Mullick A, Trasler D, Gros P
Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
Genomics. 1995 Apr 10;26(3):479-88. doi: 10.1016/0888-7543(95)80166-j.
Looptail (Lp) is a mutation that profoundly affects neurulation in mouse and is characterized by craniorachischisis, an open neural tube extending from the midbrain to the tail in embryos homozygous for the mutation. Lp maps to the distal portion of mouse chromosome 1, and as part of a positional cloning approach, we have generated a high-resolution linkage map of the Lp chromosomal region. For this, we have carried out extensive segregation analysis in a total of 706 backcross mice informative for Lp and derived from two crosses, (Lp/+ x SJL/J)F1 x SJL/J and (Lp/+ x SWR/J) F1 x SWR/J. In addition, 269 mice from a (Mus spretus x C57BL/6J)F1 x C57BL/6J interspecific backcross were also used to order marker loci and calculate intergene distances for this region. With these mice, a total of 28 DNA markers corresponding to either cloned genes or anonymous markers of the SSLP or SSCP-types were mapped within a 5-cM interval overlapping the Lp region, with the following locus order and interlocus distances (in cM): centromere--D1Mit110/Atp1 beta 1/Cd3 zeta/Cd3 eta/D1Mit145-D1Hun14/D1Mit15- D1Mit111/D1Mit112-D1Mit114-D1Mit148/D1Mit205+ ++/D1Mit36/D1Mit146/D1Mit147/D1Mit270 / D1Hun13-Fcgr2-Mpp-Apoa2/Fcer1 gamma-Lp-D1Mit149/Spna1/Fcer1 alpha-Eph1-Hlix1/D1Mit62. These studies have allowed the delineation of a maximum genetic interval for Lp of 0.5 cM, a size amenable to physical mapping techniques.
环形尾（Lp）是一种对小鼠神经胚形成有深远影响的突变，其特征为颅脊柱裂，即纯合突变胚胎中从中脑延伸至尾部的开放性神经管。Lp定位于小鼠1号染色体的远端，作为定位克隆方法的一部分，我们构建了Lp染色体区域的高分辨率连锁图谱。为此，我们对总共706只回交小鼠进行了广泛的分离分析，这些小鼠对Lp具有信息价值，来自两个杂交组合：（Lp/+×SJL/J）F1×SJL/J和（Lp/+×SWR/J）F1×SWR/J。此外，还使用了来自（小家鼠×C57BL/6J）F1×C57BL/6J种间回交的269只小鼠来排列标记位点并计算该区域的基因间距离。利用这些小鼠，共将28个与克隆基因或SSLP或SSCP类型的匿名标记相对应的DNA标记定位在与Lp区域重叠的5厘摩区间内，其位点顺序和位点间距离（以厘摩计）如下：着丝粒--D1Mit110/Atp1β1/Cd3ζ/Cd3η/D1Mit145-D1Hun14/D1Mit15-D1Mit111/D1Mit112-D1Mit114-D1Mit148/D1Mit205+++/D1Mit36/D1Mit146/D1Mit147/D1Mit270/D1Hun13-Fcgr2-Mpp-Apoa2/Fcer1γ-Lp-D1Mit149/Spna1/Fcer1α-Eph1-Hlix1/D1Mit62。这些研究确定了Lp的最大遗传区间为0.5厘摩，这一大小适合物理作图技术。
