DUSTIN PENN |
| Assistant Research Professor |
| Department of Biology |
| University of Utah |
| Salt Lake City, UT 84112 |
| Phone: 801-581-8464
Email: Penn@biology.utah.edu |
GENERAL INTERESTS:
Evolutionary biology, behavioral ecology, and conservation biology.
RESEARCH INTERESTS:
Sexual selection, chemical signals, immunocompetence, kin recognition, and host-parasite coevolution.
CURRENT RESEARCH (JANUARY 1999)
I am collaborating with Wayne Potts and several students on experiments aimed to determine how natural selection maintains the highly polymorphic genes of the histocompatibility complex (MHC).
Experimental host-parasite coevolution. One hypothesis for MHC diversity is that it is the result of frequency-dependent selection imposed by evolving pathogens adapting to their host's MHC alleles. We are currently using serial passage experiments to determine whether pathogens are able to adapt to their host's MHC genes. We are also testing whether altering combinations of host MHC genes slows down the rate of pathogen adaptation to host genotypes (the "Red Queen" hypothesis) (Penn & Potts 1999 Am. Nat.).
Heterozygote advantage. A second hypothesis is that MHC diversity is driven by overdominant selection due to heterozygotes being more to infectious diseases than homozygotes. MHC heterozygotes present more antigens to the immune system than homozygotes, however, there is no experimental evidence that heterozygotes are more resistant. We are testing whether MHC-heterozygotes have an advantage to coinfections of different pathogens (Erin McClelland). We are also using computer simulations to determine whether a MHC-heterozygote advantage against various infectious agents (marginal overdominance) is sufficient to explain the diversity of MHC genes (Bradley Demarest).
Odor-mediated mating preferences. A third hypothesis is that MHC diversity is driven by disassortative mating preferences (reviewed in Penn & Potts 1999 Am. Nat.). MHC genes influence odor (Penn & Potts 1998 Physiol. Behav.) and mating preferences (Proc Roy Soc Lond) in house mice. Although much evidence indicates that genes in the MHC region influence odor and mating preferences in house mice (reviewed in Penn & Potts Adv. Immunol.), it is unclear whether these effects are due to classical MHC genes or some other linked genes. Therefore, we are currently examining the effects of classical MHC genes on odor and mating preferences (Lara Carroll). We are also investigating how mice learn the MHC-mediated odors of their nest mates early during development (chemosensory imprinting) (Penn & Potts Proc Roy Soc Lond.).
Inbreeding avoidance. MHC-dependent mating preferences may function to produce disease-resistant offspring or to avoid incest. The fitness consequences of inbreeding in the wild are unknown, but we have recently found experimental evidence using wild mice that inbreeding is much more detrimental than studies in colony conditions have found (Meagher, Penn, and Potts, Submitted). This means that there should be strong selection favoring the evolution of genetic inbreeding avoidance mechanisms.
Sexual selection and immunocompetence. Like other mammals, male house mice mark their territories with urine, and females are attracted to these scent marks. Females are able to recognize infected males by their odor, and females prefer the odor of uninfected males (Ethology). This may allow females to avoid direct transmission, but it may also allow them to obtain good genes for their offspring. To survive, males must invest resources into immunological defenses, but to reproduce they must invest into sexual displays and territorial defenses. It is likely that only high quality, genetically resistant males can do both, however (TREE). We are currently testing this "immunocompetence handicap hypothesis" using transgenic mice with impaired immune systems.
CURRENT GRANTS
| NIH grant: | "Selective Mechanisms Maintaining H-2 Polymorphisms." Co- investigator. | |
| NSF grant: | "Histocompatibility Genes and Sexual Selection." Co-investigator. | |
| University of Utah Research
Incentive Seed Grant: | "Predicting and Retarding the Evolution of Infectious Diseases." Co-investigator. |
PAPERS AND BOOKS
MHC genes, odor, and mating preferences
Penn, D. and W. Potts. 1999. The evolution of mating preferences and major histocompatibility complex genes. American Naturalist 153(2): 145-164. view PDF version
Penn, D. and W. Potts. 1998. MHC-disassortative mating preferences reversed by cross-fostering. Proceedings of the Royal Society of London, B. 265, 1299-1306.
Penn, D. and W. Potts. 1998. Untrained mice discriminate MHC-determined odors. Physiology and Behavior. 64(3), 235-243.
Penn, D. and W. Potts. 1998. How do major histocompatibility genes influence odor and mating preferences? Advances in Immunology, 69, 411-435.
Apanius, V., Penn, D., Slev, P., Ruff, R., and Potts, W. 1997. The nature of selection on MHC genes. Critical Reviews in Immunology, 17, 179-224.
Chemical signals and parasite-mediated sexual selection
Penn, D. and W. Potts. 1998. Chemical signals and parasite-mediated sexual selection. Trends in Ecology and Evolution. 13(10), 391-396.
Penn, D., G. Schneider, K. White, P. Slev and W. Potts. 1998. Influenza infection neutralizes the attractiveness of male odor to female mice (Mus musculus). Ethology. 104, 685-694.
Popular articles written on our sexual selection work
Anon. 1997. Darwin revisited: the sexual behaviour of animalsÐincluding humans mates. The Economist, August, 59-61.
Alison Motluk. 1997. Best mates. New Scientist, September, 6.
Girard Morice. 1998. L'odeur de la grippe (The odor of the flu), Science & Vie, November, 40.
Inbreeding depression
Meagher S., D.J. Penn, and W.K. Potts. 2000. Male-male competition magnifies inbreeding depression in wild house mice. Proc. Nat. Acad. Sci. 97:3324-3329view PDF version
Educational writing on MHC and host-parasite coevolution
Penn, D. In review. The Evolution of Immunological Defenses. In An Introduction to Biology, Eds. Moore, M. and Moore, J. McGraw-Hill publishers.
Penn, D. In review. Host-Parasite Coevolution. Encyclopaedia of Life Sciences. Macmillan Reference Limited, Stockton Press.
Penn, D. In review. Major Histocompatibility Genes (MHC). Encyclopaedia of Life Sciences. Macmillan Reference Limited, Stockton Press.
Penn, D. In review. Major Histocompatibility Genes (MHC): Humans. Encyclopaedia of Life Sciences. Macmillan Reference Limited, Stockton Press.
Darwinian Ecology
Penn, D. 1999. Explaining demographic transition. Trends in Ecology and Evolution. 14(1): 32.
Penn, D. and Mysterud, I. (Editors) In prep. Evolutionary Perspectives on Environmental Problems: A Reader
Penn, D. In prep. Darwinian Ecology: the Evolutionary Roots of Our Environmental Problems.
RELATED WEBSITES
Mice: http://www.rodentia.com/wmc/index.html
Animal Behaviour Society: http://www.animalbehavior.org/ABS/index.phtml
Chemical communication: http://evolution.anthro.univie.ac.at/institutes/urbanethology/pheropro.html
Immunology: http://www.looksmart.com/r?lm&/eus1/eus317837/eus317920/eus53956/eus5485 9/eus83453/eus329791
Evolution: http://infoseek.go.com/WebDir/Science/Evolution?sv=IS&svx=related
Host-parasite coevolution: http://www.unibas.ch/dib/zoologie/ebert/hostpara.html
Evolution of infectious diseases: http://www.theatlantic.com/issues/99feb/germs.htm
Darwinian medicine: http://www.sciam.com/1998/1198issue/1198nesse.html
Human Behavior and Evolution Society: http://157.242.64.83/hbes.htm