Advances in sequencing technologies mean that we all have more data to work with than ever before, and this fosters collaborations. Working with genetic data now is really exciting; it feels like the field is moving forward and we are gaining more knowledge due to collaborative efforts. Also, working with other people always makes research more enjoyable.

What does the evolution of the mustard seed tell us about the evolution of humans?

The fact that the Old World and New World mustard seeds diverged around the time when we believe humans and animals were traveling across the Bering Strait Land Bridge gives us both a plausible answer for how Arabidopsis arrived in the New World so long ago (before, for example, it might have been transported by boat), and tells us that some migration to the New World of birds, animals, or humans was occurring around that time.

What do you think of the "Intelligent Design" issue?

First let me say that I'm interpreting "Intelligent Design issue" as the idea of teaching alternative theories to evolution by natural selection in biology classes.

What I enjoyed most in science classes during my primary education was learning how to make sense of the world around me. For example, learning how a rainbow is formed made that phenomenon more interesting to me, not less. I think that it is very important to learn in school what experts in a given field believe to be true. Biologists accept evolution by natural selection as the mechanism that generates the diversity of life we observe today, and thus I believe students should have to learn that in school as part of their biology curriculum.

Furthermore, I think evolution should be the organizing principle in biology courses. Unfortunately, I didn't even have a course like this until graduate school; we tend to learn first about water, the organelles of the cell, photosynthesis and cellular respiration, with evolution only towards the end. I think biology courses should begin with evolution and refer back to natural selection while explaining how different functional traits benefit different forms of life.

I also think it is very important for parents to talk to their children about what they learn in school, and to supplement their child's education at home. If parents want to discuss with their children evolution by natural selection and any implications it might have on their religious beliefs, they should do that at home, or students should discuss such ideas in a religion or philosophy class in school. But the place for that discussion is not in science class.

Do you encounter any opposition from religious groups that don't like you proving that evolution is a fact?

I haven't encountered opposition personally, but some groups have very creative interpretations of the results of my work, and they end up assuming my work concludes things they would like to believe instead of what it actually concluded. For example, I had a paper in 2005 that showed a positive correlation between genetic differences and geographic distance between globally-distributed indigenous populations; we used properties of this pattern to show that Africa had to be the origin of modern humans. One religious group then said that my work confirmed the biblical description of human origins by showing that all of mankind can be traced back to originating in one location from one man and one woman. This statement was a big leap from the conclusions in our paper! We said no such thing; we only were able to show the path man took when migrating out of Africa that makes the most sense, given the data we have today.