title: "Everything you always wanted to know about sex (but were afraid to ask)" in Leishmania after two decades of laboratory and field analyses.
abstract: Leishmaniases remain a major public health problem today (350 million people at risk, 12 million infected, and 2 million new infections per year). Despite the considerable progress in cellular and molecular biology and in evolutionary genetics since 1990, the debate on the population structure and reproductive mode of Leishmania is far from being settled and therefore deserves further investigation. Two major hypotheses coexist: clonality versus sexuality. However, because of the lack of clear evidence (experimental or biological confirmation) of sexuality in Leishmania parasites, until today it has been suggested and even accepted that Leishmania species were mainly clonal with infrequent genetic recombination (see [1] for review). Two recent publications, one on Leishmania major (an in vitro experimental study) and one on Leishmania braziliensis (a population genetics analysis), once again have challenged the hypothesis of clonal reproduction. Indeed, the first study experimentally evidenced genetic recombination and proposed that Leishmania parasites are capable of having a sexual cycle consistent with meiotic processes inside the insect vector. The second investigation, based on population genetics studies, showed strong homozygosities, an observation that is incompatible with a predominantly clonal mode of reproduction at an ecological time scale (approximately 20-500 generations). These studies highlight the need to advance the knowledge of Leishmania biology. In this paper, we first review the reasons stimulating the continued debate and then detail the next essential steps to be taken to clarify the Leishmania reproduction model. Finally, we widen the discussion to other Trypanosomatidae and show that the progress in Leishmania biology can improve our knowledge of the evolutionary genetics of American and African trypanosomes.
authors.affiliation: Génétique et Evolution des Maladies Infectieuses, IRD/CNRS/UM1 (UMR 2724), Montpellier, France. rougeron.virginie@gmail.com
authors.forename: Virginie
authors.initials: V
authors.lastname: Rougeron
authors.forename: Thierry
authors.initials: T
authors.lastname: De Meeûs
authors.forename: Sandrine
authors.initials: S
authors.lastname: Kako Ouraga
authors.forename: Mallorie
authors.initials: M
authors.lastname: Hide
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Bañuls
mesh_terms: D007891:Leishmania / Q000502:physiology*; D012098:Reproduction
references.citation: Clin Microbiol Rev. 1999 Jan;12(1):126-46
references.pmid: 9880478
references.citation: Cell Mol Life Sci. 2007 Jun;64(11):1355-72
references.pmid: 17396223
references.citation: Science. 2009 Jun 26;324(5935):1644
references.pmid: 19556486
references.citation: Int J Parasitol. 2006 Nov;36(13):1383-8
references.pmid: 16930606
references.citation: Mem Inst Oswaldo Cruz. 2004 Feb;99(1):1-12
references.pmid: 15057339
references.citation: Parasite. 2008 Sep;15(3):455-7
references.pmid: 18814722
references.citation: Trends Parasitol. 2002 Sep;18(9):405-10
references.pmid: 12377258
references.citation: Infect Genet Evol. 2004 Dec;4(4):345-51
references.pmid: 15374532
references.citation: Adv Parasitol. 2007;64:1-109
references.pmid: 17499100
references.citation: PLoS Pathog. 2009 May;5(5):e1000410
references.pmid: 19412340
references.citation: Infect Genet Evol. 2007 Dec;7(6):675-84
references.pmid: 17704009
references.citation: Trends Ecol Evol. 1996 Feb;11(2):41-6
references.pmid: 21237759
references.citation: Parasitology. 1989 Dec;99 Pt 3:391-402
references.pmid: 2575239
references.citation: Science. 2009 Apr 10;324(5924):265-8
references.pmid: 19359589
references.citation: Parasitol Today. 1992 May;8(5):174-7
references.pmid: 15463609
references.citation: Microbes Infect. 2007 Mar;9(3):334-43
references.pmid: 17307010
references.citation: Proc Natl Acad Sci U S A. 1990 Apr;87(7):2414-8
references.pmid: 2320563
references.citation: Heredity (Edinb). 2010 Feb;104(2):135-40
references.pmid: 19812614
references.citation: Mol Biochem Parasitol. 2007 Jan;151(1):133-6
references.pmid: 17134768
references.citation: Nature. 1986 Jul 10-16;322(6075):173-5
references.pmid: 3724860
references.citation: Annu Rev Phytopathol. 1996;34:457-77
references.pmid: 15012552
references.citation: Hereditas. 1987;107(1):95-101
references.pmid: 3429255
references.citation: J Eukaryot Microbiol. 1997 Sep-Oct;44(5):408-11
references.pmid: 9304809
references.citation: Parasit Vectors. 2009 Sep 21;2(1):43
references.pmid: 19772562
references.citation: Proc Natl Acad Sci U S A. 1993 Feb 15;90(4):1599-603
references.pmid: 8381972
references.citation: Nucleic Acids Res. 2005 Nov 27;33(21):6688-93
references.pmid: 16314301
references.citation: Parasitol Today. 1993 Feb;9(2):58
references.pmid: 15463709
references.citation: Science. 2000 May 19;288(5469):1211-5
references.pmid: 10817991
references.citation: Proc Natl Acad Sci U S A. 2000 Nov 21;97(24):13442-7
references.pmid: 11078512
references.citation: Parasitology. 2000 May;120 ( Pt 5):513-26
references.pmid: 10840981
references.citation: Parasit Vectors. 2008 Feb 25;1(1):4
references.pmid: 18298832
references.citation: Infect Genet Evol. 2007 Mar;7(2):308-32
references.pmid: 16949350
references.citation: Proc Natl Acad Sci U S A. 2009 Jun 23;106(25):10224-9
references.pmid: 19497885
references.citation: Mol Biochem Parasitol. 1992 Feb;50(2):197-204
references.pmid: 1311052
references.citation: Acta Trop. 1995 Aug;59(4):293-307
references.pmid: 8533665
references.citation: J Parasitol. 1995 Jun;81(3):395-403
references.pmid: 7776124
references.citation: Proc Natl Acad Sci U S A. 2001 Jun 5;98(12):6720-4
references.pmid: 11381112
references.citation: Am J Trop Med Hyg. 2007 Mar;76(3):573-8
references.pmid: 17360886
references.citation: Proc Natl Acad Sci U S A. 2001 Jun 19;98(13):7396-401
references.pmid: 11416213
references.citation: Nature. 2003 Feb 27;421(6926):936-9
references.pmid: 12606999
references.citation: Trends Parasitol. 2002 Feb;18(2):81-5
references.pmid: 11832299
references.citation: Mol Biochem Parasitol. 2005 Sep;143(1):12-9
references.pmid: 15941603