Kuroda Noriyuki, Figueroa Felipe, O'hUigin Colm, Klein Jan
Max-Planck-Institut für Biologie, Abteilung Immungenetik, Corrensstrasse 42, 72076 Tübingen, Germany.
Immunogenetics. 2002 Sep;54(6):418-30. doi: 10.1007/s00251-002-0473-5. Epub 2002 Jul 16.
In the zebrafish, Danio rerio, and other teleosts, the class I and class II loci of the major histocompatibility complex ( Mhc) reside on different chromosomes. To shed light on the events that might have generated this difference from tetrapods, in which these two types of loci are clustered in a single chromosomal region, the organization of the class II loci in linkage group 8 of the zebrafish was determined by the characterization of contigs of PAC clones. Three contigs were defined: DAB, DCB, and DBB. The 350-kb-long DAB contig contained only four genes: DDB, DAB, SLC7A4, and DAA. The 150-kb-long DCB contig contained the DCB, DCA, and fz10 genes at an undetermined distance from the DAB contig. And the 120-kb-long DBB contig comprised the DBB gene presumably in another linkage group. The low gene density of the linkage group 8 contigs, contrasting with the high gene density of the zebrafish class I region, and the close association with genes [ SLC7A4 coding for an amino acid transporter, and fz10 (frizzled 10) coding for a receptor of the WNT glycoprotein] that are not linked with the tetrapod Mhc, is interpreted to mean that the separation of the class II from class I loci in teleosts occurred by translocation rather than by genomic or chromosomal duplication.
在斑马鱼（Danio rerio）和其他硬骨鱼中，主要组织相容性复合体（Mhc）的I类和II类基因座位于不同的染色体上。为了弄清楚可能导致与四足动物产生这种差异的事件，在四足动物中这两种类型的基因座聚集在一个单一的染色体区域，通过对PAC克隆重叠群的表征确定了斑马鱼连锁群8中II类基因座的组织形式。定义了三个重叠群：DAB、DCB和DBB。350 kb长的DAB重叠群仅包含四个基因：DDB、DAB、SLC7A4和DAA；150 kb长的DCB重叠群包含DCB、DCA和fz10基因，但与DAB重叠群之间距离未确定；120 kb长的DBB重叠群可能包含DBB基因且位于另一个连锁群中。连锁群8重叠群的基因密度较低，与斑马鱼I类区域的高基因密度形成对比；并且与四足动物Mhc不连锁的基因（编码氨基酸转运蛋白SLC7A4和WNT糖蛋白受体fz10）紧密关联，这被解释为意味着硬骨鱼中II类基因座与I类基因座分离是通过易位而非基因组或染色体复制发生 的
