Editing the Human Genome
Inson genomini tahrirlash
Sarlavha va pastdagi so‘zlarga qarang. Matn nima haqida bo‘lishi mumkin? Bir daqiqa o‘ylab ko‘ring — bu miyani o‘qishga tayyorlaydi.
CRISPR texnologiyasi, uning imkoniyatlari va axloqiy muammolari haqida.
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In 2012, a scientific paper by the biochemists Jennifer Doudna and Emmanuelle Charpentier described a technique that would transform biology within a decade. Known as CRISPR-Cas9, it allows scientists to cut DNA at a precisely chosen location and alter the genetic code with unprecedented ease. Genetic modification had been possible for decades, but earlier methods were slow, expensive and imprecise. CRISPR, by contrast, is cheap enough to be used in thousands of laboratories worldwide, and in 2020 its inventors were awarded the Nobel Prize in Chemistry.
2012-yilda biokimyogarlar Jennifer Daudna va Emmanuel Sharpantyening ilmiy maqolasi o‘n yil ichida biologiyani o‘zgartirib yuboradigan usulni tasvirlab berdi. CRISPR-Cas9 nomi bilan tanilgan bu usul olimlarga DNKni aniq tanlangan joyda kesish va genetik kodni misli ko‘rilmagan osonlik bilan o‘zgartirish imkonini beradi. Genetik modifikatsiya o‘nlab yillar davomida mumkin edi, lekin avvalgi usullar sekin, qimmat va noaniq edi. CRISPR esa, aksincha, butun dunyodagi minglab laboratoriyalarda ishlatish uchun yetarlicha arzon va 2020-yilda uning ixtirochilari kimyo bo‘yicha Nobel mukofotiga sazovor bo‘lishdi.
The technique was adapted from a natural defence system. Bacteria store fragments of the DNA of viruses that have attacked them, and use these as a kind of “most wanted” list, guiding enzymes to recognise and cut the DNA of the same viruses if they attack again. Scientists realised that by replacing the stored fragment with a sequence of their own choosing, they could direct the cutting enzyme to almost any gene in any organism.
Bu usul tabiiy himoya tizimidan moslashtirilgan. Bakteriyalar o‘ziga hujum qilgan viruslar DNKsining parchalarini saqlaydi va ulardan o‘ziga xos “eng ko‘p qidirilayotganlar” ro‘yxati sifatida foydalanadi, xuddi shu viruslar yana hujum qilsa, fermentlarni ularning DNKsini tanib, kesishga yo‘naltiradi. Olimlar saqlangan parchani o‘zlari tanlagan ketma-ketlik bilan almashtirib, kesuvchi fermentni deyarli har qanday organizmdagi deyarli har qanday genga yo‘naltirish mumkinligini anglashdi.
The medical potential is immense. Thousands of diseases are caused by mutations in a single gene, and CRISPR offers, for the first time, a realistic prospect of correcting them. The first therapy based on the technique, a treatment for sickle cell disease and a related blood disorder, was approved by regulators in the United Kingdom in 2023. In this treatment, stem cells are removed from the patient’s bone marrow, edited in the laboratory and then returned to the body, where they produce healthy blood cells. Early results have been remarkable, with many patients freed from the painful crises that had dominated their lives.
Tibbiy salohiyat ulkan. Minglab kasalliklar bitta gendagi mutatsiyalar tufayli kelib chiqadi va CRISPR birinchi marta ularni tuzatishning real istiqbolini taklif qiladi. Ushbu usulga asoslangan birinchi terapiya — o‘roqsimon hujayrali kamqonlik va unga yaqin qon kasalligini davolash usuli 2023-yilda Birlashgan Qirollikda nazoratchilar tomonidan tasdiqlandi. Bu davolashda bemorning suyak ko‘migidan o‘zak hujayralar olinadi, laboratoriyada tahrirlanadi va keyin tanaga qaytariladi, u yerda ular sog‘lom qon hujayralarini ishlab chiqaradi. Dastlabki natijalar ajoyib bo‘ldi, ko‘plab bemorlar hayotiga hukmronlik qilgan og‘riqli xurujlardan xalos bo‘ldi.
Such treatments, however, edit “somatic” cells, whose changes affect only the individual patient. Far more controversial is the editing of embryos, sperm or eggs, known as germline editing, in which changes would be inherited by all future generations. In 2018, the Chinese scientist He Jiankui shocked the world by announcing the birth of twin girls whose genomes he had edited as embryos, supposedly to make them resistant to HIV. His work was condemned almost universally as reckless and unethical; the procedure had not been shown to be safe, the medical need was questionable, and the parents may not have fully understood the risks. He was later sentenced to three years in prison.
Biroq bunday davolash usullari “somatik” hujayralarni tahrirlaydi, ulardagi o‘zgarishlar faqat bemorning o‘ziga ta’sir qiladi. Embrionlar, sperma yoki tuxum hujayralarini tahrirlash — jinsiy hujayralar chizig‘ini tahrirlash ancha bahsliroq, chunki bunda o‘zgarishlar barcha kelajak avlodlarga meros bo‘lib o‘tadi. 2018-yilda xitoylik olim Xe Szyankuy genomlarini embrion holatida, go‘yoki OIVga chidamli qilish uchun tahrirlagan egizak qizlar tug‘ilganini e’lon qilib, dunyoni larzaga soldi. Uning ishi deyarli hamma tomonidan beparvo va axloqqa zid deb qoralandi; muolajaning xavfsizligi isbotlanmagan, tibbiy zarurat shubhali edi va ota-onalar xavflarni to‘liq tushunmagan bo‘lishi mumkin. Keyinchalik u uch yil qamoq jazosiga hukm qilindi.
The objections to germline editing are both practical and philosophical. On the practical side, CRISPR can cause unintended “off-target” changes elsewhere in the genome, and the effects of altering a gene may be complex and difficult to predict, since many genes have multiple functions. On the philosophical side, critics fear a slide from preventing disease towards “enhancement”, in which wealthy parents might select their children’s height, intelligence or appearance, potentially creating new forms of inequality and changing the way society views disability.
Jinsiy hujayralarni tahrirlashga e’tirozlar ham amaliy, ham falsafiy. Amaliy tomondan, CRISPR genomning boshqa joylarida kutilmagan “nishondan tashqari” o‘zgarishlarga sabab bo‘lishi mumkin va genni o‘zgartirish oqibatlari murakkab va bashorat qilish qiyin bo‘lishi mumkin, chunki ko‘p genlar bir nechta vazifani bajaradi. Falsafiy tomondan, tanqidchilar kasallikning oldini olishdan “takomillashtirish”ga sirg‘alib o‘tishdan qo‘rqishadi, bunda boy ota-onalar farzandlarining bo‘yi, aql-zakovati yoki tashqi ko‘rinishini tanlashi mumkin, bu esa yangi tengsizlik shakllarini yaratishi va jamiyatning nogironlikka qarashini o‘zgartirishi mumkin.
Defenders of the technology respond that the line between treatment and enhancement is not always clear, and that it would be strange to forbid parents from protecting their children against devastating hereditary diseases when the technology is shown to be safe. Most scientists currently support a moratorium on clinical germline editing, but not a permanent ban, arguing that the question should be revisited as the science matures and as society has a chance to debate it.
Texnologiya himoyachilari davolash va takomillashtirish o‘rtasidagi chegara har doim ham aniq emasligini va texnologiya xavfsiz ekani isbotlanganda ota-onalarga farzandlarini dahshatli irsiy kasalliklardan himoya qilishni taqiqlash g‘alati bo‘lishini aytishadi. Hozirda ko‘pchilik olimlar jinsiy hujayralarni klinik tahrirlashga doimiy taqiqni emas, balki vaqtinchalik to‘xtatishni qo‘llab-quvvatlaydi va fan rivojlanib, jamiyat buni muhokama qilish imkoniga ega bo‘lgach, masalani qayta ko‘rib chiqish kerakligini ta’kidlashadi.
What is certain is that the decisions involved are too important to be left to scientists alone. The power to rewrite the human genome raises questions about what kind of species we wish to be, and those questions belong to everyone.
Aniq narsa shuki, bu qarorlar faqat olimlarga qoldirib bo‘lmaydigan darajada muhim. Inson genomini qayta yozish qudrati biz qanday tur bo‘lishni xohlashimiz haqida savollar tug‘diradi va bu savollar hammaga tegishli.
Tushundingizmi?
Javob topa olmasangiz, «O‘qish» bosqichiga qaytib, matnga qarang — bu ham mashq.
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Asosiy g‘oya
1 What is the article mainly about?
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2 Where did the idea for CRISPR come from?
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3 What is the key difference between somatic and germline editing?
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4 Why was He Jiankui’s work condemned?
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5 What position do most scientists currently take on germline editing?
True / False / Not Given
True — matnda aynan shunday deyilgan. False — matn aksini aytadi. Not Given — matnda bu haqda ma’lumot yo‘q.
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1 Bacteria store pieces of viral DNA.
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2 The first CRISPR therapy was approved in the UK in 2023.
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3 Critics fear gene editing could create new forms of inequality.
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4 The twins have since developed health problems.
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5 According to the article, each gene has only one function.
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6 He Jiankui claimed to have made the twins resistant to HIV.
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7 In the sickle cell treatment, cells are edited inside the patient’s body.
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8 Uzbekistan has passed a law on gene editing.
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9 CRISPR has been used to cure cancer.
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10 CRISPR is cheaper than earlier methods of genetic modification.
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11 Doudna and Charpentier received the Nobel Prize in Medicine.
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12 CRISPR can sometimes cause changes in the wrong part of the genome.
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