ELI5: Explain Like I'm 5

Fluorescence in situ hybridization

Okay, so you know how we have these teeny tiny things called cells in our bodies, right? Like the little Lego bricks that make up a big Lego creation!

Well, sometimes scientists want to take a closer look at those cells to learn more about how they work. And that's where fluorescence in situ hybridization (FISH for short) comes in!

Imagine that each cell is a little city and inside that city, there are these important "workers" called genes. Genes are like the instruction manuals that tell our cells what to do and how to grow.

Scientists use FISH to look at those genes and see if they're working the way they're supposed to. To do this, they take small pieces of DNA (kind of like the letters that make up a word in a book) that match specific genes they want to study. Then they attach a special chemical dye to those pieces of DNA that make them light up under a microscope.

They then take those pieces of glowing DNA and put them into the cell they want to study. If that cell has the gene they're looking for, the DNA pieces will "stick" to the matching gene and light up!

So, now the scientists can see the glowing genes on a microscope and count how many there are or see where they're located in the cell. It's like finding where all the light-up stars are in a dark night sky!

Overall, FISH is a cool tool that helps scientists learn more about our cells and how our bodies work.