Michael Nowak

Image of Michael Nowak
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Phone +47-22851750
Mobile phone +47-91386679
Room 112B Botanical museum
Username
Visiting address Sars gate 1 None 0562 OSLO
Postal address Postboks 1172, Blindern 0318 OSLO

Background

  • Ph.D. Biology, 2010, Duke University Department of Biology
  • M.S. Botany, 2004, University of Oklahoma Department of Botany and Microbiology
  • B.S. Biology 2002, University of Wisconsin-Stevens Point Department of Biology

Previous Appointments

  • Postdoctoral Research Fellow, 2014 - 2015, SciLifeLab, University of Stockholm, Sweden
  • Oberassistant, 2011– 2014, Institute of Systematic Botany, University of Zürich, Switzerland

Research

I am a plant evolutionary biologist using modern research methods to explore the fundamental processes responsible for generating Earth’s spectacular biological diversity. Specifically, my work aims to understand the causes and consequences of mating system evolution and the process of species divergence in plants. By leveraging modern DNA sequencing technologies and a diverse toolbox of analytical approaches including de novo genome assembly, quantitative genetics, population genomics, phylogenetic analysis, and bioinformatics, my research is expanding our knowledge of the genetic basis of plant evolution. 

Plant Mating System Evolution

Mating systems in plants are expressed through a variety of genetic and morphological mechanisms that have significant impacts on the genetic structure and diversity of populations. Despite the prevalence and importance of such mechanisms in the flowering plants, very little is known about the identity and function of genes that determine mating types. In my research, I work toward understanding the function and evolution of mating type loci and the evolutionary consequences of the mating system shifts that result from mating type loci disfunction. During my PhD research, my work was focused on characterizing the self-incompatibiliity locus functioning in coffee trees (genus Coffea, Rubiaceae; Nowak et al. 2011). By comparing the diversity of self-incompatibility alleles in Mauritian versus Madagascan and African coffee trees, we were able to estimate the size of the population that likely colonized that volcanic island approximately 2 million years ago (Nowak et al. 2014). My future work along these lines is focused on identifying the phylogenetic extent of this self-incompatibility system in the coffee family (Rubiaceae), and characterizing the function and diversity of the male component of the coffee self-incompatibility mechanism.

Since I finished my PhD, my mating system research has expanded to using modern tools of genomics to characterize the genetic basis of a type of self-incompatibility called distyly in the primroses (Primulaceae). Distyly is a system in which a population is composed of two hermaphroditic floral morphs and inter-morph reproduction is the only viable mode of reproduction. Using a de novo genome assembly and comparative transcriptomics, we were able to identify a set of candidate genes for this floral polymorphism in the cowslip, Primula veris (Nowak et al. 2015). I am currently expanding this experimental strategy to include a larger set of distylous plants from a diversity of flowering plant families in order to evaluate the various functional paths that different plant lineages have taken to evolve this relatively common mating system. 

Plant Speciation Genetics

Speciation is the process in which one species splits into two. The spectacular diversity of organisms existing today on Earth and countless species that have since gone extinct owe their origins to this process. Despite the clear importance of this process in generating biodiversity, we know very little about the genetic mechanisms responsible for keeping two recently diverged species from freely interbreeding, thus maintaining their respective reproductive isolation. My speciation research is a part of the SpArc project at the UiO Natural History Museum, in which we aim to use quantitative genetics and de novo genome assembly to identify the genetic architecture of reproductive isolation between recently diverged Alaskan and Norwegian populations of Draba nivalis and Cochlearia groenlandica, respectively. 

Moving beyond the Arctic, we are also conducting a massive inter-regional crossing experiment with the aim of identifying population genetic and demographic parameters that might impact the rate of evolution of reproductive barriers within species. This experiment is focused on diverse sample of the Mediterranean members of the mustard family (Brassicacea) and has the overarching aim of identifying universal patterns involved in the accumulation of reproductively isolated lineages within species, which are often called cryptic species.

Software Development

SNAPE - Single Node Age Prior Estimator

This software tool was developed to calculate informative divergence time priors based on a relatively complete assessment of the fossil record of a single clade of interest. Such prior distributions can be implemented in most popular molecular divergence time estimation packages. The user must provide the stratigraphic ranges of fossil lineages belonging to the clade of interest and an estimate of the extant standing diversity of this clade. See Nowak et al. (2013) for more information about the theoretical framework and analytical approach. SNAPE is open source freeware and available for download here.

Publications

  • Nowak, MD, G Russo, R Schlapbach, M Lenhard, CN Huu, E Conti. 2015. The draft genome of Primula veris yields insights into the molecular basis of heterostyly. Genome Biology 16:12.
  • Nowak, MD, BC Haller, AD Yoder. 2014. The founding of Mauritian endemic coffee trees by a synchronous long-distance dispersal event. Journal of Evolutionary Biology, 27:1229-1239.
  • Nowak, MD, C Simpson, AB Smith, and DJ Zwickl. 2013. A simple method for estimating informative node age priors for the fossil calibration of molecular divergence time analyses. PLoS ONE, 8(6): e66245.
  • Nowak, MD, AP Davis, and AD Yoder. 2012. Sequence data from new plastid and nuclear COSII regions resolves early diverging lineages in Coffea (Rubiaceae). Systematic Botany, 37(4):995-1005.
  • Nowak, MD, AP Davis, F Anthony, and AD Yoder. 2011. Expression and trans-specific polymorphism of self-incompatibility RNases in Coffea (Rubiaceae). PLoS ONE, 6(6): e21019.
  • Yoder AD, and MD Nowak. 2006. Has Vicariance or Dispersal been the Predominant Biogeographic Force in Madagascar? Only Time will Tell. Annual Review of Ecology, Evolution, and Systematics, v.37.

See Michael Nowak's Google Scholar profile for a complete listing of my publications and citation metrics.

Published Aug. 7, 2014 2:52 PM - Last modified Oct. 6, 2015 12:33 PM