Sean Carroll in Preposterous Universe:
In the question to understand the biology of life, we are (so far) limited to what happened here on Earth. That includes the diversity of biological organisms today, but also its entire past history. Using modern genomic techniques, we can extrapolate backward to reconstruct the genomes of primitive organisms, both to learn about life’s early stages and to guide our ideas about life elsewhere. I talk with astrobiologist Betül Kaçar about paleogenomics and our prospects for finding (or creating!) life in the universe.
More here.