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自由组合规律是高中生物的重点和难点内容之一,试题难度大,题型多,计算复杂,但也有一定规律可循。 1,个体产生的配子种数:2~n（n代表等位基因的对数）。例如:基因型为AaBbCcDdEE的个体产生的配子种数为2~4。 2.结合方式数:雌雄配子种数的乘积。例如:AaBbCcDdEE×aaBBCcDdEe,结合方式为:2~4×2~3=2~7,即128种。 3.子代表现型种数:两亲本各对性状分别相交,产生表现型种数的乘积。例如:AaBbCcDdEE×aaBBCcDdEe,Aa×aa,子代表现型为2种;Bb×BB,子代表现型为1种;Cc×Cc,子代表现型为2种;Dd×Dd,子代表现型为2种;EE×Ee,子代表现型为1种。
The free combination law is one of the key and difficult aspects of high school biology. The questions are difficult, the questions are numerous, and the calculation is complex, but there are also certain rules to follow. 1, the number of gametes produced by the individual: 2~n (n represents the logarithm of alleles). For example, individuals with the genotype AaBbCcDdEE produce 2 to 4 gametes. 2. Number of binding methods: The product of the number of male and female gametes. For example: AaBbCcDdEE×aaBBCcDdEe, the combination method is: 2~4×2~3=2~7, ie 128 kinds. 3. Sub-present species number: Each pair of traits of the two parents cross each other to produce the product of phenotypic species. For example: AaBbCcDdEE×aaBBCcDdEe, Aa×aa, subtypes represent two types of current type; Bb×BB, subtypes represent one type; Cc×Cc, subtypes represent two types; Dd×Dd, subtypes represent patterns There are 2 types; EE×Ee, and the subtype represents 1 type.