Single-cell sequencing facts for kids

Single-cell sequencing is a special way to study the DNA or RNA from just one single cell at a time. Think of it like reading the unique instruction manual for each tiny building block of life. This method uses advanced sequencing technologies to get a very clear picture of how individual cells are different. It helps scientists understand what each cell does in its own tiny environment.

For example, in diseases like cancer, looking at the DNA of single cells can show small changes, called mutations, that are only in a few cells. When a body grows and develops, sequencing the RNA from single cells can help us understand how different types of cells appear and what they do. Even tiny germs that seem identical can have small differences. Single-cell sequencing can find these differences, which might help these germs survive in changing places.

What is Single-Cell Sequencing?

A typical human cell has billions of DNA building blocks and millions of RNA messages. Usually, when scientists study DNA or RNA, they use millions of cells all mixed together. This is like reading a big book made from many copies, where all the small differences get hidden.

Single-cell sequencing lets scientists look at the DNA and RNA from just one cell. This helps them learn a lot about what that single cell does. The steps usually include:

• Finding and separating one cell.
• Taking out its DNA or RNA and making many copies.
• Getting the copies ready for sequencing.
• Reading the DNA or RNA sequence.
• Using computers to understand all the data.

It's much harder to study one cell than millions. Because there's so little material in a single cell, it's easy to lose parts, get contamination, or have the material break down. Also, scientists often need to make many copies of the DNA or RNA. This copying can sometimes make the results uneven or less accurate.

Why is Single-Cell Sequencing Important?

Even with these challenges, new improvements have made single-cell sequencing a powerful tool. It can help solve problems that were once very difficult. For instance, it can help us study:

• Samples with many different types of cells.
• Very rare types of cells.
• How cells are related to each other as they grow.
• Genetic differences in body tissues.
• Germs that are hard to grow in a lab.
• How diseases change over time.

Because it's so useful, single-cell sequencing was chosen as the "Method of the Year" in 2013 by Nature Publishing Group, a well-known science publisher.

How We Study DNA in Single Cells

Single-cell DNA genome sequencing is about taking one cell, copying all its DNA (or just a specific part), and then preparing it for special DNA reading machines. These machines include types like Illumina or Ion Torrent.

This method is used a lot to study normal body functions and diseases in animals and humans. By looking at single cells, scientists can find out if different cells in a tumor have different genetic changes. This can help understand how cancer grows or how it responds to treatment.

When studying tiny living things like bacteria, the DNA from a single organism is called a single amplified genome (SAG). Thanks to new progress in single-cell DNA sequencing, scientists can now collect DNA information from many tiny organisms that cannot be grown in a lab. Even though these SAGs might not be complete, new computer tools can help put together almost full DNA maps from them. The information learned from these tiny organisms might even help scientists figure out how to grow them in the lab in the future. Some computer programs used to put together these DNA maps include SPAdes, IDBA-UD, Cortex, and HyDA.

See also

• Single-cell analysis
• Single-cell transcriptomics
• Single cell epigenomics
• Tcr-seq
• DNA sequencing
• Whole genome sequencing