题干

果蝇的棒眼与圆眼是一对相对性状(相关基因用A,a表示),长翅与残翅是一对相对性状(相关基因用B,b表示).现有一对圆眼长輝果蝇交配得到的子代比例如表所示,没有基因突变发生.下列叙述正确的是(    )

圆眼长翅

圆眼残翅

棒眼长翅

棒眼残翅

雄蝇

15
3

15
1

15
3

15
1

雌蝇

15
5

15
2

0

0

A:圆眼为显性性状,控制眼形的基因位于常染色体上

B:子代圆眼残翅雌蝇中,纯合子占 115

C:子代长翅雌蝇中,基因型为BB的个体不能存活

D:若子代出现XXY的残翅棒眼果蝇,则与母本减数分裂MⅡ期异常有关

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答案(点此获取答案解析)

D

同类题4

       Sam Higgins was a famous photographer. He travelled all over the world, taking photos for magazines and newspapers. He had photographs of earthquakes, forest fires, floods, even wars. If something interesting happened, Sam went to photograph it. His photographs won many prizes and he earned a lot of money.
      He was a married man and his wife often asked him to take her with him, but he always refused. “I travel for work, not for pleasure,” he told her. “You won't enjoy yourself, and I won't have time to look after you. Sometimes there's not even anywhere to stay and I have to sleep outside. I often don't have a good meal or a bath for days. You won't like it”
    “Sam, I'm not a child,” his wife argued. “I can look after myself. Please, take me with you next time you go overseas.”
    Sam did not say anything but he thought about it, and when he was asked to go to Africa he said, “You can come to Africa with me if you want to. I've got to take photographs of the wildlife there. It should be interesting and not too uncomfortable. We'll be staying with a ranger(森林管理员) ”
    His wife was very excited, and at first she had a very enjoyable time.
    Then one day, Sam went off to find some lions to photograph. His wife went with him, but before long they became separated(分开). They came to a fork on the way, and she walked down one way while he walked down the other. Then Sam heard her screaming. He ran back to the fork on the way and saw her running forward him. A huge lion was chasing her. Quickly Sam took out his camera and pointed it at his wife and the lion. Then he shouted, “Slow down, woman. I can't get you both in the picture.”