Genetics of Viking Metal, part 2 - Mitochondria

I know you are dying to find out what Viking metal could possibly be, but we have to cover something else first. I am not making this up.

My previous post explained that DNA on the male-only Y chromosome is not as mixed around from generation to generation as DNA on the other chromosomes. I also told you that DNA gets all chopped up when chromosomes are formed for egg cells.

Don't get concerned about gender issues. Women also pass along relatively unmixed DNA exclusively to their daughters. Hold on a minute, didn't I just say that female DNA on chromosomes gets all mixed up every generation? How can there be unmixed DNA? Simple, it's not on chromosomes. We have two sets of DNA.

“Hold on, Rock Dad. I thought our chromosomes contained all the DNA we need.” Sort, of. This is where it gets a little sci-fi.

Let’s talk about mitochondria. Mitochondria are separate structures inside our cells that do a whole bunch of important things. Mitochondria have their own DNA. What’s freaky is that their DNA doesn’t look like human DNA. It looks like bacteria DNA. For this and other reasons, some researchers think that mitochondria originally were bacteria that became part of cells. This goes way beyond the Egyptian plover eating parasites on a crocodile’s body in exchange for “safe passage” and protection from predators. The bacterium actually became part of us and now we need each other to live. The story is really cool and would be a good topic for a future blog entry. Remind me, some day.

Sperm and egg cells both have mitochondria. The sperm’s mitochondria die soon after fertilization, so 100% of everybody’s mitochondria comes directly from their mothers. Females pass on their maternal grandmother’s mitochondrial DNA. Males don’t pass on anybody’s mitochondrial DNA.

This means that mitochondrial DNA are a link back to the mitochondrial DNA of our female ancestors. It gives us another way to track our development.

Time to wrap up. Soon I will get into how the DNA changes over many generations and what those changes tell us. We will learn about Viking Metal and I just might touch on something about hip-hop before we are through.

Sit tight and rock on.

Genetics of Viking Metal, Part 1