Miller M M, Goto R M, Taylor R L, Zoorob R, Auffray C, Briles R W, Briles W E, Bloom S E
Department of Molecular Biology, Beckman Research Institute of the City of Hope National Medical Center, Duarte, CA 91010, USA.
Proc Natl Acad Sci U S A. 1996 Apr 30;93(9):3958-62. doi: 10.1073/pnas.93.9.3958.
Rfp-Y is a second region in the genome of the chicken containing major histocompatibility complex (MHC) class I and II genes. Haplotypes of Rfp-Y assort independently from haplotypes of the B system, a region known to function as a MHC and to be located on chromosome 16 (a microchromosome) with the single nucleolar organizer region (NOR) in the chicken genome. Linkage mapping with reference populations failed to reveal the location of Rfp-Y, leaving Rfp-Y unlinked in a map containing >400 markers. A possible location of Rfp-Y became apparent in studies of chickens trisomic for chromosome 16 when it was noted that the intensity of restriction fragments associated with Rfp-Y increased with increasing copy number of chromosome 16. Further evidence that Rfp-Y might be located on chromosome 16 was obtained when individuals trisomic for chromosome 16 were found to transmit three Rfp-Y haplotypes. Finally, mapping of cosmid cluster III of the molecular map of chicken MHC genes (containing a MHC class II gene and two rRNA genes) to Rfp-Y validated the assignment of Rfp-Y to the MHC/NOR microchromosome. A genetic map can now be drawn for a portion of chicken chromosome 16 with Rfp-Y, encompassing two MHC class I and three MHC class II genes, separated from the B system by a region containing the NOR and exhibiting highly frequent recombination.
Rfp-Y是鸡基因组中包含主要组织相容性复合体（MHC）I类和II类基因的第二个区域。Rfp-Y单倍型与B系统单倍型独立分离，B系统是已知作为MHC发挥功能且位于鸡基因组16号染色体（一条微染色体）上并带有单个核仁组织区（NOR）的一个区域。利用参考群体进行的连锁图谱分析未能揭示Rfp-Y的位置，使得Rfp-Y在一个包含400多个标记的图谱中处于不连锁状态。当注意到与Rfp-Y相关的限制性片段强度随着16号染色体拷贝数增加而增强时，Rfp-Y在16号染色体三体鸡的研究中其可能位置变得明显。当发现16号染色体三体个体传递三种Rfp-Y单倍型时，获得了Rfp-Y可能位于16号染色体上的进一步证据。最后，将鸡MHC基因分子图谱的黏粒簇III（包含一个MHC II类基因和两个rRNA基因）定位到Rfp-Y上，证实了Rfp-Y定位于MHC/NOR微染色体。现在可以绘制出鸡16号染色体一部分带有Rfp-Y的遗传图谱，其中包含两个MHC I类基因和三个MHC II类基因，与B系统被一个包含NOR的区域隔开且表现出高频重组。
