DNA、遺伝子、ゲノムという言葉を同じ意味で使っている記事やメディアがたくさんありますが、それぞれには正確な意味があります。テレビや新聞などでも間違って使用されていることが多いため、混同されるのも無理はありません。
しかし、生物学者は明確にそれぞれの意味を使い分けています。中学生や高校生の生物学の勉強においても、「DNA」「遺伝子」「ゲノム」の違いは知っておきたいものです。また、この記事ではもう一歩踏み込んで「染色体」についても解説しています！
DNA(デオキシリボ核酸)とは何か
DNAはdeoxyribonucleic acidの略で、日本語での正式名称はデオキシリボ核酸です。
DNAは細胞の核に存在する物質名です。つまり、水素、炭素、ナトリウム、グルコース——と物質名を述べるときと同じ化学物質の名称なのです。
なので「DNA＝遺伝子」ではありません！
遺伝子はたしかにDNA（またはRNA）でできています。しかし、わたしたちの体の中にあるDNAの大部分は遺伝子ではありません。なので、この2つの言葉は正確に区別しなければなりません。
DNAはとても小さな物質なのですが、それを一列に並べてみるとヒトで約２メートル、長いものでは90メートルに及ぶものもあります。1
遺伝子は有名な「二重らせん構造」をしており、自己を複製する能力があります。DNAに複製する能力があることは、生物を生物たらしめている特徴のひとつです。
DNAの外側のリン酸とデオキシリボースの部分は同じ構造の繰り返しですが、中央の部分は異なります。この中央の部分のことを「塩基」といいますが、塩基は四種類の分子（アデニン・チミン・グアニン・シトシン）からできていて、これらの分子の並び方が独自の遺伝情報となるのです。
遺伝子とは何か
遺伝子は英語のgeneの訳語で、「遺伝する単位」という意味です。専門書では「遺伝単位」と書かれる場合もあります。
ご存じのように、ヒトをはじめとするほとんどの生物の遺伝子はDNAなのですが、一部のウイルスではRNAという名前のDNAに似た物質が遺伝子です。2
前のDNAの項目で、DNAを伸ばしてみると、とても長くなると述べましたが、DNAのすべてが遺伝子であるわけではありません。DNAには遺伝子である部分とそうでない部分があります。なので、生物の「遺伝子がDNAという物質か」というとイエスですが、DNAがすべて遺伝子かというとノーなのです。また、一部のウイルスはRNAが遺伝物質です。
生物はタンパク質からできており、遺伝子は「ここがこのタンパク質になる」という情報をもっています。
タンパク質をコードしないDNAのことは「ジャンクDNA」と呼ばれます。ジャンクDNAは「ATATATATAT」というように塩基が繰り返しをしています。なので「がらくた」だと思われて、このように命名されたのですが、近年、ジャンクDNAにも機能が備わっていることがわかってきました。
染色体とは何か
ゲノムとは何かについて語るまえに、染色体についてお話しします！
染色体についてわかっていれば、ゲノムについて理解するのが簡単になるからです。
染色体とはDNAが巻き付いてそれが束になったものです。細胞分裂が行われるときにだけ、染色体は出現します。普段はDNAはばらばらに細胞の核の中を漂っています。しかし、細胞分裂を行うときには、まとまって2つに分かれないといけないので、束になるのです。
染色体の本数は生物によって決まっています。ショウジョウバエは8本、ネズミは40本、ヒトは46本です。しかし、ヒトよりジャガイモのほうが48本と多くの染色体をもっています。複雑な生物ほど多くの染色体をもつわけではありません。
染色体を区別するために、番号が振られていて、大きいものから1番、2番…と決定されています。メスとオスに分かれている生物は、同じ大きさの染色体を2本ずつもっています。ヒトでは22番染色体まであるので、合計で44本です。そして、これとは別に、性別を決定する性染色体という特殊な染色体があり、男性ではXY、女性ではXXという組み合わせの染色体をもちます。これで合計46本になります。
ゲノムとは何か
上記で染色体について学びましたが、生物が染色体を2組ずつもつのは、母方から1組、父方から1組とそれぞれ染色体を受け継ぐので、合計で2組の染色体をもつことになるからです。
しかし、生物として1個体が形成されるには一組分の染色体があればよいので、この染色体1組分のことをゲノムといいます。または、1組分の染色体に含まれるDNAの総体をゲノムということもあります。
なので、ヒトゲノムといったら、22本の常染色体とXXまたはXYの性染色体のこと、またはその染色体がもつDNAのことを指します。
まとめ – 遺伝情報を「本」に例えてみると…
DNAは「紙」です。つまり文字が書かれている素材、または物質といえます。そして、その紙で「本」が作られています。その本はA・T・C・Gの4文字で書かれています。アルファベットは26文字、日本語はひらがな・カタカナ・漢字とかなりたくさんの文字を使っていますから、4文字は少ないですね。
そして、その「本」にはいろいろなタイトルがあります。「ライオン」というタイトルだったり、「ハエ」というタイトルだったり「サクラ」だったり「大腸菌」だったり。わたしたちは「ヒト」というタイトルの本を持っています。そして、それぞれの本に書かれている内容は、その生物の設計図です。この部分はこういう物質で作る、という情報が書かれています。
しかし、設計図は複雑なので、1巻に収めることはできません。「イヌ」という本は78巻あります。「ネコ」という本は38巻あります。「ヒト」という本は46巻です。
このたとえは、
・ 紙 = DNA
・ 文字 = 塩基(アデニン・グアニン・チミン・シトシン)
・ タイトル = 種
・ 巻 = 染色体
・ 設計図 = DNA配列
と置き換えられます。
この記事では、この転写と翻訳の過程について詳しく見ていきます！
ちなみに、同じタイトルの本が100冊あれば、その100冊にはほとんど同じことが書かれています。しかし、ところどころが少しずつ違います。なので「夏目漱石」だったり「チャールズ・ダーウィン」だったりという「サブタイトル」もあります。
あなたの遺伝子は「ヒト」という本の「あなたの名前」というサブタイトルが書かれた本です。そして、全部で46巻あるその本がすべて、あなたの60兆個の細胞それぞれに1つずつ入っているのです。なので、あなたの体には60,000,000,000,000個の本が入っており、それぞれ46巻ずつあるので、2,760,000,000,000,000冊があなたの体におさめられているのです。
コメント
ivermectin covid uptodate order ivermectin
Im grateful for the blog article.Really thank you!
I am not sure where you’re getting your information, but good topic. I needs to spend some time learning much more or understanding more. Thanks for excellent info I was looking for this info for my mission.
Hey there! Do you use Twitter? I’d like to followyou if that would be okay. I’m undoubtedly enjoyingyour blog and look forward to new updates.
Im thankful for the blog post. Keep writing.
Hi, after reading this awesome paragraph i am too happy to share my familiarity here with friends.
You can definitely see your expertise within the work you write. The arena hopes for even more passionate writers like you who are not afraid to say how they believe. All the time follow your heart.
good persuasive essay phd thesis proposal writing a funeral speech
Appreciate you sharing, great blog post.Really thank you! Will read on…
Im obliged for the article post. Fantastic.
I’ll immediately clutch your rss feed as I can’t find your email subscription hyperlink or newsletter service. Do you’ve any? Kindly let me understand in order that I could subscribe. Thanks.
Does anyone have any idea We Just Vape ecigarette store in 4109 Sportsplex Drive sells eliquid manufactured by Decoded Made In UK E-liquid? I have tried sending them an email at at seattlevaporco@outlook.com
Good blog you’ve got here.. Itís hard to find high-quality writing like yours these days. I really appreciate individuals like you! Take care!!
Enjoyed every bit of your post.Really looking forward to read more. Really Cool.
I really like and appreciate your blog post.Really looking forward to read more.
As usual, I was disappointed in your blog. Thank you for the information!
A big thank you for your post.Really thank you! Will read on…
I am so grateful for your post.Really thank you! Really Great.
Touche. Great arguments. Keep up the amazing work.My blog – Bellissi Cream
Enjoyed every bit of your post. Great.
I like the helpful information you provide in your articles. I’ll bookmark your blog and check again here regularly. I’m quite certain I will learn lots of new stuff right here! Best of luck for the next!
I need to to thank you for this very good read!! I definitely loved every bit of it. I have you book-marked to look at new things you postÖ
Hello.This post was really fascinating, especially since I was investigating for thoughts on this issue last Tuesday.
legitimate mexican pharmacy online eu pharmacy online
Hello! I just wanted to ask if you ever have any issues with hackers?My last blog (wordpress) was hacked and I ended up losing a few months of hardwork due to no backup. Do you have any solutions to prevent hackers?
Thanks for sharing your thoughts on 파워볼사이트. Regards
Very neat blog article.Really looking forward to read more. Fantastic.
Bardzo interesujący temat, dziękuję za wysłanie wiadomości tlen inhalacyjny.
Really informative blog post.Really thank you! Fantastic.
Thank you for another fantastic post. Where else may anyone get that typeof information in such an ideal method of writing? I’ve a presentation subsequent week, and I’m on the search for such information.
how long does ivermectin last ivermectin for scabies dosage
Hi there colleagues, fastidious post and pleasant arguments commented here, I am actually enjoying by these.
Pretty nice post. I just stumbled upon your blog and wished to say that I’ve really enjoyed surfing around yourblog posts. In any case I will be subscribing to your feed and I hope you write again soon!
At this time it seems like BlogEngine is the top blogging platform out there right now.(from what I’ve read) Is that what you are using on your blog?
Hello mates, its wonderful post regarding cultureand entirely explained, keep it up all the time.
apartments in lynchburg va apartments in newark nj apartments slc
Fine way of explaining, and fastidious piece of writing to take information on the topic of my presentation subject, which i am going to convey in school.
I am not sure where you’re getting your information, but great topic. I needs to spend some time learning more or understanding more. Thanks for fantastic info I was looking for this info for my mission.
It¡¦s really a cool and useful piece of information. I¡¦m satisfied that you shared this useful info with us. Please keep us informed like this. Thanks for sharing.
I really like and appreciate your blog.Really thank you! Will read on…
Hi. Awesome! I’m really appreciate it. It will be great if you’ll read my first article!)
I’m really impressed with your writing skills and also with the layout on your blog. Is this a paid theme or did you customize it yourself? Either way keep up the nice quality writing, it is rare to see a nice blog like this one nowadays.
Hi. Such a nice post! I’m really enjoy this. It will be great if you’ll read my first article on AP!)
Hello, yeah this paragraph is truly excellent and I’ve acquired lot of items from it regarding blogging. thanks.
I value the article.Really thank you! Want more.
I am so grateful for your article post. Much obliged.
ivermectin for humans ivermectin for sale – ivermectin 50
A company car amoxicillin 250 tablet uses The P1 was there a while back, and was rumored to have completed a lap at 7:04, which wouldâve been a production car record, but that was never confirmed, and perhaps thatâs a good thing for McLaren.
This is a very good tip especially to those fresh to the blogosphere. Short but very accurate information… Many thanks for sharing this one. A must read post!
I needed to thank you for this wonderful read!!I absolutely enjoyed every bit of it. I’ve got you book-marked to look at new stuffyou post…
Thanks for ones marvelous posting! I genuinely enjoyed reading it, you’re a great author. I will be sure to bookmark your blog and will often come back from now on. I want to encourage one to continue your great job, have a nice evening!
Good day! This is my first visit to your blog! We are a group of volunteers and starting a new project in a communityin the same niche. Your blog provided us useful information towork on. You have done a marvellous job!
Aw, this was an exceptionally good post. Taking the time and actual effort to produce a great articleÖ but what can I sayÖ I hesitate a lot and never seem to get anything done.
Ikixms – furosemidelasixx.com Jeqjcs kijjqe
provigil over the counter modalert – modalert 200
how long does it take for norvasc to work what is amlodipine for
Great, thanks for sharing this blog post. Great.
Really nice layout and fantastic content material , practically nothing else we want : D.
Hi there! I just wanted to ask if you ever have any issues with hackers? My last blog (wordpress) was hacked and I ended up losing months of hard work due to no backup. Do you have any methods to prevent hackers?
Thank you for sharing your thoughts. I truly appreciate your efforts and I will be waiting for your further post thank you once again.
What’s Happening i’m new to this, I stumbled upon thisI haave discovered It positively useful and it has aided me out loads.I’m hoping to give a contribution & help other userslike its helped me. Great job.
Bağlama Büyüsü 19 Nov, 2021 at 4:54 am Wow! This blog looks exactly like my old one!….
Hello there, just became alert to your blog through Google, and found that it is really informative.I’m going to watch out for brussels. I’ll be grateful if you continue this in future.A lot of people will be benefited from yourwriting. Cheers!
An intriguing discussion is worth comment. I believe that you need to publish more on this subject matter, it might not be a taboo subject but usually folks don’t talk about such issues. To the next! Best wishes!!
pharmacy online onlinepharmacy online pharmacy supremesuppliers.ru
A motivating discussion is worth comment. There’s no doubt that that you need to publish more about this topic, it might not be a taboo matter but typically folks don’t speak about these issues. To the next! Many thanks!!
Hi there just wanted to give you a brief heads upand let you know a few of the pictures aren’t loading correctly.I’m not sure why but I think its a linking issue. I’ve tried it in two different browsers and both show the sameresults.
Thank you for your article post. Cool.Loading…
Nice post. I used to be checking constantly this blog and I’m inspired! Extremely helpful info specifically the remaining phase 🙂 I take care of such information much. I was looking for this certain info for a long time. Thanks and good luck.
Truly no matter if someone doesn’t know after that its up to other users that they willassist, so here it takes place.
worming rabbits with ivermectin worming rabbits with ivermectin
Appreciate you sharing, great blog post. Great.
wow, awesome blog.Much thanks again. Much obliged.
I loved your blog. Want more.
Awesome blog post.Thanks Again. Much obliged.
Hey, thanks for the article.Really looking forward to read more. Really Great.
Major thankies for the post.Really thank you! Much obliged.
You bear a very special inventiveness. Your penning capabilities are without a doubt amazing. Many thanks for submitting material on-line and training your readers.
choloquine what is hydroxychloroquine chloroquine cvs
I love the efforts you have put in this, regards for all the great articles.
Greetings! Very useful advice within this post! It is the little changes which will make the most significant changes. Thanks a lot for sharing!
Howdy! Do you know if they make any pluginsto safeguard against hackers? I’m kinda paranoid about losing everythingI’ve worked hard on. Any tips?
Aw, this was an exceptionally good post. Finding the time and actual effort to produce a top notch article… but what can I say… I put things off a lot and never manage to get nearly anything done.
Hi, I do believe this is an excellent blog. I stumbledupon it 😉 I’m going to come back once again since I saved as a favorite it. Money and freedom is the best way to change, may you be rich and continue to guide others.
Im obliged for the article. Much obliged.
Well we haven’t really thought Plus accounts via subscription
Lxjueu – college essays 2016 2017 Nnfqmt areqgv
Thanks again for the article post.Thanks Again.
I do not even understand how I finished up right here,but I thought this post was good. I don’t recognize who you might be however definitelyyou are going to a well-known blogger when you are not already.Cheers!
A round of applause for your blog article.Thanks Again. Much obliged.
That is a good tip particularly to those fresh to the blogosphere. Short but very precise infoÖ Thank you for sharing this one. A must read post!
Im obliged for the blog.Thanks Again. Much obliged.
I appreciate you sharing this blog post. Want more.
This is one awesome article.Much thanks again. Cool.
Wow, great article post. Awesome.
Great blog post.Really looking forward to read more. Really Cool.
Hello, yes this piece of writing is in fact nice and I have learned lot of things from it regardingblogging. thanks.
I blog often and I truly thank you for your content.Your article has truly peaked my interest. I am going to take a note of your blog and keep checking fornew information about once per week. I opted in for your Feed too.
how to make an outline for an essaynational junior honor society essayessay topics for highschool
Thanks a lot for the blog post.Really looking forward to read more. Want more.
Hi mates, its wonderful piece of writing regarding educationand fully explained,keep it up all the time.
Very good article.Really looking forward to read more. Keep writing.
F*ckin¦ remarkable issues here. I¦m very happy to see your post. Thanks so much and i’m having a look forward to touch you. Will you please drop me a e-mail?
Thanks for sharing, this is a fantastic article post.
Wow that was strange. I just wrote an incredibly long comment but after I clicked submit my comment didn’tshow up. Grrrr… well I’m not writing all that over again. Anyways, just wanted to say excellentblog!
I’m still learning from you, while I’m trying to reach my goals. I definitely love reading everything that is written on your blog.Keep the stories coming. I enjoyed it!
Amazing! Its really awesome post, I have got much clear idea concerning from this post.
I’m really impressed with your writing skills and also with the layout on your blog. Is this a paid theme or did you customize it yourself? Anyway keep up the excellent quality writing, it is rare to see a nice blog like this one nowadays..
sulfameth/ Trimethoprim 800/160 tabs Can I drink alcohol while taking sulfamethoxazole / trimethoprim DS tablets?
I will immediately grasp your rss as I can’t to find your email subscription link or newsletter service. Do you have any? Kindly permit me recognise so that I may subscribe. Thanks.
I read this post completely regarding the comparison of most recent and preceding technologies, it’s awesome article.
F*ckin’ awesome things here. I’m very satisfied to see your post. Thanks so much and i am looking ahead to touch you. Will you please drop me a mail?
Asking questions are in fact fastidious thing if you are not understanding anything completely, but this post gives good understanding even.
ordering medicine from india: order medications online from india overseas pharmacies shipping to usa
lisinopril a beta blocker lisinopril action
600 sq ft apartment journal square apartments aspect apartments
Regards for helping out, wonderful information. “In case of dissension, never dare to judge till you’ve heard the other side.” by Euripides.
Wow that was strange. I just wrote an very long comment but after I clicked submit my comment didn’t show up. Grrrr… well I’m not writing all that over again. Anyways, just wanted to say great blog!
Excellent article. I am going through a few of these issuesas well..
Major thanks for the blog article.Much thanks again. Much obliged.
Muchos Gracias for your blog.Much thanks again. Great.
Very informative blog article.Really thank you! Fantastic.
This is one awesome blog article.Thanks Again. Fantastic.
Hi there! This post could not be written any better!Reading through this post reminds me of my previous room mate!He always kept chatting about this. I will forward this article to him.Fairly certain he will have a good read. Many thanks forsharing!
I truly appreciate this blog. Keep writing.
ivermectin for.covid ivermectin pour on for chickens
instagram takipçi sat?n alma paneliLoading…
plaquenil itching plaquenil generic vs name brand where can i get the least expensive plaquenil
Great blog post. Really Great.
Major thankies for the blog article. Fantastic.
Im obliged for the article.Thanks Again. Fantastic.
Really appreciate you sharing this blog.Really looking forward to read more. Cool.
It is really a nice and helpful piece of information. I’m glad that you simply shared this useful info with us. Please stay us informed like this. Thanks for sharing.
Muchos Gracias for your post.Thanks Again. Great.
I really liked your article.Thanks Again. Keep writing.
Whoa quite a lot of useful facts!help me with my essayresume writing service
I think this is a real great blog.Thanks Again. Really Cool.
Great, thanks for sharing this blog.
No matter if some one searches for his necessary thing, so he/she needs to be available that in detail, therefore that thing is maintained over here.
Thank you ever so for you blog post.Much thanks again.
Appreciate you sharing, great post. Fantastic.
Fantastic post.Thanks Again. Awesome.
I am so grateful for your blog.Thanks Again. Really Cool.
This is such a great resource that you are providing and you give it away for free.
Thanks for sharing, this is a fantastic article.Really looking forward to read more. Want more.
Wow, great blog post.