標題:
精子和卵子內的Ｘ染色體相同嗎？
發問:
如果它們的Ｘ染色體都相同，豈不是只需要精子的性染色體便可以決定性別？ 更新: 我想問的是，使用２顆精子的細胞核作結合也可以嗎？ 因為精子有分Ｘ和Ｙ，只有精子也可以出現ＸＸ和ＸＹ的組合。
最佳解答:
You are right. The production of offspring from a single parent is called "parthenogenesis". See wiki here: http://en.wikipedia.org/wiki/Parthenogenesis It should be noted that only female offspring can be produced by parthenogenesis. In animal, parthenogenesis may have some problems because genomic imprinting is not probably established. Imprinting refers to the mono-allelic expression of particular genes from only one of the allele either of paternal or maternal origin. In other words, if both copies of chromosome are from sperm, imprinting is defected. Defect in imprinting will result in abnormal development or imprinting dieseas. What is more, in normal cell, one of the X chromosome in females is inactivated (X inactivation) by a non-coding RNA called Xist, while in males, the only X chromosome is active all the time.
其他解答:
002 已經ans左...不過可能ans得複雜左...我黎超簡化la 精子冇錯係有x 同y. 但精子所帶既genetic info 係好少, 你睇佢地要swim去egg架嘛, so一定要輕少. so帶既genes 會比egg少好多. 如果真係比精子xx or xy結合, 個生物一定唔要完整 (有好多 genetic上既缺憾) 而egg可能你知so冇問? 咁我就唔多講. 好明顯我唔係將002篇野黎translate, 我只係以一個easy d 理解黎explain. 如果你未到大學程度, 應該未見過呢d字眼同theory卦...(唔知now f.6-7既syllbus係咩la)|||||係呀, 你講得無錯,第23組染色體係決定該生命體係男定係女, 佢係2條為一組, 如果係xx, 即係生女, xy就係生仔, 女人唔會有y染色體, 所以無仔生唔係女人既錯, 係男人既問題
精子和卵子內的Ｘ染色體相同嗎？
發問:
如果它們的Ｘ染色體都相同，豈不是只需要精子的性染色體便可以決定性別？ 更新: 我想問的是，使用２顆精子的細胞核作結合也可以嗎？ 因為精子有分Ｘ和Ｙ，只有精子也可以出現ＸＸ和ＸＹ的組合。
最佳解答:
You are right. The production of offspring from a single parent is called "parthenogenesis". See wiki here: http://en.wikipedia.org/wiki/Parthenogenesis It should be noted that only female offspring can be produced by parthenogenesis. In animal, parthenogenesis may have some problems because genomic imprinting is not probably established. Imprinting refers to the mono-allelic expression of particular genes from only one of the allele either of paternal or maternal origin. In other words, if both copies of chromosome are from sperm, imprinting is defected. Defect in imprinting will result in abnormal development or imprinting dieseas. What is more, in normal cell, one of the X chromosome in females is inactivated (X inactivation) by a non-coding RNA called Xist, while in males, the only X chromosome is active all the time.
其他解答:
002 已經ans左...不過可能ans得複雜左...我黎超簡化la 精子冇錯係有x 同y. 但精子所帶既genetic info 係好少, 你睇佢地要swim去egg架嘛, so一定要輕少. so帶既genes 會比egg少好多. 如果真係比精子xx or xy結合, 個生物一定唔要完整 (有好多 genetic上既缺憾) 而egg可能你知so冇問? 咁我就唔多講. 好明顯我唔係將002篇野黎translate, 我只係以一個easy d 理解黎explain. 如果你未到大學程度, 應該未見過呢d字眼同theory卦...(唔知now f.6-7既syllbus係咩la)|||||係呀, 你講得無錯,第23組染色體係決定該生命體係男定係女, 佢係2條為一組, 如果係xx, 即係生女, xy就係生仔, 女人唔會有y染色體, 所以無仔生唔係女人既錯, 係男人既問題
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