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一、运用简便方法直接书写杂交后代基因型“基因的自由组合规律”是遗传的基本规律之一,它在生物学教材中占有重要位置.然而,学习这部分内容时,普遍感到难度较大,主要是在书写具有两对或多对相对性状的两亲本的杂交二代的基因型时,感到用“棋盘式”方法,既繁又慢,还容易错.但这又是一类绝对不可回避的问题.怎么办?为了解决这一问题,我本着“既然F1自花授粉,各种雄配子与各种雌配子结合的机会是相等的,那么所形成的F2的基因型的类型也应当是有规律的”这样一个设想,把运用“棋盘式”方法所得到的F的各种基因型进行了系列
First, the use of simple methods to directly write the hybrid genotypes “free combination of genes ” is one of the basic laws of inheritance, which occupies an important position in the biological textbooks.However, learning this part of the content, it is generally felt more difficult Large, mainly when writing genotypes of the second generation of parents with two or more pairs of relative traits, feel “complicated” and “tricky” In order to solve this problem, I am in “Since F1 has the chance of self-pollination, the chances of various male gametes combining with various female gametes are equal, then the gene of F2 formed The type of the type should also be regular. ”The idea is to use a series of genotypes of F obtained using the“ checkerboard ”method