Question special

First of all thank you to all of our panelists for taking part in this important discussion. I hope you’re all looking forward to the conversation over the next few days as much as we’re looking forward to following along. Over the next 10 days the moderators and I will be posting a daily general theme along with a starting question for that day. We strongly encourage our panelists and readers to jump in and ask their own questions on the day’s theme as well. Themes will range from ethics to research and from law to public health.

Today the theme is "background" to help introduce our readers to the topic, and I’ll be posting a couple extra questions. So the first question—what is mitochondrial donation?