The RNAs acting in RNAi are about 20 nucleotides long. To judge whether it is possible to uniquely target a particular gene with an RNA of this size, consider the following calculation: what is the expected frequency of occurrence of a specific 20 nucleotide sequence? The probability of finding this sequence is . Therefore, the frequency of occurrence of this sequence is one in nucleotides.
Added by Mar-A C.
Close
Step 1
The probability of finding a specific nucleotide at a particular position in a 20 nucleotide sequence is 1/4 (since there are 4 possible nucleotides: A, U, G, C). Therefore, the probability of finding the specific 20 nucleotide sequence is (1/4)^20. ** Show more…
Show all steps
Your feedback will help us improve your experience
Shaiju T and 61 other Biology educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
Suppose a target sequence for CRISPR-Cas9 editing is 20 bases long and the haploid genome size is 2.5 billion nucleotides. About how many times would this sequence be expected to appear in the genome at random assuming that all four bases are equally frequent? About once About 10 times Extremely rarely About 10,000 times About 100 times
Nicholas M.
Given that there are four characters (Adenine, Guanine, Cytosine,Thymine) in 25 character strand of DNA, what is the chance that a poly-atail of twenty five adenines can occur in sequence if they occur randomly in nature?
Steven C.
The total number of possible amino acid sequences in a polypeptide chain is staggering. Given that there are 20 amino acids, potentially there could be $20^{100}$ different amino acid sequences just for polypeptides only 100 amino acids in length. However, the actual number of different polypeptides occurring in organisms is only a tiny fraction of this potential. What insight does this finding provide into the evolutionary process?
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
Watch the video solution with this free unlock.
EMAIL
PASSWORD