Jaroslav Flegr

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Jaroslav Flegr
Jaroslav Flegr - portrait.jpg
Born (1958-03-12) 12 March 1958 (age 60)[1]
Prague, Czechoslovakia (now Czech republic)
Nationality Czech
Known for research into toxoplasmosis
Awards Ig Nobel Prize in Public Health (2014)
Scientific career
Fields Parasitology
Institutions Charles University in Prague

Jaroslav Flegr (born March 12, 1958) is a parasitologist, evolutionary biologist, and author of the book Frozen Evolution.[2] He is professor of biology at Charles University in Prague,[3] and is a member of the editorial board of the journal Neuroendocrinology Letters.[4]

His work on how toxoplasmosis—an infection caused by the protozoan parasite T. gondii—influences personality,[5] sex ratios,[6] and rates of traffic accidents,[7][8] has received coverage in The Atlantic,[9] Salon,[10] and The Guardian.[11] Flegr maintains that toxoplasmosis might increase the rate of traffic accidents by as much as one million collisions per year.[12][13][14] He also believes that T. gondii contributes to suicides and mental disorders such as schizophrenia.[9]

Frozen Evolution[edit]

Frozen Evolution is a popular science book which aims to explain current developments in evolutionary biology to a wide audience. It also contains information boxes which clarify important topics in science like peer review, scientific journals, citation metrics, philosophy of science, paradigm shifts, and Occam's razor. Flegr's previous research in toxoplasmosis is also mentioned.

The book also discusses Flegr's model of frozen plasticity, a hypothesis that describes a possible mechanism for the origin of adaptive traits. This hypothesis proposes that natural selection can only explain adaptation in limited conditions, for example when populations are genetically homogeneous. He describes frozen plasticity as being more general, and maintains that it better explains the origin of adaptive traits in genetically heterogeneous populations of sexual reproducing organisms.[15] His hypothesis of frozen plasticity is an extension of Niles Eldredge and Stephen Jay Gould's theory of punctuated equilibria,[16] which describes the history of most fossil species as being relatively stable for millions of years, later punctuated by swift periods of evolutionary change during speciation.

Personal life[edit]

Flegr is married and has two children as well as two cats.[17]


  • Jaroslav Flegr (2008). Frozen Evolution: Or, that's not the way it is, Mr. Darwin—Farewell to selfish gene (PDF). Prague: Charles University, Faculty of Science. ISBN 80-86561-73-9. (Czech version only in print)
  • Jaroslav Flegr (2009). Mechanisms of Evolution. Prague: Academia. (Czech version only in print)
  • Jaroslav Flegr; Jan Havlíček (1999). Changes in personality profile of young women with latent toxoplasmosis (PDF). Folia Parasitologica 46 (May): 22-28.


  1. ^ http://www.academia.cas.cz/autori/jaroslav-flegr.html
  2. ^ Hall, B.K. (2009). "A review of Frozen Evolution: Or That's Not the Way It is, Mr. Darwin, edited by Jaroslav Flegr". Evolution & Development. 11 (1): 126–129. doi:10.1111/j.1525-142X.2008.00310.x. Retrieved 2009-06-24.
  3. ^ Jaroslav Flegr University website
  4. ^ Board of Editors Neuroendocrinology Letters website
  5. ^ Flegr J (May 2007). "Effects of Toxoplasma on Human Behavior". Schizophr Bull. 33 (3): 757–60. doi:10.1093/schbul/sbl074. PMC 2526142. PMID 17218612.
  6. ^ Kanková S, Sulc J, Nouzová K, Fajfrlík K, Frynta D, Flegr J (February 2007). "Women infected with parasite Toxoplasma have more sons". Naturwissenschaften. 94 (2): 122–7. doi:10.1007/s00114-006-0166-2. PMID 17028886.
  7. ^ Flegr J, Havlícek J, Kodym P, Malý M, Smahel Z (July 2002). "Increased risk of traffic accidents in subjects with latent toxoplasmosis: a retrospective case-control study". BMC Infect. Dis. 2: 11. doi:10.1186/1471-2334-2-11. PMC 117239. PMID 12095427.
  8. ^ Flegr J, Klose J, Novotná M, Berenreitterová M, Havlícek J (2009). "Increased incidence of traffic accidents in Toxoplasma-infected military drivers and protective effect RhD molecule revealed by a large-scale prospective cohort study". BMC Infect. Dis. 9: 72. doi:10.1186/1471-2334-9-72. PMC 2692860. PMID 19470165.
  9. ^ a b McAuliffe, Kathleen (2012). "How Your Cat Is Making You Crazy." March issue.
  10. ^ Catherine Price. "Want a boy? Change the kitty litter". Salon.com. Retrieved 24 June 2009.
  11. ^ Adam, David (25 September 2003). "Can a parasite carried by cats change your personality?". London: The Guardian. Retrieved 24 June 2009.
  12. ^ "Cat bug link to 1m crashes". Edinburgh: Scotsman.com. 4 June 2009. Retrieved 24 June 2009.
  13. ^ "Czech scientists make unique finding on Rh factor effect". Prague Monitor. Archived from the original on 7 June 2009. Retrieved 24 June 2009.
  14. ^ Caroline Davis. "Times Higher Education - Findings: 'Harmless' bug may be killer". Times Higher Education Supplement. Retrieved 24 June 2009.
  15. ^ Flegr, Jaroslav (1999). Frozen Evolution: Or, That's Not the Way It Is, Mr. Darwin–Farewell to Selfish Gene. CIP Press (English translation).
  16. ^ Flegr, Jaroslav (1999). Frozen Evolution, pp. 141-146, 149-156.
  17. ^ McAuliffe, Kathleen (2012). How Your Cat Is Making You Crazy. March.

External links[edit]