If a miRNA were 5 nucleotides long, what is the chance of finding a complementar

Question

If a miRNA were 5 nucleotides long, what is the chance of finding a complementary sequence in a randomly selected 5 nucleotide sequence in mRNA? [Assume mRNA sequences to be random and that mRNAs have an equal amount of each nucleotide (A, U, G, and C)]. If an miRNA were 10 nucleotides long, what is the chance of finding a complementary sequence in a randomly selected 10 nucleotide sequence in mRNA? If

you were designing a synthetic miRNA to specifically target a particular mRNA, would you want to design a 5 or 10 nucleotide long miRNA? Why?

Explanation / Answer

1. Length of miRNA = 5 ntd
RNA contains 4 different nucleotides. So, each nucleotide has 1/4th probability to be found at a given position.
The probability of finding a complementary sequence for a 5 ntd long mi RNA = 1/(45)
= 1/1024
The probability of finding a complementary sequence for a 10 ntd long mi RNA = 1/(410)
= 1/1048576

Since the probability for a 10 ntd long miRNA is greater, it is advisable to design a miRNA with greater length.

However, the extent of non-specificity also increases with increase in length.

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.