Minute to Understanding: DNA 101

DNA? Genes? Genomes? What? Don't worry. If you're confused, just board the DNA to genome express train.

Picture a train track. Each railroad tie represents the smallest building block of DNA, a base pair. There are two types of base pairs, A and T, and G and C, and they're shuffled all along the track in a unique sequence. String all these bases together and you have DNA.

Now, picture a train car. The car spans a certain number of railroad ties, a unique DNA based sequence. That is a gene. A gene controls a certain characteristic, like green eyes. Here comes the rest of the train, each car a different gene, and each controlling a different characteristic.

Now picture the entire train route. All along this route are many trains. This is what a chromosome looks like. Humans have 23 chromosomes, 23 train routes say. From all the way up here we can see all 23 routes at once. This is a genome.