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遗传系谱图的分析

遗传系谱图的分析. 课件制作:江西省丰城中学 . 讲解:曾桂萍. 1. 2. Ⅰ Ⅱ. 5. 3. 4. 6. 10. 7. 8. 9. 示正常男女. 示色盲男女. 示白化男女. 示白化、色 盲兼患男女. 为了说明近亲结婚的危害性,某医生向学员分析讲解了下列有白化病和色盲两种遗传病的家族系谱图。设白化病的致病基因为 a ,色盲的致病基因为 b 。请回答:. Ⅲ. ( 1 )写出下列个体可能的基因型: Ⅲ 8 ; Ⅲ 10 。   ( 2 )若 Ⅲ 8 和 Ⅲ 10 结婚,生育子女 中只患白化病或色盲一种遗传病的概率

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遗传系谱图的分析

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  1. 遗传系谱图的分析 课件制作:江西省丰城中学  讲解:曾桂萍

  2. 1 2 Ⅰ Ⅱ 5 3 4 6 10 7 8 9 示正常男女 示色盲男女 示白化男女 示白化、色 盲兼患男女 为了说明近亲结婚的危害性,某医生向学员分析讲解了下列有白化病和色盲两种遗传病的家族系谱图。设白化病的致病基因为a,色盲的致病基因为b。请回答: Ⅲ (1)写出下列个体可能的基因型: Ⅲ8; Ⅲ10。   (2)若Ⅲ8和Ⅲ10结婚,生育子女 中只患白化病或色盲一种遗传病的概率 为;同时患两种遗传病的概率 为。   (3)若Ⅲ9和Ⅲ7结婚,子女中可能 患的遗传病是,发病的概率为。 aaXBXB或aaXBXb AAXbY或AaXbY

  3. 分析:(2) 白化病 aa×2/3Aa→1/2×2/3=1/3     正常为 1-1/3=2/3     色盲病 1/2XBXb×XbY→1/2×1/2=1/4     正常为 1-1/4=3/4 只患白化病 1/3×3/4=3/12 只患色盲病 1/4×2/3=2/12 两病兼患  1/3×1/4=1/12 全为正常  2/3×3/4=6/12 (3)   白化病 aa×2/3Aa→1/2×2/3=1/3        正常为 1-1/3=2/3        色盲病 1/2XBXb×XBY→1/2×1/4=1/8        正常为 1-1/8=7/8 只患白化病 1/3×7/8=7/24 只患色盲病 1/8×2/3=2/24 两病兼患  1/3×1/8=1/24 全为正常  2/3×7/8=7/12 患病概率为:7/24+2/24+1/24=5/12 或: 1-7/12=5/12

  4. 谢谢! 敬请各位指正!

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