Dna

Please dummy down this one for me, I don't even know how to read it properly:

Your DNA code is composed of a series of four nucleotides: adenine, guanine, thymidine and cytosine (A, G, T and C, respectively).

1) What is the probability an individual has the following nucleotide sequence: “TATATA” at any particular position? (assuming independence).

2) What is the probability that an individual has k T’s in their DNA code at any particular position? (k can be any integer and you may assume independence). Here we're looking for the probability of k consecutive T's.

This is puzzling. If, as you appear to be saying, you have never taken a probability class, where did you get this problem? If "A", "G", "T", and "C"are independent (and "equally likely" which you don't say) then the probability of any one of them appearing at a particular position is 1/4. In particular the probability of getting "TATATA" is (1/4)(1/4)(1/4)(1/4)(1/4)(1/4)= 1/4096= 0.000244140625 and the probability of k consecutive "T"s (in fact any k specific neucleotides) is \(\displaystyle (1/4)^k\).

HallsofIvy said:

This is puzzling. If, as you appear to be saying, you have never taken a probability class, where did you get this problem? If "A", "G", "T", and "C"are independent (and "equally likely" which you don't say) then the probability of any one of them appearing at a particular position is 1/4. In particular the probability of getting "TATATA" is (1/4)(1/4)(1/4)(1/4)(1/4)(1/4)= 1/4096= 0.000244140625 and the probability of k consecutive "T"s (in fact any k specific neucleotides) is \(\displaystyle (1/4)^k\).

Click to expand...

Thank you. I never said I never took a probability class but rather this question doesn't make much sense to me. Sometimes these questions "assume" a person has a background in baseball or a background in medicine...etc, that's why this question didn't really click. I will continue to ponder on for a little bit, hopefully I'll see the light. Thanks again.