title: A duck RH panel and its potential for assisting NGS genome assembly.
abstract: BACKGROUND
  Owing to the low cost of the high throughput Next Generation Sequencing (NGS) technology, more and more species have been and will be sequenced. However, de novo assemblies of large eukaryotic genomes thus produced are composed of a large number of contigs and scaffolds of medium to small size, having no chromosomal assignment. Radiation hybrid (RH) mapping is a powerful tool for building whole genome maps and has been used for several animal species, to help assign sequence scaffolds to chromosomes and determining their order.
  
  
  RESULTS
  We report here a duck whole genome RH panel obtained by fusing female duck embryonic fibroblasts irradiated at a dose of 6,000 rads, with HPRT-deficient Wg3hCl2 hamster cells. The ninety best hybrids, having an average retention of 23.6% of the duck genome, were selected for the final panel. To allow the genotyping of large numbers of markers, as required for whole genome mapping, without having to cultivate the hybrid clones on a large scale, three different methods involving Whole Genome Amplification (WGA) and/or scaling down PCR volumes by using the Fluidigm BioMark(TM) Integrated Fluidic Circuits (IFC) Dynamic Array(TM) for genotyping were tested. RH maps of APL12 and APL22 were built, allowing the detection of intrachromosomal rearrangements when compared to chicken. Finally, the panel proved useful for checking the assembly of sequence scaffolds and for mapping EST located on one of the smallest microchromosomes.
  
  
  CONCLUSIONS
  The Fluidigm BioMark(TM) Integrated Fluidic Circuits (IFC) Dynamic Array(TM) genotyping by quantitative PCR provides a rapid and cost-effective method for building RH linkage groups. Although the vast majority of genotyped markers exhibited a picture coherent with their associated scaffolds, a few of them were discordant, pinpointing potential assembly errors. Comparative mapping with chicken chromosomes GGA21 and GGA11 allowed the detection of the first chromosome rearrangements on microchromosomes between duck and chicken. As in chicken, the smallest duck microchromosomes appear missing in the assembly and more EST data will be needed for mapping them. Altogether, this underlines the added value of RH mapping to improve genome assemblies.
authors.affiliation: UMR INRA/ENVT Laboratoire de Génétique Cellulaire, INRA, Castanet-Tolosan 31326, France.
authors.forename: Man
authors.initials: M
authors.lastname: Rao
authors.forename: Mireille
authors.initials: M
authors.lastname: Morisson
authors.forename: Thomas
authors.initials: T
authors.lastname: Faraut
authors.forename: Suzanne
authors.initials: S
authors.lastname: Bardes
authors.forename: Katia
authors.initials: K
authors.lastname: Fève
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Labarthe
authors.forename: Valérie
authors.initials: V
authors.lastname: Fillon
authors.forename: Yinhua
authors.initials: Y
authors.lastname: Huang
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Alain
authors.initials: A
authors.lastname: Vignal
mesh_terms: D000818:Animals; D002460:Cell Line; D002645:Chickens / Q000235:genetics; D006224:Cricetinae; D004372:Ducks / Q000235:genetics*; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D005819:Genetic Markers; D060005:Genotyping Techniques; D021101:Radiation Hybrid Mapping / Q000379:methods*; D017422:Sequence Analysis, DNA / Q000379:methods*
chemical_list: D005819:Genetic Markers