice that most mutations {I think} acquired through things like UVA or UVB or certain chemicals just cause cancer {wich is from what I understand, a mutation}. Why is this?

 

UV radiation tends to cause DNA damage by making pyrimidine dimers (T and/or C). In contrast, chemical mutagens typically either attach to DNA covalently, chemically modify a base, or insert between the stacked bases (called intercalation).

 

Why is cancer so frequent, instead of mutations that do something like change your skin color or the like?

 

Most of the time, DNA damage in your somatic (non-sperm or egg) cells causes the cell to undergo apoptosis. During replication, the cell hits a snag (say, dimerized T bases, that prevent replication from proceeding): when replication times out, the cell self-destructs. Only if the cell has a few mutations that disable the apoptotic system can it continue to divide. Enough accumulated mutations, and you have a beginning tumor.

 

You wouldn't notice a single white (or black) skin cell. You do notice several thousand in a melanoma...

 

Can you, or a plant, or a virus, get a mutation from external sources in the same way as you get them from internal? Mutations are just changes in the DNA right?They are just copying errors or externally promoted, {so I have read}, so I am guessing that their is no difference.

 

Yep, but we call it "gene therapy" when applied to humans

 

Can an externally caused {say UVA} mutation be passed down to future generations?

 

Only if it is present in your germ cells (ending up in sperm or egg).

 

Can viruses mutate in ways other than their own "copying errors"? Like by sunlight, etc...?

 

thanks guys, I know this is a lot.

 

Virus DNA (and RNA) is subject to all the same mutagens as our DNA, and typically lacks the proofreading (in whole or in part) that we have in our polymerases. In addition, some viruses (like flu) can reassort -- basically mix and match similar genes.

[cameron marical]

Yep, but we call it "gene therapy" when applied to humans

 

So there is no difference whatsover between mutations from UV rays vs. errors in mitosis that escapes apoptosis?

 

Just want to make sure.

 

 

Virus DNA (and RNA) is subject to all the same mutagens as our DNA, and typically lacks the proofreading (in whole or in part) that we have in our polymerases. In addition, some viruses (like flu) can reassort -- basically mix and match similar genes.

 

Just how often do viruses mutate? I know that it varies in different viruses, like HIV mutates really often, when the cold mutates no as much, but, just how often does say the flu virus mutate? How long does it take for it to adapt to its environment, {on average}, in say an environment, like a chicken egg vs. it being used to living in a human?

 

Thanks for the info.

[Daniel Torres]

On 24/6/2009 at 9:53 PM, cameron marical said:

Why is cancer so frequent, instead of mutations that do something like change your skin color or the like?

the UV rays in addition to causing damage to DNA, are responsible for the production of point mutations in relevant genes such as p53, consisting of transitions occurring in dipyrimidine sites. The accumulation of mutations in the suppressor gene of p53 tumors induced by UV radiation was found at the beginning of the skin tumor process.
you can find enough information in this article: " Morales, C., & López-Nevot, M. A. (2006). Efectos de la radiación ultravioleta (UV) en la inducción de mutaciones de p53 en tumores de piel. Oncología (Barcelona), 29(7), 25-32."