title: The genetic map of Xiphophorus fishes represented by 24 multipoint linkage groups.
abstract: Hybrids between distinct Xiphophorus species have been utilized for over 70 years to study melanoma and other neoplasms that can develop spontaneously in hybrid offspring. Genetic linkage mapping has proven to be important in delineating genomic areas that harbor oncogenes and tumor suppressors. Within this report, two parallel backcrosses have been utilized to generate a genetic linkage map for Xiphophorus fishes. Isozyme/allozyme, RFLP and PCR-based mapping techniques, including AP-PCR/RAPDs and microsatellite loci were utilized. The derived linkage map provides a total of 403 mapped polymorphisms distributed among 24 linkage groups, representative of 24 acro- and telocentric chromosome pairs. Genomic coverage is approximately one marker per 5.8 cM. Detailed genotypic analysis of the utilized hybrids revealed two areas of the genome that show significant segregation distortion. Loci within the linkage group harboring the sex determining locus (LG 24) and an autosomal linkage group (LG 21) show highly significant deviations from Mendelian expectations. This phenomenon is not present in a hybrid cross that utilizes a different backcross hybrid progenitor species. The derived map with sequence-tagged markers provides a framework for physical map generation, large-scale genomic sequencing and will further enable cross-genome comparisons of vertebrate genomes.
authors.affiliation: Wistar Institute, Program of Molecular and Cellular Oncogenesis, Philadelphia, Pennsylvania 19104, USA. skazianis@wistar.upenn.edu
authors.forename: Steven
authors.initials: S
authors.lastname: Kazianis
authors.forename: Rodney S
authors.initials: RS
authors.lastname: Nairn
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Walter
authors.forename: Dennis A
authors.initials: DA
authors.lastname: Johnston
authors.forename: Jay
authors.initials: J
authors.lastname: Kumar
authors.forename: David
authors.initials: D
authors.lastname: Trono
authors.forename: Luis
authors.initials: L
authors.lastname: Della-Coletta
authors.forename: Irma
authors.initials: I
authors.lastname: Gimenez-Conti
authors.forename: J Douglas
authors.initials: JD
authors.lastname: Rains
authors.forename: Earlanda L
authors.initials: EL
authors.lastname: Williams
authors.forename: Brian M
authors.initials: BM
authors.lastname: Pino
authors.forename: Madonna M
authors.initials: MM
authors.lastname: Mamerow
authors.forename: Kelli J
authors.initials: KJ
authors.lastname: Kochan
authors.forename: Manfred
authors.initials: M
authors.lastname: Schartl
authors.forename: Juergen R
authors.initials: JR
authors.lastname: Vielkind
authors.forename: Jean-Nicolas
authors.initials: JN
authors.lastname: Volff
authors.forename: Bruce
authors.initials: B
authors.lastname: Woolcock
authors.forename: Donald C
authors.initials: DC
authors.lastname: Morizot