Scientists have come to understand that microscopic and single celled organisms have completely dominated Earth's systems and cycles throughout evolutionary history. EAPS newest Crosby postdoctoral fellow Lily Momper is trying to understand how and when they became able to do that.
Momper says she has been interested in environmental microbiology, or how we interact with our environment since she was very, very little. Growing up on a farm in southern Missouri she says her father was always experimenting with what plants and trees he could get to grow there, and in particular how he could grow them better or more efficiently. "I think that was what originally inspired in me a curiosity about how our environment actually works, how we interact with it, and the basics of scientific experimentation" Momper tells me. "As I grew older and learnt more biology, I discovered the dominant role single celled organisms play on our planet and so, increasingly, I found myself wanting to understand more about these outsized players in Earth's environment."
Momper went to Washington University in St Louis to do an undergraduate degree in biology. She says, "They had great plant biology and especially plant biochemistry programs and these deepened by fascination with how photosynthesis works and the mechanisms underlying how plants grow and reproduce." A passion to specialize in environmental microbiology, ultimately propelled Momper to the University of Southern California and a PhD in molecular and microbiology. At USC, somewhat by chance, Momper found herself in a laboratory that was part of NASA's Astrobiology Institute. This distributed research organization established in 1998 by NASA "to develop the field of astrobiology and provide a scientific framework for flight missions" has a sister "node" in EAPS at MIT Origins of Complex Life, and it was through this connection that Momper met EAPS professors Roger Summons, Tanja Bosak, and Greg Fournier and came up with the postdoctoral fellowship proposal that secured the Crosby Fellowship for her.
"My research focuses on using bacterial genome sequencing in the geologic past to constrain the dates when crucial metabolisms arose, for example oxygenic photosynthesis, the metabolism that has allowed complex life (including of course humans), to arise on our planet. Going back even further in time, we are also looking to pin down the advent of phototrophy, the metabolism used by every single green plant on our planet today, but originally, billions of years ago, a bacterial metabolism," Momper explains.
So how can we use modern bacterial genomes to understand what happened billions of years ago? "Typically we might think of evolutionary history as being recorded in the rock record, and it is, however evolutionary history is also recorded in the DNA and genome sequences of ancient bacterial lineages," explains Momper. "Greg Fournier is a pioneer of this kind of genome based molecular dating. Genome sequences can be used as a chronological map or puzzle within which we can date evolutionary events. I'm attempting to grow bacteria in the laboratory that we think were responsible for these world changing metabolisms - our likely candidates - and work with Fournier to develop tools and techniques for sequencing their genomes."
Momper's goal is to be able to take whole genomes and compare them against other distantly related bacterial genomes, ancient deeply branching lineages, and through that comparison constrain dates for the advent of each class of metabolisms
Next-generation genome sequencing has caused the amount of data available data to snowball. "The real challenge in my project, and in the whole field of genomic analysis right now, is the number of genome sequences available has far outstripped the capacity of the bioinformatic tools needed to unlock the information encoded there. Greg Fournier is a pioneer in this - which is a key reason why I wanted to work with him to understand how to utilize the data I am gathering as efficiently and effectively as possible.
Momper says she is definitely very grateful for the opportunity the Crosby Fellowship is giving her. "It was a huge surprise when I found out that I had received the fellowship. So far it has been a really excellent experience and I am very excited to see what the next two years bring."
"I only arrived in September but I love being at MIT. The EAPS floor of Building E25 houses six labs each doing different research, all within the planetary sciences, and the conversations that you end up having just in the hall way or at lunch are so stimulating and diverse. It doesn't always have to be about science, but there's always a fresh idea to be talked about. I have also found that the support here for the postdoctoral community is really astonishing. It's the best I've experienced. I think that MIT supports their graduate students and their postdocs really, very well."
The W. O. Crosby Postdoctoral Fellowship supports exceptional early-career scientists with research interests in the fields of geology, geochemistry, or geobiology. Crosby Fellows pursue independent research but typically also collaborate with one or more researchers in the department.