title: Physical map of two tammar wallaby chromosomes: a strategy for mapping in non-model mammals.
abstract: Marsupials are especially valuable for comparative genomic studies of mammals. Two distantly related model marsupials have been sequenced: the South American opossum (Monodelphis domestica) and the tammar wallaby (Macropus eugenii), which last shared a common ancestor about 70 Mya. The six-fold opossum genome sequence has been assembled and assigned to chromosomes with the help of a cytogenetic map. A good cytogenetic map will be even more essential for assembly and anchoring of the two-fold wallaby genome. As a start to generating a physical map of gene locations on wallaby chromosomes, we focused on two chromosomes sharing homology with the human X, wallaby chromosomes X and 5. We devised an efficient strategy for mapping large conserved synteny blocks in non-model mammals, and applied this to generate dense maps of the X and 'neo-X' regions and to determine the arrangement of large conserved synteny blocks on chromosome 5. Comparisons between the wallaby and opossum chromosome maps revealed many rearrangements, highlighting the need for comparative gene mapping between South American and Australian marsupials. Frequent rearrangement of the X, along with the absence of a marsupial XIST gene, suggests that inactivation of the marsupial X chromosome does not depend on a whole-chromosome repression by a control locus.
authors.affiliation: ARC Centre of Excellence for Kangaroo Genomics, Research School of Biological Sciences, The Australian National University, Canberra, ACT 0200, Australia. Janine.Deakin@anu.edu.au
authors.forename: Janine E
authors.initials: JE
authors.lastname: Deakin
authors.forename: Edda
authors.initials: E
authors.lastname: Koina
authors.forename: Paul D
authors.initials: PD
authors.lastname: Waters
authors.forename: Ruth
authors.initials: R
authors.lastname: Doherty
authors.forename: Vidushi S
authors.initials: VS
authors.lastname: Patel
authors.forename: Margaret L
authors.initials: ML
authors.lastname: Delbridge
authors.forename: Bianca
authors.initials: B
authors.lastname: Dobson
authors.forename: James
authors.initials: J
authors.lastname: Fong
authors.forename: Yanqiu
authors.initials: Y
authors.lastname: Hu
authors.forename: Cecilia
authors.initials: C
authors.lastname: van den Hurk
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Pask
authors.forename: Geoff
authors.initials: G
authors.lastname: Shaw
authors.forename: Carly
authors.initials: C
authors.lastname: Smith
authors.forename: Katherine
authors.initials: K
authors.lastname: Thompson
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Wakefield
authors.forename: Hongshi
authors.initials: H
authors.lastname: Yu
authors.forename: Marilyn B
authors.initials: MB
authors.lastname: Renfree
authors.forename: Jennifer A Marshall
authors.initials: JA
authors.lastname: Graves
mesh_terms: D000818:Animals; D001483:Base Sequence; D033481:Chromosomes, Mammalian / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D007614:Macropodidae / Q000235:genetics*; D015335:Molecular Probes / Q000235:genetics; D008969:Molecular Sequence Data; D020161:Physical Chromosome Mapping / Q000379:methods*; D017422:Sequence Analysis, DNA; D026801:Synteny / Q000235:genetics; D014960:X Chromosome / Q000235:genetics*; D049951:X Chromosome Inactivation / Q000235:genetics*
chemical_list: D017931:DNA Primers; D015335:Molecular Probes