U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            BONTELL, IRENE - University Of Leedsitem
                                            HALL, NEIL - University Of Liverpoolitem
                                            ASHELFORD, KEVIN - University Of Liverpoolitem
                                            Dubey, Jitenderitem
                                            BOYLE, JON - University Of Pittsburghitem
                                            LINDH, JOHAN - Swedish Institute For Infectious Disease Controlitem
                                            SMITH, JUDITY - University Of Leeds
  Submitted to: Genome Biology
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 6/5/2009
                                    Publication  Date: 8/1/2009
                                    Citation: Bontell, I.L., Hall, N., Ashelford, K.E., Dubey, J.P., Boyle, J.P., Lindh, J., Smith, J.E. 2009. Whole genome sequencing of a recombinant type II/III Toxoplasma gondii strain from Uganda reveals chromosome sorting and local allelic variants. Genome Biology 10:R53.Interpretive Summary: Toxoplasma gondii is a single-celled parasite of all warm-blooded hosts worldwide. It causes mental retardation and loss of vision in children, and abortion in livestock. Cats are the main reservoir of T. gondii because they are the only hosts that can excrete the resistant stage (oocyst) of the parasite in the feces. Humans become infected by eating undercooked meat from infected animals and food and water contaminated with oocysts. This paper reports genetic characteristics of Toxoplasma isolates from chickens from Uganda. The results will be of interest to biologists, parasitologists, and veterinarians.
                                Technical Abstract: Toxoplasma gondii is a zoonotic parasite of global importance. In common with many protozoan parasites it has the capacity for sexual recombination, but current evidence suggests this is rarely employed.  The global population structure is dominated by a small number of clonal genotypes, which exhibit biallelic variation and limited intralineage divergence.  Little is known of the genotypes present in Africa despite the importance of AIDS associated toxoplasmosis. We here present extensive sequence analysis of eight isolates from Uganda, including the whole genome sequencing of a type II/III recombinant isolate, TgCkUg2.  454 sequencing gave 84% coverage across the >61Mb genome and over 70,000 SNPs were mapped against reference strains. TgCkUg2 was shown to contain entire chromosomes of either type II or type III origin demonstrating chromosome sorting rather than intrachromosomal recombination. 1252 novel polymorphisms were mapped and clusters of new SNPs within coding sequence implied positive selection on a number of genes, including surface antigens and rhoptry proteins. Further sequencing of the remaining isolates, six type II and one type III strain, confirmed the presence of novel SNPs, suggesting these are local allelic variants within Ugandan type II strains. In mice, the type III isolate had parasite burdens at least 30-fold higher than type II isolates, while the recombinant strain had an intermediate burden. The quantity of high confidence SNP data generated in this study and the availability of the putative parental strains to this natural recombinant provide an excellent basis for future studies of the genetic divergence and of genotype phenotype relationships.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov