宇勝 asked in 科學生物學 · 1 decade ago

Meiosis裏的recombination??

Meiosis裏的recombination在現代科學看來作用為何?

他跟gene flow, mutation, natural selection,還有gene drift都依樣讓我們的基因朝多樣性發展麼??

Update:

To cssnoopy:

Surely I don't. I'm an English major and studying abroad now as an exchange student in Canada. English responses are fine for me. I'm looking forward to your answer!

4 Answers

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  • C C
    Lv 6
    1 decade ago
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    do you mind an answer in english?

    2006-03-17 10:08:36 補充:

    I am a bit busy these few days that i don't really have time to write a detailed answer for you. But i will try to do that for you soon!

    2006-03-18 11:56:42 補充:

    So to explain this, let me bring up a few definitions first:gene flow = The exchange of genetic traits between populations by movement of individuals, gametes, or spores. It involves the spread of new variants among different populations through dispersal.gene drift = the change in frequency in which a gene appears in a population, through mutation, regardless of the adaptive value of the mutation.So, it is true that meiotic recombination serves the function of introducing genetic variability in the offspring.  But this variability is a combinatorial variability; the exact frequency of the gene in the population remains the same, just that they are now in different combination (i.e. haplotype) with respect to other genes.  The only true introduction of variability is "mutation", that generates new alleles.  In the eye of geneticist, mutation really isn't considered as either "GOOD" or "BAD", since a lot of times we are not talking about something that is always "BAD".  For example, variants in many genes contribute to our height, weight, etc.  It is hard to say what "height" is good, what "weight" is bad, etc.But what you need to be sure is that, natural selection and gene drift are not necessarily functioning to increase genetic variability.  Genetic drift ultimately lead to the fixation of one allele over the other allele at a particular gene, therefore it is actually "decreasing" genetic variability.  Natural selection is also working to weed out less fit alleles, or at least strive for a balance between alleles.  Therefore, natural selection and genetic drift are not the same as meiotic recombination or mutation in this sense.參考資料:usinfo.state.gov/journals/ites/0903/ijee/glossary.htmwww.carm.org/evolution/evoterms.htm

    2006-03-19 03:58:15 補充:

    Yahoo wouldn't let me enter more than 2000 characters... so here are the rest:

    2006-03-19 03:58:21 補充:

    Finally, gene flow is only introducing genetic variability if you look at a selected population. But if you broaden that population to include "globally" all of your system, it is merely the movement of set of alleles from one place to another.

    2006-03-19 03:58:38 補充:

    In conclusion, these different forces you mention are not all acting in the same direction. But they all contribute in one way or another to affect alleleic frequency and variability within the population, and what you observed is the result.

    2006-03-19 03:58:50 補充:

    Hope this helps... population genetics was awhile ago for me, but I'm starting to pick it up again. Let me know if anything's not too clear.

    2006-03-19 03:59:24 補充:

    To: 馬汀兄

    Feel free to post a question and let me know if you have posted one. I'll try to answer it if I can.

    Source(s): I am a graduate student in genetics~
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  • Anonymous
    1 decade ago

    請參考熱力學三大定律.

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  • 1 decade ago

    我也有一些相關問題呢~~....如果可以的話我也想問你..cssnoopy

    2006-03-22 00:06:38 補充:

    http://tw.knowledge.yahoo.com/question/?qid=130603...

    2006-03-22 00:07:53 補充:

    http://tw.knowledge.yahoo.com/question/?qid=130603...

    麻煩你啦~~cssnoopy

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  • 1 decade ago

    Meiosis裏的recombination在現代科學看來作用為何?

    ans:我有點看不懂你的意思.是指說為什麼會要有recombination嗎.

    如果是這樣的話.簡單來說.老爸和老媽生的小孩不會出現和老爸或老媽

    長的一樣.經由gene recombination的作用下.使親代兩基因間經由cross over

    作用.讓基因相互交換.

    另一個觀點就是天擇..使可以適應環境..(不知道天擇的話.可以去找 達爾文的 文章)

    他跟gene flow, mutation, natural selection,還有gene drift都依樣讓我們的基因朝多樣性發展麼??

    ans:是沒錯.應該說差不多的觀點.可是mutation比較偏離一點.他存在於好與不好之間.所以說.mutation的話.會比較少人用到.萬一mutation到壞的話.會死人的

    大概就這樣吧

    Source(s): 自己+上課
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