DNA (deoxyribonucleic acid) is your body’s instructions written in a special alphabet. This alphabet has only four letters in it – A, T, G, and C. A is short for adenine; T is short for thymine; C is short for cytosine; G is short for guanine.
The letters we read in books or on a computer screen are flat. But the DNA alphabet is not flat. It’s more like a beautiful, spiral ladder, called a double helix. The letters are the rungs of the ladder and the sides of the ladder are made of special atoms and sugars.
The four letters of the DNA alphabet are like pieces of a puzzle. A and T fit together and G and C fit together. In our alphabet, we can make all kinds of words that are lots of different sizes. In the DNA alphabet, all words are only three letters long. These words are called codons. A word might look like ATG or GCA. If you put these words together, you can make a DNA sentence called a gene. Genes tell each cell in your body what to do.
Half of your genes come from your mom, and the other half come from your dad. Scientists can look at DNA to understand how traits like hair, skin and eye color are passed on from parents to kids. They can also study DNA to learn how diseases are passed on and how diseases work.
Emmanuelle Charpentier and Jennifer Doudna are scientists who invented a powerful way to change DNA, called CRISPR.
CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats, and it gets its nickname by putting together the first letter of each of the words in its name.
CRISPR works like a pair of scissors that lets scientists change the DNA in plants and animals by cutting out the exact parts that scientists pick. It also allows them to put together new pieces of DNA. In 2012, Doudna and Charpentier discovered it by figuring out how bacteria protect themselves from viruses. Their experiments showed that bacteria use an enzyme called Cas9 to chop up and get rid of viruses.
The really special thing about CRISPR is that it can quickly and easily change any gene in any plant or animal. This is something that was impossible before. Scientists have already used it to fix some diseases in animals, to fight viruses, and to stop mosquitoes from biting.
As exciting as this discovery is, scientists have been slowly and carefully learning the best ways to use it. They also have to think very carefully about how the changes that they make in human DNA will be passed down to future generations.
Charpentier and Doudna have won many awards for their discovery of CRISPR-Cas9. In 2020, they won the Nobel Prize in chemistry. A Nobel Prize is one of a set of prizes that are awarded every year to people who have done important work in science, literature, economics, or for world peace.
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