Reconstructing an ancestral mammalian immune supercomplex from a marsupial major histocompatibility complex.
The first sequenced marsupial genome promises to reveal unparalleled insights into mammalian evolution. We have used the Monodelphis domestica (gray short-tailed opossum) sequence to construct the first map of a marsupial major histocompatibility complex (MHC). The MHC is the most gene-dense region of the mammalian genome and is critical to immunity and reproductive success. The marsupial MHC bridges the phylogenetic gap between the complex MHC of eutherian mammals and the minimal essential MHC of birds. Here we show that the opossum MHC is gene dense and complex, as in humans, but shares more organizational features with non-mammals. The Class I genes have amplified within the Class II region, resulting in a unique Class I/II region. We present a model of the organization of the MHC in ancestral mammals and its elaboration during mammalian evolution. The opossum genome, together with other extant genomes, reveals the existence of an ancestral "immune supercomplex" that contained genes of both types of natural killer receptors together with antigen processing genes and MHC genes.
Belov
Katherine
K
Centre for Advanced Technologies in Animal Genetics and Reproduction, Faculty of Veterinary Science, The University of Sydney, Camden, Australia. kbelov@camden.usyd.edu.au
Deakin
Janine E
JE
Papenfuss
Anthony T
AT
Baker
Michelle L
ML
Melman
Sandra D
SD
Siddle
Hannah V
HV
Gouin
Nicolas
N
Goode
David L
DL
Sargeant
Tobias J
TJ
Robinson
Mark D
MD
Wakefield
Matthew J
MJ
Mahony
Shaun
S
Cross
Joseph G R
JG
Benos
Panayiotis V
PV
Samollow
Paul B
PB
Speed
Terence P
TP
Graves
Jennifer A Marshall
JA
Miller
Robert D
RD
D000818:Animals; D002875:Chromosomes / Q000235:genetics; D019143:Evolution, Molecular; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D017403:In Situ Hybridization; D008285:Major Histocompatibility Complex / Q000235:genetics* / Q000276:immunology*; D008394:Marsupialia / Q000235:genetics* / Q000276:immunology*; D008677:Metaphase; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics
D012333:RNA, Messenger