题目

已知某物种一条染色体上依次排列着A、B、C、D、E五个基因，下面列出的若干种变化中未发生染色体结构变化的是(如下图)( )A. B. C. D. 答案：【答案】D【解析】染色体结构的变异：指细胞内一个或几个染色体发生片段的缺失、增添、倒位或易位等改变，使得染色体上基因的数目和排列顺序发生改变。A、一条染色体上依次排列着A、B、C、D、E五个基因，则A种缺失D、E片段，A错误；B、一条染色体上依次排列着A、B、C、D、E五个基因，则B中多了FDear Susan,I'm very gladly to hear you are coming to visit me the next Friday. Unfortunately, I won't be able to meet you at the airport although I have classes in the afternoon. You won't find difficult to get to the city center. The airport bus leaves every 30 minute and will take you rightly to the Friendship Hotel. My classes will be over by then or I will pick you up there. I will take you together to a hot pot restaurant for dinner and we'll talk with our plan for the weekend over dinner. Having a pleasant trip and see you Friday.Yours,Zhang Ming