Allelic segregation and independent assortment in T. brucei crosses: Proof that the genetic system is Mendelian and involves meiosis

MacLeod, Annette; Tweedie, Alison; McLellan, Sarah; Taylor, Sonya; Cooper, Anneli; Sweeney, Lindsay; Turner, C. Michael R.; Tait, Andy

doi:10.1016/j.molbiopara.2005.04.009

Cited by 77 publications

(65 citation statements)

References 35 publications

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“…2n+n) [35]. Mendelian segregation is well established since long in T. brucei [36] and more recently meiosis-specific proteins were expressed in the nucleus mostly before cell fusion [37]. In addition, a promastigote-like cell with haploid DNA contents has been described [38], demonstrating that this excavate protist is essentially a sexual organism.…”

Section: Discussionmentioning

confidence: 99%

First Evidence of Intraclonal Genetic Exchange in Trypanosomatids Using Two Leishmania infantum Fluorescent Transgenic Clones

et al. 2014

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BackgroundThe mode of reproduction in Leishmania spp has been argued to be essentially clonal. However, recent data (genetic analysis of populations and co-infections in sand flies) have proposed the existence of a non-obligate sexual cycle in the extracellular stage of the parasite within the sand fly vector. In this article we propose the existence of intraclonal genetic exchange in the natural vector of Leishmania infantum.Methodology/Principal findingsWe have developed transgenic L. infantum lines expressing drug resistance markers linked to green and red fluorescent reporters. We hypothesized whether those cells with identical genotype can recognize each other and mate. Both types of markers were successfully exchanged within the sand fly midgut of the natural vector Phlebotomus perniciosus when individuals from these species were fed with a mixture of parental clones. Using the yellow phenotype and drug resistance markers, we provide evidence for genetic exchange in L. infantum. The hybrid progeny appeared to be triploid based on DNA content analysis. The hybrid clone analyzed was stable throughout the complete parasite life cycle. The progress of infections by the hybrid clone in BALB/c mice caused a reduction in parasite loads in both spleen and liver, and provided weight values similar to those obtained with uninfected mice. Spleen arginase activity was also significantly reduced relative to parental strains.Conclusions/SignificanceA L. infantum hybrid lineage was obtained from intraclonal genetic exchange within the midgut of the natural vector, suggesting the ability of this parasite to recognize the same genotype and mate. The yellow hybrid progeny is stable throughout the whole parasite life cycle but with a slower virulence, which correlates well with the lower arginase activity detected both in vitro and in vivo infections.

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Section: Discussionmentioning

confidence: 99%

First Evidence of Intraclonal Genetic Exchange in Trypanosomatids Using Two Leishmania infantum Fluorescent Transgenic Clones

et al. 2014

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“…It may be expected that the vector (biting fly) would transmit different genotypes through sequential feeding, and this may be translated into mixed infections in the hosts. Absence of mixed genotypes in the host may be an indication (1) of the infectiveness of mechanical transmission and/or refractory effect of infecting genotypes on maturation of subsequent genotypes, (2) that mixed genotypes are only a result of recombination in tsetse fly as earlier proposed (Jenni et al 1986) and demonstrated (MacLeod et al 2005) and (3) that the T. evansi population structure is purely clonal. Fig.…”

Section: Discussionmentioning

confidence: 98%

Population sub-structuring among Trypanosoma evansi stocks

Njiru

Constantine

2007

Parasitol Res

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To investigate the population genetic structure of Trypanosoma evansi from domesticated animals, we have analysed 112 stocks from camels, buffaloes, cattle and horses using the tandemly repeated coding sequence (MORF2) and minisatellite markers 292 and cysteine-rich acidic integral membrane protein (CRAM). We recorded a total of six alleles at the MORF2 locus, seven at 292 and 12 at the CRAM loci. Nei's genetic distance showed reduced allelic diversity between buffaloes and cattle stocks (1.2) as compared to the diversity between camels and buffaloes (3.75) and camels and cattle stock (1.69). The mean index of association (IA=0.92) significantly deviated from zero, and the average number of multilocus genotypes (G/N ratio) was 0.21. Twenty-four multilocus genotypes were defined from the combination of alleles at the three loci. The Kenyan sub-populations showed Fst=0.28 and analysis of molecular variance showed significant divergence (22.7%) between the Laikipia, Kulal and Galana regions. The regional and host distribution of multi-locus genotypes significant population differentiation and high Nei's genetic distances suggest existence of genetic sub-structuring within T. evansi stocks while the few multi-locus genotypes and deviation of association index from zero indicate the lack of recombination. In conclusion, this study reveals that some genetic sub-structuring does occur within T. evansi, which has a clonal population structure.

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“…16 The mechanism appears to be Mendelian, with occasional aneuploid progeny. 17 Dependent on the locality under study, the population genetics of T. brucei ranges from panmixia in some undisturbed natural hosts and habitats through epidemic clonality, to true clonality. 15 Among T. cruzi populations, phylogenetic analysis revealed genetic exchange 18 and hybrids were produced experimentally in the laboratory.…”

Section: Discussionmentioning

confidence: 99%

Multiple Hybrid Genotypes of Leishmania (Viannia) in a Focus of Mucocutaneous Leishmaniasis

Nolder¹,

Roncal²,

Davies³

et al. 2007

The American Journal of Tropical Medicine and Hygiene

106

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Abstract. The principal agent of mucocutaneous leishmaniasis (MCL) is the South American protozoan parasite Leishmania (Viannia) braziliensis. This organism is generally considered to be clonal, that is, it does not to undergo genetic exchange. Nevertheless, apparent hybrids between several Leishmania species have been reported in the New World and the Old World. When we characterized isolates of Leishmania (Viannia) from a single focus of cutaneous leishmaniasis (CL) and MCL, we found a remarkable phenotypic and genotypic diversity, with 12 zymodemes and 20 microsatellite genotypes. Furthermore, 26 of the 59 isolates were L. braziliensis/L. peruviana phenotypic hybrids that displayed 7 different microsatellite genotypes. A hybrid genotype was the only organism isolated from 4 patients with MCL. Thus hybrids must be included among the potential agents of MCL. Despite the propensity for clonality, hybrids are also an important feature of Leishmania (Viannia) and may give rise to epidemiologically important emergent genotypes.

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Allelic segregation and independent assortment in T. brucei crosses: Proof that the genetic system is Mendelian and involves meiosis

Cited by 77 publications

References 35 publications

First Evidence of Intraclonal Genetic Exchange in Trypanosomatids Using Two Leishmania infantum Fluorescent Transgenic Clones

First Evidence of Intraclonal Genetic Exchange in Trypanosomatids Using Two Leishmania infantum Fluorescent Transgenic Clones

Population sub-structuring among Trypanosoma evansi stocks

Multiple Hybrid Genotypes of Leishmania (Viannia) in a Focus of Mucocutaneous Leishmaniasis

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