bio - genetics
2009-03-10 10:01 pm
organisms of the same species 是否 contain the same number of chromosome pairs?
回答 (2)
2009-03-12 1:52 am
✔ 最佳答案
"Pairs" 有此是, 有些不是。情況一: 全體一致, 例如人類, 人人廿三對, 男女皆同
情況二: XX為女, XO為男的性別決定系統, 如一些昆蟲, 草蜢、某些果蠅, 女比男多了一條X 染色體。
情況三: 非正常個體, 例如唐氏綜合症患者多出一條 21。
2009-03-10 10:37 pm
That's correct.
In 1887, Belgian biologist Edouard van Beneden (1846-1910) discovered that all organisms of the same species have the same number of chromosomes.
Different species may have different number of chromosomes.
2009-03-12 07:20:08 補充：
002 is correct that there are exceptions. Trisomy 21 is certainly the most common. But they're exceptions nevertheless and should not be considered as the "norm". Generally speaking, members of the same species do contain the same number of chromosomes, barring a few minor exception.
In 1887, Belgian biologist Edouard van Beneden (1846-1910) discovered that all organisms of the same species have the same number of chromosomes.
Different species may have different number of chromosomes.
2009-03-12 07:20:08 補充：
002 is correct that there are exceptions. Trisomy 21 is certainly the most common. But they're exceptions nevertheless and should not be considered as the "norm". Generally speaking, members of the same species do contain the same number of chromosomes, barring a few minor exception.
參考: 知少少份代表
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