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番茄是二倍体植物(染色体2N=24).有一种三体,其6号染色体的同源染色体有三条(比正常的番茄多了一条6号染色体).三体在减数分裂联会时,形成一个二价体和一个单价体;3条同源染色体中的任意2条随意配对联会,另1条同源染色体不能配对,减数第一次分裂的后期,组成二价体的同源染色体正常分离,组成单价体的1条染色体随机地移向细胞的任何一极,而其他如5号染色体正常配对、分离(如图所示).

(1)在方框中绘出三体番茄减数第一次分裂后期图解.(只要画出5、6号染色体就可以,并用“5、6号”字样标明相应的染色体)____ 

(2)设三体番茄的基因型为AABBb,则花粉的基因型及其比例是____ .则根尖分生区连续分裂两次所得到的子细胞的基因型为____ .

(3)从变异的角度分析,三体形成的原因是____

(4)以马铃薯叶型(dd)的二倍体番茄为父本,以正常叶型(DDD)的三体番茄为母本(纯合体)进行杂交.试回答下列问题:

①假设D(或d)基因不在第6号染色体上,使F1的三体植株正常叶型与二倍体马铃薯叶型杂交,杂交子代叶型的表现型及比例为____ 

②假设D(或d)基因在第6号染色体上,使F1的三体植株正常叶型与二倍体马铃薯叶型杂交,杂交子代叶型的表现型及比例为____ 

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答案(点此获取答案解析)

,ABB\uff1aABb\uff1aAB\uff1aAb=1\uff1a2\uff1a2\uff1a1,AABBb,\u51cf\u6570\u7b2c\u4e00\u6b21\u5206\u88c2\u6709\u4e00\u5bf9\u540c\u6e90\u67d3\u8272\u4f53\u672a\u5206\u5f00\u6216\u662f\u51cf\u6570\u7b2c\u4e8c\u6b21\u5206\u88c2\u6709\u4e00\u5bf9\u59d0\u

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