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在高中生物遗传的教学中,自交与自由交配作为两种重要的交配形式常出现,学生做这类题时常将两者混淆。结合多年高中教学经验,通过例题来介绍教学中如何让学生领悟其含义,掌握规律。例:基因型为Aa的玉米自交一代的种子全部种下,待其长成幼苗,人工去掉隐性个体,分成两组,一组全部自交,另一组让其自由交配。两组的植株上aa基因型的种子所占比例分别是多少?解析:Aa自交F1的基因型有三种:AA:Aa:aa=1:2:1,去掉隐
In high school biological genetics teaching, self-mating and free matings as two important forms of mating often appear, students often do such questions confuse the two. Combined with many years of high school teaching experience, through examples to introduce how to make students understand the meaning of teaching, master the law. Example: Maize inbred genotype Aa seeds of all self-planting seedlings, to be grown into seedlings, artificial removal of recessive individuals, divided into two groups, one all self-self, the other group let it mate freely. Aa: Aa: aa = 1: 2: 1, to remove the hidden difference between the two groups of plants on the proportion of aa genotypes in the seed?