Mutation

[gene]

What is a mutation? And How does a cell gets mutated?

[Hades]

there are many mutagens (factors that cause mutations), some happen in different areas, and in different times.

The first kind is point mutation which occurs during the s stage of interphase, is a substitution of one nucleotide for another during the synthesis of dna. Nucleotides are the monomers, if u will of dna. for example, if a wild strand (the blueprint from the initial cell) of dna read:

 

acg agc acg agc

 

a point mutation would occur if it read

 

acg acc acg agc

 

It only takes one substitution to be considered a mutation. Either lethal, detrimental, or nuetral, it all is dependant on so many variables i couldnt begin to tell u. However, dna is coded for in 3's, a-t c-g c-g would represent the code for one amino acid. It is possible that it may still correctly code, and no harm may be done. These mutations occur in the actual dna of a cell and can not be seen in a karyotype.

The next set of mutations occur at the level of the chromosome and can easily be viewed with a karyotype.

Abnormality of chromosome structure happens during the anaphase by bastardly spindle fibers that dont work properly.

Deletion occurs when spindle fibers pull to hard and break off a piece of chromosome... it never reattaches and is just lost.

Duplication and inversion happen when a broken piece of chromosome attaches to a homologous chromosome and when the broken piece performs an acrobatic 180 and reattaches to the same chromosome, respectively.

Finally, translocation occurs when a piece of chromosome attaches to an non homologous chromosome.

Most of these are detrimental. The last accounrs for roughly 5 % of downs syndrome cases.

The last basic kind of mutation is a frame shift mutation. This is an addition of deletion of an entire nucleotide in the code of dna. happens also during the s phase and is detrimental.

acg acg acg

aca cga cg ... note the deletion?

 

Abnormality of chromosome number is the last that ill speak of. I know, finally, its over

 

Aneuploidy is caused by nondisjunction. This sumbitch happens either during meiosis1 when homologous chromosome fail to separate, or during meiosis 2 when chromatids fail to separate.

you conclude meiosis with an odd number of chromosomes.

i.e. , 47 chromosomes instead of 46. If the extra chromosome happened on number 21, it would be called trisomy 21. tri meaning 3, somy meaning of chromosomes. This condition is downs syndrome and accounts for the remaining 95% of cases.

 

thats about everything

[Hades]

also wanted to add that such mutagens are possibly chemical, viral, or due to a radioactive substance.

[YT2095]

substances OR sources, as it`s be hypothethesised that cosmic rays have been responsible for many genetic alterations in Earths life history. and cosmic rays can also blow out silicon substrate layers in micro-chips too!

the A,G,C and T pyramidines and purines stand NO CHANCE! if hit directly by a particularly enengetic particle.

[Skye]

Ok this thread is a little old, but what the hey.

 

YT do you mean UV light from the sun? It mainly affects the links between two pyramidines, i.e. cytosine or thymine. These then bond together and form a dimer.

 

There are a few common chemical processes that lead to mutation.

 

Hydrolytic processes are a common source of depurination, where a purine is removed from the DNA strand, and can lead to nasty deletion. Depurination occurs about 5000 times a day in each of your cells! So obviously it requires an efficient repair system. Hydrolysis can also break the strand of DNA by hydrolysising the phosphate group that joins that bases, and can attack the amino groups of cytosine, guanine and adenine (thymine doesn't have an animo group) by substituting the amino (NH2) group with an oxygen.

 

Oxidative processes attack the double bonds within the base and nuscleosides, and the methyl groups attached to the nuscleosides.

 

Nitrogens within the ring of nucleosides can also be methylated. Cytosine is often methylated in by your body in controlling gene epression though too.

 

Another type of chemical mutagen are ones that incalcate with DNA. They bind to DNA and in doing so push the wrong bases together or the right ones apart. Dyes used to stain DNA, like ethidium bromide, are well known and understood examples.

[Guest Windigo]

heres a good example of a mutation and I would be happy to see if anyone can disprove the aids kids existence in this article. on this site below.

 

http://www.geocities.com/Yosemite/Trails/9723/Drun699.html

[Skye]

No, that's a crappy example because it's so obviously wrong. We have 64 codons (4^3) and none are "turned off".

[Hades]

if im not mistaken, theres 64 codons, but 3 of them 'code' as the stop codon.. perhaps thats what he meant

[Sayonara]

Windigo said in post # :

heres a good example of a mutation and I would be happy to see if anyone can disprove the aids kids existence in this article. on this site below.

 

http://www.geocities.com/Yosemite/Trails/9723/Drun699.html

I will... if you prove the tooth fairy doesn't exist first.

 

Then they tested this kid tosee how strong his immune system was. They took a very lethal dose of AIDS in a petri dish and mixed it with some of his cells and his cells remained completely unaffected.

ROFL, what unmitigated crap.

 

And you know, there is another thing that happened last year - AIDS dropped something like 47% - the largest drop of a single disease in the history of the world

Complete, utter lies. People becoming desensitised to the threat of HIV is one of the reasons infections are rising fast, so if you're going to link to such complete tosh do it somewhere else please.

[YT2095]

"YT do you mean UV light from the sun? It mainly affects the links between two pyramidines, i.e. cytosine or thymine. These then bond together and form a dimer."

 

Skye, Sure UV light is another good example of a radiation that can have an effect. high power RF radiation can also have significant impact on cells, look what happens to the proteins in an egg or peice of meat in a microwave. fortunately our systems often recognise a damaged cell an reject it, but if it`s in the DNA and isn`t TOO corrupt, it can be overlooked, and therein lies the mutation, for good or for bad

[Radical Edward]

Hades said in post # :

if im not mistaken, theres 64 codons, but 3 of them 'code' as the stop codon.. perhaps thats what he meant

 

no, it definitely looks like he meant that most of the codons code for nothing at all - which is completely false.

[Radical Edward]

YT2095 said in post # :

"YT do you mean UV light from the sun? It mainly affects the links between two pyramidines, i.e. cytosine or thymine. These then bond together and form a dimer."

 

Skye, Sure UV light is another good example of a radiation that can have an effect. high power RF radiation can also have significant impact on cells, look what happens to the proteins in an egg or peice of meat in a microwave. fortunately our systems often recognise a damaged cell an reject it, but if it`s in the DNA and isn`t TOO corrupt, it can be overlooked, and therein lies the mutation, for good or for bad

 

microwaves heat things up because they resonate the water, whereas UV is absorbed directly by the DNA.

[Guest Windigo]

Sayonara maybe it hasnt occured to you that not everyone has studied genetics as much as you and you should at least be more modest and not let everyone know how full of yourself you are.

 

Now then.. if anyone has any information of UCLA conducting a study like this please post it.

[Guest Windigo]

here is a link that shows how mutations occur.

 

http://www.genetichealth.com/G101_Changes_in_DNA.shtml#Anchor1

[Sayonara]

Windigo said in post # :

Sayonara maybe it hasnt occured to you that not everyone has studied genetics as much as you and you should at least be more modest and not let everyone know how full of yourself you are.

 

Now then.. if anyone has any information of UCLA conducting a study like this please post it.

The information I was quite rightly scoffing at had nothing to do with genetics.

 

My "tooth fairy" challenge was meant to introduce you to the idea that proving things don't exist is problematic at best.

 

If you wrote the HIV article, it needs work. If you didn't, you have no reason to defend it.

[Guest Windigo]

and no I didnt write or defend the article I was simply offended in the manner in wich I was answered. but no hard feelings because I got an answer.

 

I will see if I can find something factual on this topic of Aids and post it for everyone.

[Sayonara]

OK, just so long as you know I was mocking the article and not you

[[Tycho?]]

"YT do you mean UV light from the sun? It mainly affects the links between two pyramidines' date=' i.e. cytosine or thymine. These then bond together and form a dimer."

 

Skye, Sure UV light is another good example of a radiation that can have an effect. high power RF radiation can also have significant impact on cells, look what happens to the proteins in an egg or peice of meat in a microwave. fortunately our systems often recognise a damaged cell an reject it, but if it`s in the DNA and isn`t TOO corrupt, it can be overlooked, and therein lies the mutation, for good or for bad [/quote']

 

A bit off topic here, but can the microwaves that cook food be harmful in anyway? Some of my friends told me that microwaves were not good for you. I found it hard to beleive that it would be signifigantly more unhealthy than if you were to just put food in a stove or on a BBQ. I looked it up, however all the sites I found that said microwaves were harmful were very obviosuly biased, and had a lot of false information. Plus, all the sites had exactly the same article on it, occasionally just written different. So, I put very little faith in these sites.

 

So, microwaving food, could eating this food cause somebody harm?

[LucidDreamer]

Microwaves are harmful to you if you are exposed to a large, intense amount of them. The amount of microwave exposure from a microwave oven is pretty small if it is operating correctly. Most of the inside of the microwave oven has metal sheeting around it to keep the waves in the oven to cook the food and protect you from radiation. Once the oven is turned off neither the food nor the oven should contain residual microwaves. Microwave food is safe unless you fail to cook meat thoroughly and consume harmful bacteria. You might also want to avoid peering through the plastic window for long periods of time, lol. The amount of harmful radiation from microwave ovens is pretty small; you probably get alot more from your cell phone.

http://www.fda.gov/cdrh/consumer/microwave.html