EEB Seminar – Nov. 24th

This week EEB welcomes Dr. Melania Cristescu from McGill University:

From barcoding single individuals to metabarcoding biological communities: Towards understanding and managing invasive species


Estimating biodiversity has been a central undertaking and a major challenge for biologists over the centuries. The DNA-based species identification known as barcoding, firmly transformed the traditional approach to biodiversity science. The field is quickly transitioning from barcoding single individuals to metabarcoding complex communities of organisms. This rapid evolution involves new sequencing technologies, bioinformatics pipelines, computational infrastructure, and experimental designs. All these changes require new, integrative and coordinated approaches to delineate species and interpret biodiversity estimates. In this dynamic genomics landscape, many metabarcoding studies remain insular; biodiversity estimates depend on the particular marker of choice, the quality of the DNA libraries, bioinformatics pipelines, and divergence thresholds implemented. The molecular operational taxonomic units (MOTUs) inferred are not easily recognizable across sites or studies making inferences regarding species distributions or ecology less practical. The research community needs a robust recognition system open to input, validation, and annotation from users. A coordinated advancement of DNA-based species identification that integrates taxonomic information, phylogenetic inferences with barcoding information would facilitate access to almost three centuries of taxonomic knowledge and one decade of building repository barcodes. Many conservation projects are time sensitive, research funding is becoming restricted and informed decisions depend critically on our ability to embrace an integrative approach to biodiversity science. Using metabarcoding approaches calibrated on mock communities, we were able to detect distinct biodiversity signatures in natural zooplankton communities, and to identify non-indigenous species that had not previously been reported.


  • Born in Transilvania, Romania
  • Conducted undergraduate studies at the University of Constanta Romania, at the Black Sea coast. First undergraduate project focused on the invasive ctenophore Mnemiopsis Leidyi.
  • 1999 started PhD at the University of Guelph under the supervision of Paul Hebert. Central research on Speciation Patterns and Processes in Ancient Lakes
  • 2003 started the PostDoc stage at Indiana University with Michael Lynch. Main projects centered on developing Daphnia pulex as a model for ecological genomics.
  • 2006 took my First Faculty position at the Great Lakes Institute for Environmental Research, University of Windsor. Launched the NSERC CREATE training program in Aquatic Ecosystem Health.
  • 2012 Moved to McGill University. Received the CRC chair in Ecological Genomics
  • 2013 Became Co-Editor in Chief for the journal Genome (Canadian Science Publishing).

I have made significant contributions to research in three main areas: 1) the nature and scale of recombination and mutation rate variation across genomes; 2) the genetics of aquatic invasions; and 3) speciation in ancient lakes.

Recent Representative publications:

Chain FJJ, Brown EA, MacIsaac HJ, Cristescu ME (2016) Metabarcoding reveals strong spatial structure and temporal turnover of zooplankton communities among marine and freshwater ports. Diversity and Distributions, 22, 493-504.

Brown EA, Chain FJJ, Zhan A, MacIsaac HJ, Cristescu ME (2016). Early detection of aquatic invaders using metabarcoding reveals a high number of non-indigenous species in Canadian ports, Diversity and Distributions, 22, 1045-1059.

Cristescu ME (2015) Genetic reconstructions of invasion history. Molecular Ecology, 24, 2212-2225.

Flynn JM, Brown EA, Chain FJJ, MacIsaac HJ, Cristescu ME (2015) Towards accurate molecular identification of species in complex environmental samples: testing the performance of sequence filtering and clustering methods. Ecology and Evolution, 5, 2252-2266.

Cristescu ME (2014) From barcoding single individuals to metabarcoding biological communities: towards an integrative approach to the study of global biodiversity. Trends in Ecology and Evolution 29, 566-571.

Xu S, Innes DJ, Lynch M, Cristescu ME (2013) The role of hybridization in the origin and spread of asexuality in Daphnia. Molecular Ecology, 22, 4549-4561.

Zhan A, Hulak M, Syvester F, Huang X, Abisola AA, Abbott CL, Adamowicz SJ, Heath DD, Cristescu ME, MacIsaac HJ (2013) High sensitivity of 454 pyrosequencing for detection of rare species in aquatic communities. Methods in Ecology and Evolution, 4, 558-565.

The EEB Seminars run weekly, on Thursdays, in the EEB Lounge of the BioSciences Complex, Room 4338, from 12:30-1:30pm. Light refreshments are served starting at 12:15.

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