Marina Caillaud
Assistant Professor
Ph.D. Universite Paris-Sud (Orsay), France, 1994

Contact info:
  Biology Department (CNS 165)
  Ithaca College
  Ithaca, NY 14850
  USA
  Phone:  607-274-1181
  E-mail:  mcaillaud@ithaca.edu
 


COURSES TAUGHT AT ITHACA COLLEGE:

    Genetics (Spring, every year)
    Human Genetics (Fall, every year)
    Literature in Biology  (sometimes..)
 

FIELD OF SPECIALIZATION:

   Quantitative genetics/genomics, aphid genetics, insect behavior, insect-plant interactions.

RESEARCH INTERESTS

    I am interested in the genetics of ecologically important phenotypic traits that affect organisms� interactions with their biotic environment. Considerable variation within species or between species has been described for traits as different as feeding preferences, body morphology, or mating behavior. These traits have often been shaped by natural selection and became adaptations. What type of genes shape phenotypes as complex as behavior? How does nature fabricate adaptation? Are genes underlying adaptation mostly regulatory genes or structural genes? Are �adaptation genes� dedicated to a particular function or are they involved in other activities than the ones underlying ecological adaptations?
    None of the loci underlying ecologically important traits have been characterized at the molecular level. Genome-wide composite patterns of genetic (co)variance have been estimated for some populations, and a few Quantitative Trait Locus (QTL) mapping projects were published in the last 5 years. However, we are still far from a description of the particular nucleotide variation underlying any polymorphism in an ecologically important trait. Very few people are even considering this level of genetic resolution for natural populations and non-model organisms. Yet, this knowledge is likely to provide truly new insights into the evolutionary mechanisms and dynamics of the world�s most extravagant adaptations.
    I currently use pea aphids (Acyrthosiphon pisum Harris) as model systems for studying the genetics of ecologically important traits. Pea aphids have some very important logistic advantages for my purpose. First, the genome size is small (about 270Mb), as is the number of chromosomes (2n=8). Second, sexual forms can be produced on demand, yet the sexually produced progeny are parthenogenetic, facilitating replication during progeny testing without the necessity of inbreeding. Third, many characters show extreme intraspecific phenotypic variation in ecological traits. This is for instance the case for the character �resource use� as two hosts races (considered to be even incipient species by many researchers) using either alfalfa or red clover as host plant coexist. Intraspecific variation is usually preferable over interspecific variation because crosses can be made readily between different genotypes within a species, without the genomic incompatibilities that often impede crosses between species.
    Using quantitative (i.e. statistical) genetics, and genomics, I am in the process of mapping and characterizing at the molecular level two ecologically-important traits: host-plant specificity and variation in taste response.Most ecologically important traits are complex traits, and are influenced by more than many genes and the environment. Thus the use of a quantitative genetic approach is needed. I use genomic tools to compare genome wide patterns of gene expression in alternative phenotypes in order to identify genes that are differentially expressed. My objective is to clone, and ultimately sequence, the loci underlying phenotypic variation. Characterization of these loci will open the route to an analysis of how changes in gene expression effect a phenotypic change.
    The molecular characterization of the loci responsible for any ecologically important polymorphisms is obviously a major undertaking. Luckily, I am not the only one interested in having the necessary tools for identifying genes of ecological and evolutionary interest in aphids. Construction of these tools, i.e. for instance a high-resolution linkage map and mutation analysis, will take many years, many labs and many grants. Collaborative projects will be a key aspect of this endeavor.
Another important aspect of this endeavor will be the ability of researchers involved to develop an integrative approach. Genetics does not hold all the keys for understanding the evolution of ecologically important traits. In the case of the character �host specificity�, which I know most about, it became clear that incorporating behavior and chemical ecology in my project were essential, and I developed the necessary collaborations to do so (Alan Renwick, Boyce Thompson Institute; Marta del Campo, Bighamton University). And of course, a population genetics/ecological approach has to remain active, which it was through the work of other researchers on this system (Sara Via and Dave Hawthorne, University of Maryland). In the future, I believe that neurophysiological and developmental approaches will be essential.
 

PUBLICATIONS (undergraduate students in bold and underlined)

Braendle, C., M. C. Caillaud and D. L. Stern. Genetic mapping of aphicarus - a sex-linked locus controlling a wing polymorphism in the pea aphid (Acyrthosiphon pisum). Heredity, in press.

Braendle, C., I. Friebe, M.C. Caillaud and D.L. Stern. Genetic variation in an aphid wing polyphenisms is genetically linked to a naturally occurring wing polymorphism. Proc R Soc Lond B Biol. Sci., in press.

Huang, M. and M.C. Caillaud. Experimental evidence for inbreeding avoidance by recognition of close kin in the pea aphid, Acyrthosiphon pisum. Journal of Insect Behavior. Accepted.

          Caillaud, M.C., G. Mondor-Genson, S. Levine-Wilkinson, L. Mieuzet, A. Frantz, J.C. Simon and A. Coeur d�Acier, 2004. Microsatellite DNA markers for the pea aphid: Acyrthosiphon pisum (Harris, 1776) [Homoptera, Sternorrhynca]. Molecular Ecology Notes, vol. 4 (3) pp. 446-448. View pdf

Del Campo, M., S. Via and M.C. Caillaud. 2003.  Recognition of host specific stimulants mediates host specificity and assortative mating in two host races of the pea aphid.  Ecological Entomology 28/4, 405-412. View PDF.

Caillaud, C.M., M. Boutin, Christian Braendle and J.C. Simon, 2002. A sex-linked locus controls wing polymorphism in males of the pea aphid, Acyrthosiphon pisum (Harris). Heredity 89:346-352. View PDF.

 
Dedryver, C-A., M. Hulle, J.F. Le Gallic, M.C. Caillaud and J-C. Simon. 2001. Coexistence in space and time of different life-cycle variants of a cyclical parthenogen: the cereal aphid Sitobion avenae in France. Oecologia, 128, 379-388.
 
Caillaud, C.M. and S. Via. 2000. Specialized feeding behavior influences both ecological specialization and assortative mating in sympatric host races of pea aphids. The American Naturalist, 156 (6), 606-621. View PDF
 
  Caillaud, C.M. 1999. Behavioral correlates of genetic divergence due to host specialization in Acyrthosiphon pisum. Entomologia experimentalis et applicata, 91 (1), 227-232.
 
  Caillaud, C.M. & Rahbé, Y. 1999. Aposymbiosis in a cereal aphid : reproductive failure and influence on plant utilisation. Ecological Entomology, 24 (1), 111-114.

Di Pietro, J.P., Caillaud, C.M., Pierre, J.S. & Trottet, M. 1998 Sources of resistance to the cereal aphid Sitobion avenae in ancient species of Triticum. In. pp. 529-534, Aphids in managed and natural ecosystems. Ed by J. Nieto Nafria and A.F.G Dixon.

Di Pietro, J.P. & Caillaud, C.M., Chaubet, B., Pierre, J.S. & Trottet, M. 1998. Variation in resistance to Sitobion avenae (Sternorhynca: Aphididae) among diploid wheat genotypes : multivariate analysis of agronomic data. Plant breeding, 117/5, 407-412.

Di Pietro, J.P. & Caillaud, C.M., 1998. Response to intraclonal selection for adaptation to the resistant wheat Triticum monococcum in the English grain aphid Sitobion avenae. Environmental Entomology, 27 (1), 80-85.

Gianoli, E., Caillaud, C.M., Chaubet, B., Di Pietro, J.P. & Niemeyer, H.M., 1997. Variability in grain aphid (Homoptera: Aphididae) performance and aphid-induced phytochemicals responses in wheat. Environmental Entomology, 26 (3), 638-641

Plantegenest, M., Pierre, J.S., Caillaud, C.M., Simon, J.C., Dedryver, C.A. & Cluzeau, 1997. A model to describe the reproduction rate of the grain aphid, Sitobion avenae F. (Homoptera : Aphididae). European Journal of Entomology, 93 (4), 545-553.

Caillaud, C.M.  & Niemeyer, H.N., 1996. Possible involvement of the phloem sealing system in the acceptance of a plant as host by an aphid. Experientia, (52), 9, 927-931

Caillaud, C.M., Dedryver, C.A., Di Pietro, J.P., Fima, F., Simon, J.C. & Chaubet, B., 1995. Clonal variability in the response of Sitobion avenae (Homoptera : Aphididae) to resistant Triticum monococcum wheat lines. Bulletin of Entomological Research, 85, 189-195.

Caillaud, C.M., Di Pietro, Chaubet, B., & Pierre, J.S., 1995. Application of discriminant analysis to Electrical penetration Graphs of the aphid Sitobion avenae feeding on resistant and susceptible wheat. Journal of Applied Entomology, 119, 103-106.

Caillaud, C.M., Pierre, J.S., Chaubet, B. & Di Pietro, J.P., 1995. Analysis of wheat resistance to the cereal aphid Sitobion avenae using electrical penetration graph and flow charts combined with correspondence analysis. Entomologia experimentalis et applicata, 75, 9-18.

Caillaud, C.M., Dedryver, C.A. & Simon, J.C., 1994. Development and reproductive potential of the cereal aphid Sitobion avenae on resistant wheat lines (Triticum monococcum line). Annals of Applied Biology, 125, 219-232.

Pham-Delegue, M.H., Trouiller, J. Caillaud, C.M., Roger, B. & Masson, C., 1993. Effect of queen pheromone on worker bees of different ages: behavioural and electrophysiological responses. Apidologie, 24: 267-281.
 

 
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Last updated January, 2005