Say you have an organism with a genome of 1 thousand bases 1

Say you have an organism with a genome of 1 thousand bases (10³) and a forward primer made up of 4 nucleotides (aka, a 4-mer).

Please write out your work, but no need to do the arithmetic until part (f).

B.Pick a random 4-nucleotide position in the genome: what’s the probability that your forward primer matches there? Focus for now just on one strand of DNA.

Solution

Assuming the genome to be random the probability of a random 4 mer primer to bind a random nucleotide position in one strand is 4 to the power 4 as 4mer primer and every place has probability od choosing one out of four nucleotide i.e. A, T, G, and C.