Leishmania donovani is the main cause of visceral leishmaniasis (VL) in East Africa. Differences between northern Ethiopia/Sudan (NE) and southern Ethiopia (SE) in ecology, vectors, and patient sensitivity to drug treatment have been described, however the relationship between differences in parasite genotype between these two foci and phenotype is unknown. Whole genomic sequencing (WGS) was carried out for 41 L . donovani strains and clones from VL and VL/HIV co-infected patients in NE (n = 28) and SE (n = 13). Chromosome aneuploidy was observed in all parasites examined with each isolate exhibiting a unique karyotype. Differences in chromosome ploidy or karyotype were not correlated with the geographic origin of the parasites. However, correlation between single nucleotide polymorphism (SNP) and geographic origin was seen for 38/41 isolates, separating the NE and SE parasites into two large groups. SNP restricted to NE and SE groups were associated with genes involved in viability and parasite resistance to drugs. Unique copy number variation (CNV) were also associated with NE and SE parasites, respectively. One striking example is the folate transporter (FT) family genes ( LdBPK _100390, LdBPK _100400 and LdBPK _100410) on chromosome 10 that are single copy in all 13 SE isolates, but either double copy or higher in 39/41 NE isolates (copy number 2–4). High copy number (= 4) was also found for one Sudanese strain examined. This was confirmed by quantitative polymerase chain reaction for LdBPK_100400 , the L . donovani FT1 transporter homolog. Good correlation (p = 0.005) between FT copy number and resistance to methotrexate (0.5 mg/ml MTX) was also observed with the haploid SE strains examined showing higher viability than the NE strains at this concentration. Our results emphasize the advantages of whole genome analysis to shed light on vital parasite processes in Leishmania . Author summary Approximately 200,000–400,000 new cases of visceral leishmaniasis (VL) occur annually resulting in an estimated 40,000 deaths. Almost 90% of the reported cases are caused by the Leishmania donovani occurring primarily in East Africa and the Indian subcontinent. Parasites in East Africa are more polymorphic than those isolated in other regions, and differences in vectors, biotopes and patient response to drugs are found in Ethiopia. Large-scale whole genome sequence (WGS) analysis of L . donovani strains and clones isolated from VL and HIV + -VL co-infected patients in Ethiopia was carried out. Single nucleotide polymorphism (SNP) and gene copy number variation (CNV) analysis shows genetic differences correlated with geographic regions in Ethiopia. These differences are associated with distinct biological processes and molecular functions, and may be associated with genes involved in drug resistance and parasite survival.
【초록키워드】 Treatment, HIV, Variation, polymorphism, drugs, drug, parasites, polymerase chain reaction, sensitivity, Region, survival, Single nucleotide polymorphism, viability, Patient, Genotype, phenotype, SNP, drug resistance, drug treatment, methotrexate, WGS, correlation, group, single nucleotide, Quantitative, CNV, genomic sequencing, nucleotide, Concentration, Analysis, strain, isolates, deaths, copy number, folate, Chain Reaction, visceral leishmaniasis, Leishmania donovani, Indian subcontinent, Ecology, Leishmaniasis, chromosome, Author, genetic differences, clones, quantitative polymerase chain reaction, clone, whole genome, Leishmania, parasite, vectors, homolog, chromosome 10, karyotype, molecular functions, single copy, foci, East, whole genome sequence, Good, regions, isolate, difference, polymerase chain, resulting, described, examined, caused, example, carried, involved, reported, occur, unique, correlated, groups, exhibiting, biological processe, genetic difference, MTX, not correlated, 【제목키워드】 survival, strain, reveal, Ethiopian,