Fun with Palindromes

taco cat palindrome

Today is 6-16-16… 61616… which, if you hadn’t noticed, is a palindrome -- a word, a number, a phrase, or any other sequence that reads the same backward or forward. If you check out ‘palindrome’ in Wikipedia, there are several examples that pop up, such as “Was it a car or a cat I saw?” or “taco cat.” What is also interesting about palindromes is that they exist in nature as well. In DNA, there is what is referred to as palindrome sequences. Simply put, when a sequence of base pairs on a DNA or RNA strand matches the same sequence of base pairs read backwards on its complimentary strand, they are considered palindromic.  

 

Example of a palindrome sequence:

5'- GAATTC -3'

3'- CTTAAG -5'

 

This biological occurrence has contributed significantly to the origins of what we now call ‘genetic engineering.’ Sequences of the 4 bases that comprise DNA, commonly referenced as A, T, G, and C, that occur naturally as palindromes are sites where a group of enzymes called restriction enzymes can do their work, i.e. cut DNA in a specific, controlled manner.  That ability to ‘cut’ DNA and then either analyze or stitch the pieces back together was the basis for early experiments in ‘gene splicing’ that has grown progressively more sophisticated.

 

But not only are restriction enzymes still used for analyzing or manipulating DNA, but nature has peppered the genome… including the human genome… with palindromic sequences that researchers are still trying to ‘read’ for their meaning.