Ellegren H, Chowdhary B P, Fredholm M, Høyheim B, Johansson M, Bräuner Nielsen P B, Thomsen P D, Andersson L
Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala.
Genomics. 1994 Nov 15;24(2):342-50. doi: 10.1006/geno.1994.1625.
A linkage map of pig chromosome 1 (SSC1) has been constructed using 15 polymorphic markers. Eleven markers constitute PCR-based microsatellites (three associated with coding sequences), six markers have also been mapped by in situ hybridization, and homologues to four of the markers have been mapped in human. The physical assignments show that almost the entire SSC1 is covered by the linkage map, which measures 164 cM (sex-averaged). In a large region on the q arm, representing about 40% of the chromosome, there is a significant excess of male recombination. In contrast, there is a significantly higher recombination rate in females in both terminal regions. In the penultimate marker intervals on the q arm as well as the p arm, females show a fivefold excess of recombination compared to males. The rate of genetic recombination in relation to the physical DNA content is 1 cM per 2-4 Mb over at least 80% of the chromosome. In the terminal part of the q arm, however, there is a tremendous increase in the recombination rate, with 1 cM equaling about 0.4 Mb. Two homologous chromosome segments in human could be detected, ESR-CGA on human chromosome 6 (HSA6) and IFNA-RLN-GRP78 on human chromosome 9 (HSA9). Since the porcine blood group locus EAA is located close to (or possibly within) the latter conserved segment and the suggested human counterpart, the ABO system, is similarly close to the segment on HSA9, our data provide indirect evidence that these blood group systems are homologous.
利用15个多态性标记构建了猪1号染色体（SSC1）的连锁图谱。其中11个标记构成基于PCR的微卫星（3个与编码序列相关），6个标记也通过原位杂交进行了定位，并且其中4个标记的同源物已在人类中定位。物理定位表明，连锁图谱几乎覆盖了整个SSC1，其长度为164厘摩（两性平均）。在q臂上的一个大区域，约占染色体的40%，雄性重组明显过多。相比之下，两个末端区域雌性的重组率明显更高。在q臂以及p臂的倒数第二个标记区间，雌性的重组率比雄性高出五倍。在至少80%的染色体上，遗传重组率与物理DNA含量的关系是每2 - 4兆碱基1厘摩。然而，在q臂的末端部分，重组率大幅增加，1厘摩约等于0.4兆碱基。在人类中可检测到两个同源染色体片段，分别是人类6号染色体（HSA6）上的ESR - CGA和人类9号染色体（HSA9）上的IFNA - RLN - GRP78。由于猪血型位点EAA位于后一个保守片段附近（或可能在其内部），且推测的人类对应物ABO系统同样靠近HSA9上的该片段，我们的数据提供了间接证据表明这些血型系统是同源的。
