Cristescu Melania E A, Colbourne John K, Radivojac Jelena, Lynch Michael
Department of Biology, Indiana University at Bloomington, Bloomington, IN 47405, USA.
Genomics. 2006 Oct;88(4):415-30. doi: 10.1016/j.ygeno.2006.03.007. Epub 2006 Apr 19.
We describe the first genetic linkage map for Daphnia pulex using 185 microsatellite markers, including 115 new markers reported in this study. Our approach was to study the segregation of polymorphisms in 129 F2 progeny of one F1 hybrid obtained by crossing two genetically divergent lineages of Daphnia isolated from two Oregon populations. The map spanned 1206 Kosambi cM and had an average intermarker distance of 7 cM. Linkage groups ranged in size from 7 to 185 cM and contained 4 to 27 markers. The map revealed 12 linkage groups corresponding to the expected number of chromosomes and covers approximately 87% of the genome. Tests for random segregation of alleles at individual loci revealed that 21% of the markers showed significant transmission ratio distortion (primarily homozygote deficiency) likely due to markers being linked to deleterious recessive alleles. This map will become the anchor for the physical map of the Daphnia genome and will serve as a starting point for mapping single and quantitative trait loci affecting ecologically important phenotypes. By mapping 342 tentative orthologous gene pairs (Daphnia/Drosophila) into the Daphnia linkage map, we facilitate future comparative projects.
我们利用185个微卫星标记描述了大型溞的首张遗传连锁图谱，其中包括本研究报告的115个新标记。我们的方法是研究通过杂交从俄勒冈州两个种群分离出的两个遗传差异较大的大型溞谱系所获得的一个F1杂种的129个F2后代中多态性的分离情况。该图谱跨度为1206个科桑比厘摩，标记间平均距离为7厘摩。连锁群大小从7厘摩到185厘摩不等，包含4到27个标记。该图谱揭示了12个连锁群，与预期的染色体数目相对应，覆盖了约87%的基因组。对各个位点等位基因随机分离的测试表明，21%的标记显示出显著的传递率畸变（主要是纯合子缺失），这可能是由于标记与有害隐性等位基因连锁所致。这张图谱将成为大型溞基因组物理图谱的基础，并将作为绘制影响生态重要表型的单基因座和数量性状基因座的起点。通过将342个暂定的直系同源基因对（大型溞/果蝇）定位到大型溞连锁图谱中，我们推动了未来的比较项目。
