Genomic linkage map of the human blood fluke Schistosoma mansoni.
BACKGROUND
Schistosoma mansoni is a blood fluke that infects approximately 90 million people. The complete life cycle of this parasite can be maintained in the laboratory, making this one of the few experimentally tractable human helminth infections, and a rich literature reveals heritable variation in important biomedical traits such as virulence, host-specificity, transmission and drug resistance. However, there is a current lack of tools needed to study S. mansoni's molecular, quantitative, and population genetics. Our goal was to construct a genetic linkage map for S. mansoni, and thus provide a new resource that will help stimulate research on this neglected pathogen.


RESULTS
We genotyped grandparents, parents and 88 progeny to construct a 5.6 cM linkage map containing 243 microsatellites positioned on 203 of the largest scaffolds in the genome sequence. The map allows 70% of the estimated 300 Mb genome to be ordered on chromosomes, and highlights where scaffolds have been incorrectly assembled. The markers fall into eight main linkage groups, consistent with seven pairs of autosomes and one pair of sex chromosomes, and we were able to anchor linkage groups to chromosomes using fluorescent in situ hybridization. The genome measures 1,228.6 cM. Marker segregation reveals higher female recombination, confirms ZW inheritance patterns, and identifies recombination hotspots and regions of segregation distortion.


CONCLUSIONS
The genetic linkage map presented here is the first for S. mansoni and the first for a species in the phylum Platyhelminthes. The map provides the critical tool necessary for quantitative genetic analysis, aids genome assembly, and furnishes a framework for comparative flatworm genomics and field-based molecular epidemiological studies.
Criscione
Charles D
CD
Department of Biology, Texas A&M University, College Station, TX 77843, USA. ccriscione@mail.bio.tamu.edu
Valentim
Claudia L L
CL
Hirai
Hirohisa
H
LoVerde
Philip T
PT
Anderson
Timothy J C
TJ
D000818:Animals; D002874:Chromosome Mapping; D020090:Chromosome Segregation; D005260:Female; D008040:Genetic Linkage; D005819:Genetic Markers; D049751:Genome, Helminth / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008018:Life Cycle Stages; D008297:Male; D011995:Recombination, Genetic / Q000235:genetics; D012550:Schistosoma mansoni / Q000235:genetics* / Q000254:growth & development; D012730:Sex Chromosomes / Q000235:genetics
D005819:Genetic Markers