Isabelle Meusnier

Isabelle.Meusnier@oregonstate.edu

Phone:     (541) 867-0419

Research Interests:

I am a molecular geneticist. My current extension into population genetics is because of interests in phylogenetics studies, population structure and the dynamics of how this evolves.

During my PhD, I studied an invasive green alga (Caulerpa taxifolia) a newly introduced species in the Mediterranean Sea. The aim of my thesis was to determine the origin and genetic diversity of this alga. I developed a variety of molecular approaches to investigate variability at different hierarchical levels, from the distinction of different species to the relationships existing among different populations in the Mediterranean. I used the classical sequences of ITS and I developed an intron in the 16S to distinguish between species. For the biogeographic origin I developed SSCP on two DNA regions (nuclear and chloroplastic) and I analysed the bacterial flora associated with C. taxifolia that it can provide clues to the origin of the Mediterranean introduction. Two different approaches (allozymes and ISSR) are utilized to elucidate relationships among populations of C. taxifolia.

After my PhD, I was a “Junior Lecturer” (ATER) at the “Universite of Lille”. I mainly taught: genetics (Mendelian and population genetics), phylogeny and evolution. My research work was on the determinism of self-fertility in beet. The first step was to develop molecular markers link to self-fertility loci. My goal was to find AFLP markers using the BSA method.

Currently, my post doctoral project deals with resolving genetic differences among alternate life history types in Chinook salmon. I chose to stay in the marine environment but to work on fish to broaden my perspectives through working on mobile organisms. Chinook salmon (Oncorhynchus tschawytscha), like the other Oncorhynchus, is anadromous and semelparous. This species has a number of life history traits, such as the age of seaward migration; length of estuarine or oceanic residence; age of maturity; time of return to natal stream; and others. Some populations are in decline owing to environmental changes especially in river systems (water diversion, habitat deterioration, destruction of spawning grounds and overexploitation). Management of Chinook salmon is complicated by the fact that there are many life history types and often threatened and endangered populations coexist with other more stable populations when they may be at risk for loss (water diversion sites or fishery harvests). Life history identification through using molecular genetics poses a tool to quantify this loss. The first step in my work is to isolate and characterize new loci to discriminate between the different life history types in Chinook salmon. Once I have attained some of these, I will focus on genetic diversity within life history types to better understand the ecology of this species, population structure, migration, and gene flow. This will aid in the management of Chinook salmon populations, stock identification and conservation.

Publications:

Meusnier I, Valero M, Destombe C, Godé C, Desmarais E, Bonhomme F, Stam WT and Olsen JL, 2002. PCR-SSCP analyses of nuclear and chloroplast DNA provide evidence for recombination, multiple introductions and nascent speciation in the Caulerpa taxifolia complex. Molecular Ecology, 11, 2317-2325.

Meusnier I, Olsen JL, Stam WT, Destombe C and Valero M, 2001. Phylogenetic analyses of Caulerpa taxifolia (Chlorophyta) and of its associated bacterial microflora provide clues to the origin to the Mediterranean introduction. Molecular Ecology, 10, 931-946.

Olsen JL, Valero M, Meusnier I, Boele-Bos S and Stam WT, 1999. Reply to comment by Ghilshom and Jaubert. Journal of Phycology, 35, 441.

Olsen JL, Valero M, Meusnier I, Boele-Bos S and Stam WT, 1998. Mediterranean Caulerpa taxifolia and C. mexicana (Chlorophyta) are not conspecific. Journal of Phycology, 34, 850-856.

Meetings:

Stam WT, Meusnier I, Destombe C, Valero M and Olsen JL. Tracing invasions of Caulerpa taxifolia with molecular markers. Botany 2002. Madison, Wisconsin. August 2002.

Valero M, Meusnier I, Destombe C, Stam WT and Olsen JL. Origin and genetic diversity of the green alga Caulerpa taxifolia a newly introduced species in the Mediterranean Sea. Ministère de l’aménagement du territoire et de l’environnement. Séminaire de programme de recherche "Caulerpe et Invasions Biologiques". ENGREF – Paris 2001.

Meusnier I, Olsen JL, Stam WT, Destombe C and Valero M. Origin and genetic diversity of the green alga Caulerpa taxifolia a newly introduced species in the Mediterranean Sea. Ministère de l’aménagement du territoire et de l’environnement. Réunion de présentation des programmes de recherche "Caulerpe". Paris 1999.

Meusnier I, Olsen JL, Stam WT, Destombe C and Valero M. Origin and genetic diversity of the green alga Caulerpa taxifolia a newly introduced species in the Mediterranean Sea. XXIème réunion annuelle du Groupe de Biologie et Génétique des Populations. Rennes 1999.