In a palindrome repeat, the nucleotide sequence is the same in both directions. Each repetition is followed by a short portion of the spacer DNA from previous exposure by a foreign DNA (ie a virus or plasmid). The small group of cas genes (CRISPR-associated system) is located next to the CRISPR sequence.
Further Explanation
The CRISPR / Cas system is a proxy immune system that provides resistance to foreign genetic elements such as those present in plasmids and bacteriophages which provide a form of the adaptive immune system. RNA stores a spacer sequence that helps the Cas protein recognize and cut out exogenous DNA. Other RNA-guided Cas proteins cut off foreign RNA. CRISPR is found in about 40% of the genomes of bacteria that have been sequenced and 90% of the archaea that have been sequenced.
A simple version of CRISPR / Cas called CRISPR / Cas9 has been used to modify the genome. Cell genomes can be cut to the desired place so that existing genes can be removed and newly added. This technique can be used for a variety of things, from medicine to improve seed quality.
CRISPR / Cas9 has become a very popular gene-editing tool today. This happens because of the simplicity, high efficiency, and usability of this system. Of the many technologies and systems for gene editing techniques, CRISPR / Cas9 is considered the most user-friendly technique. Although its use still reaps a lot of debate at the ethics committee and is considered a double-edged knife, its use for molecular biology research is clearly only limited by imagination.
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CRISPR / Cas9
DNA
Details
Class: High School
Subject: Biology
Keywords: CRISPR, DNA, Cas9
