DNA

[Jo]

Can I ask a really stupid question please?
I do know about DNA, its make up etc but one thing I'm really not sure on is this.
Back in the 80's in the case of Colin Pitchfork when a mass DNA screening happened (he evaded giving DNA but was caught when a college called the police to report the issue someone else did the test), what happens if 2 people (either 2 men or 2 women) end up with the near same DNA results?
I know the chances of having the same DNA sequence as someone else (unles you're identical twins) is like 28 zillion to one of somehting but to come up with a number saying it is possible for it to happen must mean it can and whats to say the person who'd match you isn't your neighbour or comes in for mass screening?

[petey]

Can I ask a really stupid question please?
I do know about DNA, its make up etc but one thing I'm really not sure on is this.
Back in the 80's in the case of Colin Pitchfork when a mass DNA screening happened (he evaded giving DNA but was caught when a college called the police to report the issue someone else did the test), what happens if 2 people (either 2 men or 2 women) end up with the near same DNA results?
I know the chances of having the same DNA sequence as someone else (unles you're identical twins) is like 28 zillion to one of somehting but to come up with a number saying it is possible for it to happen must mean it can and whats to say the person who'd match you isn't your neighbour or comes in for mass screening?

The odds of two individuals having the EXACT same genome sequence is 3 billion to the power 4. This probability is thousands and thousands of times the number of people who have EVER lived, therefore it is deemed to be impossible for DNA to be duplicated.

[nugnug]

theres some dispute over weather it is really 3 billion to one.

it would also depend on how many marker points there using to claim a match

here we used 6 to start with witch was later changed to 10.

in amerca they use 13.

[nugnug]

this site is a good one for understanding dna.

http://www.dnaftb.org/

[Patti]

Can I ask a really stupid question please?
I do know about DNA, its make up etc but one thing I'm really not sure on is this.
Back in the 80's in the case of Colin Pitchfork when a mass DNA screening happened (he evaded giving DNA but was caught when a college called the police to report the issue someone else did the test), what happens if 2 people (either 2 men or 2 women) end up with the near same DNA results?
I know the chances of having the same DNA sequence as someone else (unles you're identical twins) is like 28 zillion to one of somehting but to come up with a number saying it is possible for it to happen must mean it can and whats to say the person who'd match you isn't your neighbour or comes in for mass screening?

Hi Joanne

There will be someone in the world that has the exact DNA that you have.  There is no doubt about that, so don't be kidded.  There will also be hundreds, maybe thousands of people that have the same markers that make up your DNA. 

Lottery numbers are the best way to explain it.

1, 2, 3 , 4 ,5, 6. 


The 6 numbers above will be unique to one or two lottery winners out of millions who take part in the lottery. 

If someone gets 5 numbers out of the 6 for example then that number is still not unique and not a safe match. However, someone with 5 numbers still wins at lottery....Although, it is not a perfect match,  they share some of the winning and, share some of the markers.   

[-Harters-]

Hi Joanne

There will be someone in the world that has the exact DNA that you have.  There is no doubt about that, so don't be kidded.  There will also be hundreds, maybe thousands of people that have the same markers that make up your DNA. 

Lottery numbers are the best way to explain it.

1, 2, 3 , 4 ,5, 6. 


The 6 numbers above will be unique to one or two lottery winners out of millions who take part in the lottery. 

If someone gets 5 numbers out of the 6 for example then that number is still not unique and not a safe match. However, someone with 5 numbers still wins at lottery....Although, it is not a perfect match,  they share some of the winning and, share some of the markers.   

This is simply not true.

[Patti]

This is simply not true.

it is...to be an exact match you have to have all the markers...therefore all the numbers.   

[nugnug]

what is consdired a perfect in some countrys is not considered one here.

and a perfect match here is nothing of the sort in usa.

so its rather complicated.

[petey]

The human genome contains a little over 3 Billion bases, each of which can be one of four options (A, T, G, or C). So the odds of two individuals having the EXACT same genome sequence is 3 billion to the power 4 (which is 8.1 x 10^37) against.
 
This is 8.1 x 10^26 times greater than the number of people who have ever lived.

[Patti]

what is consdired a perfect in some countrys is not considered one here.

and a perfect match here is nothing of the sort in usa.

so its rather complicated.

It is very complicated Nugs, you are right....I don't know anything about DNA. I just have a degree in it...lol 

[nugnug]

oh i dident know you had a degree in it.

[Bridget]

it is...to be an exact match you have to have all the markers...therefore all the numbers.   

That would just indicate a match at the markers, it doesn't mean the other 3 billion thingamajigs match.

[-Harters-]

it is...to be an exact match you have to have all the markers...therefore all the numbers.   

Nope, you are wrong Patti, there are not enough people alive on the planet to make an identical match a likely possibility and the rate of mutation of the genome makes it impossible that a match would occur in the future.

[Patti]

That would just indicate a match at the markers, it doesn't mean the other 3 billion thingamajigs match.

hahahahahahaha I never said that. I said that 6 matches on the lottery was unique and, that it could relate to the one or two winners that have the same numbers for it to be an unique match...

The other winners don;t match at all..but they are likely to share the same DNA in some format, but it is not unique to them only the winner.  And sometimes there are several winners, which means that it is also unique to them....its an explanation that's all.  This was my first lesson in DNA...lol 

[Patti]

Nope, you are wrong Patti, there are not enough people alive on the planet to make an identical match a likely possibility and the rate of mutation of the genome makes it impossible that a match would occur in the future.

ok dear