title: Reciprocal translocation of small numbers of inbred individuals rescues immunogenetic diversity.
abstract: Genetic rescue can reduce inbreeding depression and increase fitness of small populations, even when the donor populations are highly inbred. In a recent experiment involving two inbred island populations of the New Zealand South Island robin, Petroica australis, reciprocal translocations improved microsatellite diversity and individual fitness. While microsatellite loci may reflect patterns of genome-wide diversity, they generally do not indicate the specific genetic regions responsible for increased fitness. We tested the effectiveness of this reciprocal translocation for rescuing diversity of two immunogenetic regions: Toll-like receptor (TLR) and major histocompatibility complex (MHC) genes. We found that the relatively small number of migrants (seven and ten per island) effectively brought the characteristic TLR gene diversity of each source population into the recipient population. However, when migrants transmitted TLR alleles that were already present at high frequency in the recipient population, it was possible for offspring of mixed heritage to have decreased gene diversity compared to recipient population diversity prior to translocation. In contrast to TLRs, we did not observe substantial changes in MHC allelic diversity following translocation, with limited evidence of a decrease in differentiation, perhaps because most MHC alleles were observed at both sites prior to the translocation. Overall, we conclude that small numbers of migrants may successfully restore the diversity of immunogenetic loci with few alleles, but that translocating larger numbers of animals would provide additional opportunity for the genetic rescue of highly polymorphic immunity regions, such as the MHC, even when the source population is inbred.
authors.affiliation: School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, RMC Gunn Building (B19), NSW 2006, Australia.|San Diego Zoo Global, PO Box 120551, San Diego, CA 92112, USA.
authors.forename: Catherine E
authors.identifier: http://orcid.org/0000-0002-8179-1822
authors.initials: CE
authors.lastname: Grueber
authors.affiliation: Department of Biology, University of Hawai'i at Hilo, 200 West Kāwili Street, Hilo, HI 96720, USA.
authors.forename: Jolene T
authors.initials: JT
authors.lastname: Sutton
authors.affiliation: School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
authors.forename: Sol
authors.initials: S
authors.lastname: Heber
authors.affiliation: School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
authors.forename: James V
authors.initials: JV
authors.lastname: Briskie
authors.affiliation: Allan Wilson Centre for Molecular Ecology and Evolution, Department of Zoology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
authors.forename: Ian G
authors.initials: IG
authors.lastname: Jamieson
authors.affiliation: Allan Wilson Centre for Molecular Ecology and Evolution, Department of Zoology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
authors.forename: Bruce C
authors.initials: BC
authors.lastname: Robertson
mesh_terms: D000483:Alleles; D000818:Animals; D014644:Genetic Variation; D005828:Genetics, Population; D007125:Immunogenetics; D007178:Inbreeding; D008285:Major Histocompatibility Complex / Q000235:genetics; D018895:Microsatellite Repeats; D009520:New Zealand; D020308:Songbirds / Q000235:genetics* / Q000276:immunology*; D051193:Toll-Like Receptors / Q000235:genetics
chemical_list: D051193:Toll-Like Receptors
keywords: conservation; genetic rescue; inbreeding; major histocompatibility complex; toll-like receptors