# VERY HARD Genetics puzzle A LEVEL BIOLOGYWatch

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#1
Hmm, this one is a real puzzler:

A DNA was found to have a double helix of nucleotides, containing 6 different nucleic bases:

J, L, M, K, I, H

Of these, J, L, M were found to be pyrimidine.

Studies showing the following ratios:

H/ J 1:1
H+I/ J+M 1.02: 1
H+K/ J+M 1.14: 1
H+K/ J+L 1.01: 1

Assumign that the base pairing rules are similar to the Human DNA, what can we conclude from the data?
********************************

Well we can assume that J, L, M can be linked to K, I, H in some order. From the ratios we see that H:J is the perfect link. But I'm stuck for the rest....
0
15 years ago
#2
Come on somebody, help Phil out here!
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15 years ago
#3
Well, I am fairly sure that the base pairing is as follows:

J with H
L with I
M with K.

It is also possibly to deduce the relative abundance of the nucleotides from the ratios.
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#4
(Original post by Ralfskini)
Well, I am fairly sure that the base pairing is as follows:

J with H
L with I
M with K.

It is also possibly to deduce the relative abundance of the nucleotides from the ratios.
Can you explain how you got the deduction please.
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15 years ago
#5
(Original post by 2776)
Hmm, this one is a real puzzler:

A DNA was found to have a double helix of nucleotides, containing 6 different nucleic bases:

J, L, M, K, I, H

Of these, J, L, M were found to be pyrimidine.

Studies showing the following ratios:

H/ J 1:1
H+I/ J+M 1.02: 1
H+K/ J+M 1.14: 1
H+K/ J+L 1.01: 1

Assumign that the base pairing rules are similar to the Human DNA, what can we conclude from the data?
********************************

Ratio of H/J is 1:1, and we know that H and J is a pair consisting of a purine and a pyrimidine therefore they are likely to bond together.

That means that either L bonds to I or to K, (because we are told that L is a pyrimidine and so I and K are the two remaining purines), but if it bonded with L then the ratio H+K/J+L would be 1:1, which it isnt.

That is what I think anyway. I could be wrong, if the relative abundance of more than two nucleotides are equal but thats the best I can come up with.

Well we can assume that J, L, M can be linked to K, I, H in some order. From the ratios we see that H:J is the perfect link. But I'm stuck for the rest....
0
#6

Therefore you conclude that K bonds to M. But the HK: JM ratio is 1.14:1
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