dna sequencing
National Human Genome Research Institute, Public domain, via Wikimedia Commons.

DNA Sequencing

Genome sequencing is like solving one of the most intricate puzzles in the world, a puzzle made not of cardboard but of DNA. Every living organism, from the tiniest bacterium to human beings, carries a unique instruction manual written in a four-letter code: A, T, G, and C. Sequencing this code helps scientists understand what makes each organism unique, how traits are inherited, and even how certain diseases develop.

In this activity, you will take on the role of a genetic scientist and simulate the sequencing process. Instead of real DNA, you will work with fragments from a paragraph taken from the Harry Potter series. Your task is to arrange these fragments in the correct order to reveal the prophecy hidden within.

Science Involved

Genome sequencing is the process of determining the exact order of nucleotides (A, T, G, and C) in an organism’s DNA. It begins with DNA extraction, where scientists carefully isolate DNA from the cells of the organism. Once obtained, the long DNA strands are cut into smaller fragments, because sequencing machines can only read short stretches at a time.

Each fragment is then sequenced, meaning that the machine identifies the order of nucleotides within that piece. These short sequences, called reads, are like tiny pieces of a vast jigsaw puzzle. However, unlike a picture puzzle, scientists do not have a final image to guide them. They must rely on areas of overlap between reads to determine how the fragments fit together.

Through a process called sequence assembly, computers align overlapping regions to reconstruct the longer DNA strands. This step may involve filling in gaps, checking for errors, and confirming that the reconstructed sequence truly represents the organism’s genome. The final result is a nearly complete copy of the organism’s genetic blueprint, a detailed map of all the instructions that control its growth, appearance, and functioning.

Modern genome sequencing has transformed science. It allows researchers to trace evolutionary relationships, detect genetic disorders, design better medicines, and understand how living things adapt and survive. Each sequenced genome adds a piece to the grand story of life, written in the timeless language of DNA.

dna sequencing Image Credit: National Human Genome Research Institute, Public domain, via Wikimedia Commons

Instructions

Cut out the given fragments from a passage in the Harry Potter series and try to arrange them in what you believe is the correct order.

TO VANQUISH THE DARK LORD APPROACHES…
BORN TO THOSE WHO HAVE THRICE
AND THE DARK LORD WILL MARK
POWER THE DARK LORD KNOWS NOT... AND
FOR NEITHER CAN LIVE
THE ONE WITH THE POWER TO VANQUISH
WILL MARK HIM AS HIS EQUAL, BUT
TO VANQUISH THE DARK LORD WILL BE
AS THE SEVENTH MONTH DIES...
BORN AS THE SEVENTH MONTH DIES... AND
AND EITHER MUST DIE
AT THE HAND OF THE OTHER FOR NEITHER
THE ONE WITH THE POWER
BUT HE WILL HAVE POWER
WHO HAVE THRICE DEFIED HIM, BORN
WILL BE BORN AS THE SEVENTH MONTH
THE DARK LORD WILL MARK HIM AS HIS EQUAL,
THE POWER TO VANQUISH THE DARK LORD
MUST DIE AT THE HAND OF THE OTHER
CAN LIVE WHILE THE OTHER SURVIVES. THE