title: Trans-species polymorphism of the Mhc class II DRB-like gene in banded penguins (genus Spheniscus).
abstract: The Major Histocompatibility Complex (Mhc) class II DRB locus of vertebrates is highly polymorphic and some alleles may be shared between closely related species as a result of balancing selection in association with resistance to parasites. In this study, we developed a new set of PCR primers to amplify, clone, and sequence overlapping portions of the Mhc class II DRB-like gene from the 5'UTR end to intron 3, including exons 1, 2, and 3 and introns 1 and 2 in four species (20 Humboldt, six African, five Magellanic, and three Galapagos penguins) of penguin from the genus Spheniscus (Sphe). Analysis of gene sequence variation by the neighbor-joining method of 21 Sphe sequences and 20 previously published sequences from four other penguin species revealed overlapping clades within the Sphe species, but species-specific clades for the other penguin species. The overlap of the DRB-like gene sequence variants between the four Sphe species suggests that, despite their allopatric distribution, the Sphe species are closely related and that some shared DRB1 alleles may have undergone a trans-species inheritance because of balancing selection and/or recent rapid speciation. The new primers and PCR assays that we have developed for the identification of the DRB1 DNA and protein sequence variations appear to be useful for the characterization of the molecular evolution of the gene in closely related Penguin species and might be helpful for the assessment of the genetic health and the management of the conservation and captivity of these endangered species.
authors.affiliation: Department of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, Bousei-dai Isehara, Kanagawa, Japan.
authors.forename: Eri F
authors.initials: EF
authors.lastname: Kikkawa
authors.forename: Tomi T
authors.initials: TT
authors.lastname: Tsuda
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sumiyama
authors.forename: Taeko K
authors.initials: TK
authors.lastname: Naruse
authors.forename: Michio
authors.initials: M
authors.lastname: Fukuda
authors.forename: Masanori
authors.initials: M
authors.lastname: Kurita
authors.forename: Rory P
authors.initials: RP
authors.lastname: Wilson
authors.forename: Yvon
authors.initials: Y
authors.lastname: LeMaho
authors.forename: Gary D
authors.initials: GD
authors.lastname: Miller
authors.forename: Michio
authors.initials: M
authors.lastname: Tsuda
authors.forename: Koichi
authors.initials: K
authors.lastname: Murata
authors.forename: Jerzy K
authors.initials: JK
authors.lastname: Kulski
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Inoko