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Comparative Study
. 2005 Nov 27;33(21):6688-93.
doi: 10.1093/nar/gki980. Print 2005.

The genetic map and comparative analysis with the physical map of Trypanosoma brucei

Annette MacLeod  1 , Alison Tweedie, Sarah McLellan, Sonya Taylor, Neil Hall, Matthew Berriman, Najib M El-Sayed, Michelle Hope, C Michael R Turner, Andy Tait
Affiliations
Comparative Study

The genetic map and comparative analysis with the physical map of Trypanosoma brucei

Annette MacLeod et al. Nucleic Acids Res. .

Erratum in

  • Nucleic Acids Res. 2006;34(2):764

Abstract

Trypanosoma brucei is the causative agent of African sleeping sickness in humans and contributes to the debilitating disease 'Nagana' in cattle. To date we know little about the genes that determine drug resistance, host specificity, pathogenesis and virulence in these parasites. The availability of the complete genome sequence and the ability of the parasite to undergo genetic exchange have allowed genetic investigations into this parasite and here we report the first genetic map of T.brucei for the genome reference stock TREU 927, comprising of 182 markers and 11 major linkage groups, that correspond to the 11 previously identified chromosomes. The genetic map provides 90% probability of a marker being 11 cM from any given locus. Its comparison to the available physical map has revealed the average physical size of a recombination unit to be 15.6 Kb/cM. The genetic map coupled with the genome sequence and the ability to undertake crosses presents a new approach to identifying genes relevant to the disease and its prevention in this important pathogen through forward genetic analysis and positional cloning.

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Figures

Figure 1
Figure 1
Linkage maps corresponding to the 11 megabase chromosomes (I–XI) of T.brucei. All mini- and microsatellite markers (to the right in each map) have been physically assigned to chromosomes except three. Their positions on each chromosome are identified in Supplementary Tables 1–11. The genetic distance between each marker is given in centiMorgans, Haldane corrected. The genetic size of the linkage groups is given below each linkage group.
Figure 2
Figure 2
(A) The physical map of chromosome VIII of T.b. brucei (2.48 Mb) and (B) the genetic map of the same chromosome (106.2 cM). The genetic distances between markers are given in cM. Dashed lines indicate the position of all markers on the physical map. The scale bar represents 100 kb. Housekeeping genes are contained within the gene dense region, which is marked with a light grey box and gene poor regions are indicated with a dark grey box. Gene poor regions are subtelomeric regions, which mainly compose of repetitive sequences, pseudogenes and gene families.
Figure 3
Figure 3
A comparison of the physical lengths of each chromosome versus the relative sizes of the corresponding linkage groups. The line shown was determined by linear least squares regression analysis, R2 = 0.92.
Figure 4
Figure 4
Genotype segregation proportions for markers on chromosome (A) III and (B) IX. Dashed horizontal lines delimit the approximate 95% probability range for equal segregation of alleles.
See this image and copyright information in PMC

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