I am a wet lab person moving towards programming, an Arabidopsis scientist going for non-model species, a real-time experimenter dusting off herbarium specimen.
Drivers are a love for knowledge, plants, and how small things together form a larger picture.
Stomata-related adaptation to environmental change
Stomata, plant pores that facilitate efficient photosynthesis, and whose density and size reflect environmental conditions, are a likely target of climate change adaptation. They are also highly preserved in herbaria, and in the model plant Arabidopsis thaliana, their developmental and functional pathways are well understood and easily manipulable using a plethora of molecular tools. As an HFSP fellow, I currently study adaptation-related genetic variation in functionally verified stomata genes such as the transcription factor SPEECHLESS. To identify stomata-related local adaptation and historically lost genetic variation that may be adaptive in certain conditions, I analyze variation in both contemporary and >190 historical A. thaliana genomes (incl. 120+ new genomes, in collaboration with Lua Lopez, CSUSB and Jesse Lasky, Penn State; Lopez, Lang et al. unpublished). While overall the genes at the core of stomatal development have low genetic variation, select genes do display genetic variants that are both associated with climate parameters, and whose frequencies vary over time. Ultimately, I will characterize the molecular and phenotypic effects of these variants experimentally, to gain insights into actual changes in stomatal characteristics over time, potentially following environmental change. In addition, I use experimental knowledge on the effect of mutations in stomata development genes to build a genetics-based proxy for stomatal density (akin to a functionally-experimentally informed polygenic risk score) that shows historical density shifts as predicted by climatic change (Lang et al. unpublished).
To connect historical genotypes with phenotypes, I am also currently building a database of hundreds of A. thaliana herbarium specimen genomes and stomata characteristics. To this end, in parallel to working at Stanford, I became a Research Associate at the California Academy of Sciences, where I coordinated loans of herbarium specimens from multiple European herbaria.
Genetic change in non-model plant species following global change
Global change is the largest evolution experiment of all times. Witnesses that are particularly exposed to fluctuations in climate, or land use, are plants. To understand where, how, and to which end, they are reacting — adapting? — I study changes in genetic variation in three non-model species within the last ~200 years, using a combination of contemporary and historic samples. Traditionally, non-model species analysis uses reduced representation sequencing approaches such as Restriction Associated DNA sequencing (RADseq). However, the ancient-DNA typical DNA fragmentation prevents use of this method for herbarium specimens. To circumvent this problem and compare historical and modern samples, I refined a hybridization-based capture method (hyRAD) that allows enriching historical ancient DNA libraries for the same fraction of the genome represented in modern RADseq libraries (Lang et al. 2020, Mol Ecol Res). This method allows reduced representation sequencing of historical samples independent of their genome size, ploidy level, and the presence of a reference genome.
Combining RADseq and hyRAD, I have now processed ~1000 contemporary and ~300 historic samples of the early-flowering species Alliaria petiolata, Cardamine bulbifera and Ficaria verna. In these datasets, I have identified patterns of genetic diversity change over time, and found that for at least one of the species, there may be a genetic base for its accelerated spring flowering (Lang et al., unpublished).
Both projects are part of the DFG-funded German Biodiversity Exploratories, a long-term, large-scale biodiversity and ecosystem research effort that has been running since 2006.
Non-coding RNAs in evolution
Having turned from basic molecular biology to temporal-scale evolutionary perspectives, I ultimately aim at combining the two. Small molecules with big roles have always fascinated me — think the effects of non-coding regulatory factors, like small RNAs; hence also my miRNA-focused PhD work. One of the questions I am now curious about is the role of sRNAs, particularly miRNAs, in the context of adaptation and evolution. How do rapid birth and turnover of sRNAs, or regulation of their biogenesis and function factors, contribute to adaptation to new environmental challenges? How conserved are such adaptation mechanisms and their building blocks?
Beyond – Grammar of Life
In- and outside of the lab, I am fascinated by all aspects of language, and juggling with grammar, words and punctuation. How a purposeful combination and succession of words, commas and dots becomes more than the ‘sum of all parts’. Ultimately, biological organisms follow similar principles: Growth, development and homeostasis are largely based on differential regulation of transcription, and translation, both per se already language-references — alas, the language-parallel is not new. As I, besides biology, believe in the power of words, and the importance of communication, I am working on skills to combine both. I want to help translate what we know to a language that everybody can understand.