Clark D V, Rogalski T M, Donati L M, Baillie D L
Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
Genetics. 1988 Jun;119(2):345-53. doi: 10.1093/genetics/119.2.345.
The organization of essential genes in the unc-22 region, defined by the deficiency sDf2 on linkage group IV, has been studied. Using the balancer nT1 (IV;V), which suppresses recombination over 49 map units, 294 lethal mutations on LGIV(right) and LGV(left) were recovered using EMS mutagenesis. Twenty-six of these mutations fell into the unc-22 region. Together with previously isolated lethal mutations, there is now a total of 63 lethal mutations which fall into 31 complementation groups. Mutations were positioned on the map using eight overlapping deficiencies in addition to sDf2. The lethal alleles and deficiencies in the unc-22 region were characterized with respect to their terminal phenotypes. Mapping of these lethal mutations shows that sDf2 deletes a minimum of 1.8 map units and a maximum of 2.5 map units. A minimum estimate of essential gene number for the region using a truncated Poisson calculation is 48. The data indicate a minimum estimate of approximately 3500 essential genes in the Caenorhabditis elegans genome.
研究了IV号连锁群上由缺失sDf2所定义的unc-22区域中必需基因的组织情况。利用抑制49个图谱单位以上重组的平衡染色体nT1（IV；V），通过EMS诱变在IV号连锁群（右侧）和V号连锁群（左侧）上获得了294个致死突变。其中26个突变位于unc-22区域。连同先前分离的致死突变，现在共有63个致死突变，分为31个互补群。除了sDf2之外，还利用8个重叠缺失将突变定位到图谱上。对unc-22区域的致死等位基因和缺失进行了终末表型特征分析。这些致死突变的定位表明，sDf2缺失的范围最小为1.8个图谱单位，最大为2.5个图谱单位。使用截断泊松计算对该区域必需基因数量的最小估计为48个。数据表明，秀丽隐杆线虫基因组中必需基因的最小估计约为3500个。
