Prigge Vanessa, Melchinger Albrecht E, Dhillon Baldev S, Frisch Matthias
Institute of Plant Breeding, Seed Science, and Population Genetics, University of Hohenheim, Stuttgart, Germany.
Theor Appl Genet. 2009 Jun;119(1):23-32. doi: 10.1007/s00122-009-1013-6. Epub 2009 Apr 29.
Expenses for marker assays are the major costs in marker-assisted backcrossing programs for the transfer of target genes from a donor into the genetic background of a recipient genotype. Our objectives were to (1) investigate the effect of employing sequentially increasing marker densities over backcross generations on the recurrent parent genome (RPG) recovery and the number of marker data points (MDP) required, and (2) determine optimum designs for attaining RPG thresholds of 93-98% with a minimum number of MDP. We simulated the introgression of one dominant target gene for genome models of sugar beet (Beta vulgaris L.) and maize (Zea mays L.) with varying marker distances of 5-80 cM and population sizes of 30-250 plants across BC(1) to BC(3) generations. Employing less dense maps in early backcross generations resulted in savings of over 50% in the number of required MDP compared with using a constant set of markers and was accompanied only by small reductions in the attained RPG values. The optimum designs were characterized by increasing marker densities and increasing population sizes in advanced generations for both genome models. We conclude that increasing simultaneously the marker density and the population size from early to advanced backcross generations results in gene introgression with a minimum number of required MDP.
在将目标基因从供体转移到受体基因型遗传背景的标记辅助回交计划中，标记检测费用是主要成本。我们的目标是：（1）研究在回交世代中依次增加标记密度对轮回亲本基因组（RPG）恢复率和所需标记数据点（MDP）数量的影响；（2）确定以最少的MDP达到93%-98%的RPG阈值的最优设计。我们针对甜菜（Beta vulgaris L.）和玉米（Zea mays L.）的基因组模型，模拟了一个显性目标基因的渐渗过程，在回交1代到回交3代中，标记间距为5-80 cM，群体大小为30-250株。与使用固定的一组标记相比，在早期回交世代使用密度较低的图谱可使所需MDP数量节省50%以上，且RPG值的降低幅度很小。对于这两种基因组模型，最优设计的特点都是在回交后期增加标记密度和群体大小。我们得出结论，从早期到后期回交世代同时增加标记密度和群体大小，可使基因渐渗所需的MDP数量最少。
