基因的自由组合规律是高中生物教材中的重要组成部分,课本中仅就两对相对性状的遗传现象进行了分析,并由此推导出本规律的基本原理。但是,由于学生初次学习遗传方面的知识,对此规律中任意一个杂交组合的结果,难以一目了然地推断出子代表现型和基因型的种数与比例,特别是对于三对以上相对性状的遗传现象,更难以认识。因此,教学中要进一步推敲,引导学生掌握若干计算公式,这既便于检查做题的正确性,也为填写杂交组合中亲子两代的基因型奠定基础。为了便于学生学好这部分内容,我在教学中归纳了如下几点有关计算方法: (一)个体产生配子种数=2~n(n是等位基因对数,下同). 例1,基因型是AaBbCc的生物体,有三对 The principle of free combination of genes is an important part of high school biology textbooks. Only the genetic phenomenon of two pairs of relative traits is analyzed in the textbook, and the basic principle of this law is deduced. However, as a result of the students’ first-time learning of genetic knowledge, it is difficult to deduce the number and proportion of phenotypes and genotypes of the offspring, especially the inheritance of three or more relative traits, as a result of any one of the crosses in the law Phenomenon, more difficult to recognize. Therefore, the teaching should be further scrutinized to guide students to master a number of formulas, which not only facilitate the correctness of checking questions, but also to fill in the cross combination of parent-child genotypes and laid the foundation. In order to facilitate students to learn this part of the content, I summarized in the teaching of the following calculation methods: (a) the number of individuals to produce gametes = 2 ~ n (n is the number of alleles, the same below.) Example 1, AaBbCc is a type of organism, there are three pairs