Quality-checking DNA Sequences

I have updates on my genetics work! I have tried amplifying all my snail tissue samples now (and in many cases, I've tried multiple times), and the ones that amplified I've sent off to be sequenced. I finally got the sequences back and now it's time to check them for quality! I had always wondered what files with DNA sequences looked like: perhaps a text file with As, Cs, Ts, and Gs? Perhaps visualized in some cool color scheme in a program I don't have?

It turns out the latter was closer to the truth—at least with the program I am using. In 4Peaks, you view the sequences as colored peaks, called a chromatogram, where each color is a different nitrogenous base. Yesterday I learned how to distinguish between a clearly defined sequence read and a messy read that can't be used in analyses because we won't be able to tell the bases apart. Here's what that looks like!

This is a very clear read and will be used to help me identify the snail species!

This is a poor read. You can see that in many cases, multiple colors are peaking. That means we don't know what base is at that site.