"Everything you always wanted to know about sex (but were afraid to ask)" in Leishmania after two decades of laboratory and field analyses.
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.
Rougeron
Virginie
V
Génétique et Evolution des Maladies Infectieuses, IRD/CNRS/UM1 (UMR 2724), Montpellier, France. rougeron.virginie@gmail.com
De Meeûs
Thierry
T
Kako Ouraga
Sandrine
S
Hide
Mallorie
M
Bañuls
Anne-Laure
AL
D007891:Leishmania / Q000502:physiology*; D012098:Reproduction
Clin Microbiol Rev. 1999 Jan;12(1):126-46
9880478
Cell Mol Life Sci. 2007 Jun;64(11):1355-72
17396223
Science. 2009 Jun 26;324(5935):1644
19556486
Int J Parasitol. 2006 Nov;36(13):1383-8
16930606
Mem Inst Oswaldo Cruz. 2004 Feb;99(1):1-12
15057339
Parasite. 2008 Sep;15(3):455-7
18814722
Trends Parasitol. 2002 Sep;18(9):405-10
12377258
Infect Genet Evol. 2004 Dec;4(4):345-51
15374532
Adv Parasitol. 2007;64:1-109
17499100
PLoS Pathog. 2009 May;5(5):e1000410
19412340
Infect Genet Evol. 2007 Dec;7(6):675-84
17704009
Trends Ecol Evol. 1996 Feb;11(2):41-6
21237759
Parasitology. 1989 Dec;99 Pt 3:391-402
2575239
Science. 2009 Apr 10;324(5924):265-8
19359589
Parasitol Today. 1992 May;8(5):174-7
15463609
Microbes Infect. 2007 Mar;9(3):334-43
17307010
Proc Natl Acad Sci U S A. 1990 Apr;87(7):2414-8
2320563
Heredity (Edinb). 2010 Feb;104(2):135-40
19812614
Mol Biochem Parasitol. 2007 Jan;151(1):133-6
17134768
Nature. 1986 Jul 10-16;322(6075):173-5
3724860
Annu Rev Phytopathol. 1996;34:457-77
15012552
Hereditas. 1987;107(1):95-101
3429255
J Eukaryot Microbiol. 1997 Sep-Oct;44(5):408-11
9304809
Parasit Vectors. 2009 Sep 21;2(1):43
19772562
Proc Natl Acad Sci U S A. 1993 Feb 15;90(4):1599-603
8381972
Nucleic Acids Res. 2005 Nov 27;33(21):6688-93
16314301
Parasitol Today. 1993 Feb;9(2):58
15463709
Science. 2000 May 19;288(5469):1211-5
10817991
Proc Natl Acad Sci U S A. 2000 Nov 21;97(24):13442-7
11078512
Parasitology. 2000 May;120 ( Pt 5):513-26
10840981
Parasit Vectors. 2008 Feb 25;1(1):4
18298832
Infect Genet Evol. 2007 Mar;7(2):308-32
16949350
Proc Natl Acad Sci U S A. 2009 Jun 23;106(25):10224-9
19497885
Mol Biochem Parasitol. 1992 Feb;50(2):197-204
1311052
Acta Trop. 1995 Aug;59(4):293-307
8533665
J Parasitol. 1995 Jun;81(3):395-403
7776124
Proc Natl Acad Sci U S A. 2001 Jun 5;98(12):6720-4
11381112
Am J Trop Med Hyg. 2007 Mar;76(3):573-8
17360886
Proc Natl Acad Sci U S A. 2001 Jun 19;98(13):7396-401
11416213
Nature. 2003 Feb 27;421(6926):936-9
12606999
Trends Parasitol. 2002 Feb;18(2):81-5
11832299
Mol Biochem Parasitol. 2005 Sep;143(1):12-9
15941603