無病無痛，沒有任何交通或人為意外的話，人類是否會進入不死永生狀態呢？725Please respect copyright.ＰＥＮＡＮＡDWJaSBHdkk
725Please respect copyright.ＰＥＮＡＮＡGU9CJOkXai
答案是，不會。725Please respect copyright.ＰＥＮＡＮＡ570izuIchv
725Please respect copyright.ＰＥＮＡＮＡgIXJD7yoWE
箇中的原因，就是在於染色體亦即是DNA的運作機制之上。725Please respect copyright.ＰＥＮＡＮＡnz3jU8713S
725Please respect copyright.ＰＥＮＡＮＡ2Ow79eR1By
725Please respect copyright.ＰＥＮＡＮＡWOp3sfUbsv
（圖1）正常人體細胞分裂的時候，染色體的長度會越來越短。725Please respect copyright.ＰＥＮＡＮＡAXVAV44NkR
725Please respect copyright.ＰＥＮＡＮＡ2d03GFSFwC
725Please respect copyright.ＰＥＮＡＮＡMslYqVPYmX
725Please respect copyright.ＰＥＮＡＮＡ9ayjOK9a18
（圖2）染色體的頂端區域，我們稱之為Telomere。正常細胞分裂後，Telomere的長度便會越來越短，所以導致染色體的總長度亦會有所減少。725Please respect copyright.ＰＥＮＡＮＡ9y0thn2rNs
725Please respect copyright.ＰＥＮＡＮＡaEoF6nasqA
725Please respect copyright.ＰＥＮＡＮＡaDXmPcBxlv
（圖3）而幹細胞進行分裂的時候，則會有著Telomerase的協助，導致Telomere的長度便並不會有所減少。725Please respect copyright.ＰＥＮＡＮＡ1hQJyNdrbZ
然而，當幹細胞變成正常細胞後，Telomerase的功能便會消失。725Please respect copyright.ＰＥＮＡＮＡBxmAnMnRh4
725Please respect copyright.ＰＥＮＡＮＡ2t71ws9Lsz
725Please respect copyright.ＰＥＮＡＮＡWaJte8CGkA
725Please respect copyright.ＰＥＮＡＮＡWc3x6DSZoK
（圖4）當Telomere長度削減到一定程度的時候，細胞便會自行啟動機制滅亡，又或者陷入衰老(Senescence)狀態。725Please respect copyright.ＰＥＮＡＮＡkEXIpZZHZP
725Please respect copyright.ＰＥＮＡＮＡjw822GO1Th
細胞滅亡或衰老的話，器官的功能便會衰退，最後亦會支撐不住，無法正常運作，促成死亡。725Please respect copyright.ＰＥＮＡＮＡZ5XYc4k4Bq
725Please respect copyright.ＰＥＮＡＮＡ1f0yLiNN9r
725Please respect copyright.ＰＥＮＡＮＡd1Dy9PNQHp
你可能會問，現在科技如此倡明，那麼我們只要學習幹細胞的那一套方式，動用外力重啟Telomerase功能，那不就能踏入永生嗎？725Please respect copyright.ＰＥＮＡＮＡN5ynN8Zb6m
725Please respect copyright.ＰＥＮＡＮＡlOmjvwDdMJ
這個思路並沒有錯，只不過代價就是會增加患癌的風險。725Please respect copyright.ＰＥＮＡＮＡ1jdRNbLu5u
725Please respect copyright.ＰＥＮＡＮＡKhttUiORW3
事實上，不少癌細胞的特徵就是Telomere長度非常之短，但又有著一定水平的Telomerase功能穩定維持著Telomere的長度，逃避進入滅亡的命運。725Please respect copyright.ＰＥＮＡＮＡJmN7rTIWni
725Please respect copyright.ＰＥＮＡＮＡHHqeTK4kI4
另一方面的想，如果細胞真的是踏入「永生」狀態的話，終有一天無可避免會累積各種的DNA變異，促成癌細胞的誕生。725Please respect copyright.ＰＥＮＡＮＡ1rMIIMuPwU
725Please respect copyright.ＰＥＮＡＮＡakPmEkrZ0f
（圖5）既然Telomere對細胞的壽命有著重要影響的話，那麼一些較為長壽的物種是否擁有較長的Telomere呢？725Please respect copyright.ＰＥＮＡＮＡuPJja51fqh
725Please respect copyright.ＰＥＮＡＮＡoylO29QFsy
科學家比較各物種的Telomere後（Ref1)，發現海豚的起始Telomere長度比人類高出6倍以上，但壽命長度始終是人類佔優。725Please respect copyright.ＰＥＮＡＮＡmmEaqyS6Uo
725Please respect copyright.ＰＥＮＡＮＡaIDNcPujaY
725Please respect copyright.ＰＥＮＡＮＡZ4TqMakubd
反而，決定物種壽命長度的其中一種因素，則是Telomere衰減的速度；725Please respect copyright.ＰＥＮＡＮＡkHcCGzm53N
Telomere衰減的速度只是一個參考性的指標，並非絕對。物種的大小、新陳代謝機制的不同等等均會對壽命長度有著影響。725Please respect copyright.ＰＥＮＡＮＡPZ0FQfIkf2
725Please respect copyright.ＰＥＮＡＮＡ383cXcaieH
人類每年約會減少71單位Telomere的長度，最高壽命為120歲。725Please respect copyright.ＰＥＮＡＮＡ70aK5ZGrbf
而老鼠每年會減少7000單位Telomere長度，最高壽命為5歲。725Please respect copyright.ＰＥＮＡＮＡcT7RNlQom1
725Please respect copyright.ＰＥＮＡＮＡK6WjMnzRMa
人類：每年減少71；120歲725Please respect copyright.ＰＥＮＡＮＡCi3AvDbLG8
大象：每年減少109；66歲725Please respect copyright.ＰＥＮＡＮＡ3YIPlQ4EPW
紅鸛：每年減少105；60歲725Please respect copyright.ＰＥＮＡＮＡvZ6D2FWKaO
海豚：每年減少766；52歲725Please respect copyright.ＰＥＮＡＮＡTjqRDzP07Q
兀鷲：每年減少209；41歲725Please respect copyright.ＰＥＮＡＮＡrfhaSFWcbf
海鷗：每年減少771；25歲725Please respect copyright.ＰＥＮＡＮＡzB1J3CQLWQ
馴鹿：每年減少531；22歲725Please respect copyright.ＰＥＮＡＮＡ1YVeL3KdVA
山羊：每年減少363；21歲725Please respect copyright.ＰＥＮＡＮＡXA0Y0J96lL
老鼠：每年減少7000；5歲725Please respect copyright.ＰＥＮＡＮＡVyZirtzZnM
725Please respect copyright.ＰＥＮＡＮＡaj3a3PbPsx
725Please respect copyright.ＰＥＮＡＮＡnrk45ZjAZ8
龜又是每年減少幾多呢？有待有心人發掘。725Please respect copyright.ＰＥＮＡＮＡ4u1lwxUViQ
725Please respect copyright.ＰＥＮＡＮＡB0ywES8zF4
725Please respect copyright.ＰＥＮＡＮＡDufV4hwpeh
如果想我快啲出文的話，請入去Penana網站科普專欄–薯不揀單俾一個like以及Bookmark，這對我非常之重要。725Please respect copyright.ＰＥＮＡＮＡSBd1rLxTz6
725Please respect copyright.ＰＥＮＡＮＡv8oZgZxt9g
Link: https://www.penana.com/story/66244/%E7%A7%91%E6%99%AE%E5%B0%88%E6%AC%84-%E8%96%AF%E4%B8%8D%E6%8F%80%E5%96%AE/toc725Please respect copyright.ＰＥＮＡＮＡujaKkZZZzA
725Please respect copyright.ＰＥＮＡＮＡV4TZuXQyYN
同時亦可以在Penana網站裡按「買一嚿/半嚿薯仔」，以課金的方式推動我繼續搜羅資料寫文，多謝。725Please respect copyright.ＰＥＮＡＮＡib03dUyXHT
725Please respect copyright.ＰＥＮＡＮＡlH8iRq2drA
Link:725Please respect copyright.ＰＥＮＡＮＡcwePN87R4g
https://www.penana.com/user/27349/%E8%96%AF%E4%BB%94%E8%81%9E%E8%8C%B1%E8%8E%89/portfolio725Please respect copyright.ＰＥＮＡＮＡkXjr28CRKd
725Please respect copyright.ＰＥＮＡＮＡv3VnssDdGh
725Please respect copyright.ＰＥＮＡＮＡ3BjdwyNt3M
有興趣接收科學資訊的話，歡迎follow IG: potatopigtongue。725Please respect copyright.ＰＥＮＡＮＡPVWPXkyn2s
725Please respect copyright.ＰＥＮＡＮＡdKnQUr6V4o
725Please respect copyright.ＰＥＮＡＮＡIBIxQiIhOu
Ref1:https://www.pnas.org/content/116/30/15122725Please respect copyright.ＰＥＮＡＮＡstV5WdC8xQ
Penana
search
登入arrow_drop_down
註冊arrow_drop_down
