Part 4

Return of the king In August 1485, King Richard III of England was killed at the Battle of Bosworth and buried in Grey Friars Church near Leicester. The church was later demolished and the area eventually became a parking lot. In 2012, archeologists dug up a skeleton in the parking lot, which they suspected might belong to the missing king. Examining the evidence As with any missing person's case, the investigators brought together lots of strands of evidence to come to a conclusion. It was calculated that there was a 99.999 percent chance that the skeleton was that of Richard III. He was later reburied in Leicester Cathedral. CONSPIRACY! Many people believe that Richard III killed his two nephews in the Tower of London so that he could become king instead of his older brother's sons. The skeleton has a curved spine, as Richard was described as having. WHAT WE NOW KNOW ABOUT RICHARD III FROM HIS DNA » There's a 96 percent probability that Richard had blue eyes. » There's a 77 percent chance that he had blond hair (which darkened in adulthood). » The most accurate portrait of Richard is the one we've shown on the opposite page, from the Society of Antiquaries in London. Mitochondrial DNA Mitochondrial DNA is special because it only gets passed on through your mother. Therefore, it is identical between siblings. Richard's mitochondrial DNA was passed on by his sister to her daughters and granddaughters through the female line—for 19 generations! The skeleton showed signs of injuries suffered on the battlefield where Richard died. Geneticists compared the mitochondrial DNA sequences and found that they were identical, proving that the skeleton was that of Richard III. Mitochondrial DNA was found in the skeleton after more than 500 years! Mike and Wendy By tracing the family tree, researchers found two living relatives, Mike and Wendy. They had the same mitochondrial DNA sequence as King Richard's skeleton.

国王归来 1485年8月，英格兰国王理查三世战死在博斯沃思战役，被安葬在莱斯特附近的格雷弗莱尔斯教堂。 这座教堂后来被拆除，这片区域最终改成了停车场。 2012年，考古学家在停车场挖出一具骨架，他们怀疑这可能就是那位失踪国王的遗骸。 检验证据 和所有失踪者案件一样，调查人员整合了多条线索才得出结论。 经计算，这具骨架是理查三世的概率高达99.999%。 后来，他被重新安葬在了莱斯特大教堂。 阴谋！ 很多人认为，理查三世为了自己当上国王，杀死了被关在伦敦塔的两个侄子——也就是他哥哥的两个儿子。 这具骨架脊柱弯曲，和历史对理查三世的描述一致。 我们通过DNA对理查三世的新发现 » 理查三世有96%的概率是蓝眼睛。 » 他有77%的概率天生金发，成年后发色会变深。 » 最准确的理查三世肖像就在对页，来自伦敦文物学会。 线粒体DNA 线粒体DNA很特别，它只通过母亲传递。 因此，兄弟姐妹的线粒体DNA完全相同。 理查的线粒体DNA经由他的姐妹，通过母系一脉传递了整整19代，传到后代的女儿、孙女身上！ 骨架上留有理查战死的战场留下的伤痕痕迹。 遗传学家比对线粒体DNA序列，发现二者完全一致，证明这具骨架确实是理查三世的。 五百多年后，人们依旧从骨架中检测到了线粒体DNA！ 麦克和温蒂 研究人员追踪家族谱系，找到了两位在世亲属麦克和温蒂。 他们和理查三世骨架的线粒体DNA序列完全一致。

Can we fix genes? A genetic disorder can be caused by a mutation in just one gene. If we can fix this mutation in the cells that use the gene, then we can cure the disease. This is called gene therapy. Gene therapy There are two possible types of gene therapy. Somatic gene therapy only treats the patient's diseased cells, but germ line gene therapy changes all the cells in the body, including the ones that will be passed on to the next generation. 1 Faulty cells whose DNA needs to be edited are taken from the patient. 2 In the lab, a virus is altered genetically so that it can't make you sick. 3 The healthy version of the gene that has gone wrong in the patient's cells is inserted into the altered virus. 4 The altered virus containing the healthy DNA "infects" the cells that were removed from the patient. 5 The cells start to use the gene from the virus to make a healthy protein. 6 The altered cells are put back into the patient, and the healthy protein helps cure the disease. Changing DNA in your eggs or sperm means that the change will be passed on forever! BABY IN A BUBBLE Gene therapy can cure babies born with a weak immune system. These children can't fight off infections, so they must be kept inside germ-free "bubbles." Now, their cells can be genetically altered to give them an immune system that works, so they can live normally.

我们能修复基因吗？ 单基因突变就可能引发遗传性疾病。 如果我们能在需要用到该基因的细胞中修复这个突变，就能治愈这种疾病。 这就是基因治疗。 基因治疗 基因治疗分为两种类型。 体细胞基因治疗只治疗患者的病变细胞，而生殖系基因治疗会改变全身所有细胞，包括会传给下一代的生殖细胞。 1 先从患者体内取出需要编辑DNA的出错细胞。 2 在实验室中，我们会改造病毒的基因，让它不会让人生病。 3 把患者出错基因的健康版本插入改造后的病毒中。 4 携带健康DNA的改造病毒会“感染”从患者体内取出的这些细胞。 5 这些细胞会开始利用病毒带来的基因，合成健康的蛋白质。 6 改造后的细胞会被送回患者体内，健康的蛋白质就能帮助治愈疾病。 改变卵子或精子的DNA意味着这个改变会一直遗传下去！ 泡泡里的宝宝 基因治疗可以治愈天生免疫系统薄弱的宝宝。 这些孩子没办法抵抗感染，所以必须待在无菌的“泡泡”里。 现在，我们可以改造他们的细胞，让他们拥有能正常工作的免疫系统，这样他们就能像普通人一样生活了。

Should we change genes? Who gets access to this technology? Is it only going to be for very rich people? Intelligence could be improved? If everyone were as intelligent as Albert Einstein, what would life be like? Human disease could be cured? You might pass this on to your children. People could be more "beautiful"? If everyone were changed to be the same, a new disease might evolve that could wipe us all out! People could be more athletic? What do you think? Now that we are finding new ways of altering our genes and those of other organisms, we don't need to wait for natural selection anymore. This means that we can think about making changes for ourselves. But, is it always a good idea to tinker with genes? Disease- resistant crops? Would it taste as nice? Crops could be altered to make more food from the same number of plants? Would we end up growing fewer varieties of fruits and vegetables? Bacteria could eat plastic? Will the change spread into wild populations of the altered species? Plants could cope with drought? Will it interfere with other plants and animals that live in the same place? Fruits and vegetables could last longer in stores?

我们应该修改基因吗？ 谁能使用这项技术？ 难道只有非常有钱的人才能用吗？ 可以提升智力吗？ 如果每个人都和阿尔伯特·爱因斯坦一样聪明，生活会是什么样呢？ 人类的所有疾病都能被治愈吗？ 这个改变还可能会传给你的孩子。 我们能改造出更“漂亮”的人吗？ 如果所有人都被改成一样，可能会演化出一种新疾病，把我们全消灭掉！ 我们能改造出更擅长运动的人吗？ 你怎么看呢？ 如今我们已经找到了改造人类和其他生物基因的新方法，不用再等待自然选择了。 这意味着我们可以自己决定要做出什么样的改变。 但随意改造基因，一定是件好事吗？ 培育抗病作物？ 改造后的作物还会好吃吗？ 我们可以改造作物，让相同数量的植株产出更多粮食？ 最后我们会不会只种植很少几个品种的蔬果呢？ 改造出能吃塑料的细菌？ 这种改变会扩散到野生物种群里吗？ 改造出能适应干旱的植物？ 它会影响同区域生活的其他动植物吗？ 改造后果蔬能在商店存放更久？

Let's clone plants! Plants are special because every single cell can grow into a new plant that is a clone of the first plant. You can try cloning lavender yourself! We're indentical! 1 Take a cutting Cut a fresh, green stem with no flowers from a healthy lavender plant. Remove the leaves at the bottom of the stem so that they don't rot in the soil. 2 Plant the cutting Fill a small plant pot with free-draining compost or soil and plant the lavender cutting firmly in the middle. 3 Keep moist Water the plant well and secure a clear plastic bag over the top of the pot to keep the soil moist. Place it somewhere warm and light. Rise of the clones! Cloning is the process of producing genetically identical individuals, with exactly the same DNA. Sometimes this happens naturally, as with identical twins. Farmers clone fruit trees to make sure they produce the same tasty fruit, such as apples. Flowers Flowers make seeds when they are fertilized by other plants. Plants grown from seeds will not be clones. CLONING THEMSELVES A few, very unusual, animals can reproduce by cloning themselves. These female aphids are able to have babies without a male. They produce daughters that are all genetically identical to the mother. Cloning animals In 1996, Dolly the sheep was born. Scientists made her by transferring the DNA-containing nucleus of an udder cell into an egg without a nucleus. Dolly was a clone of the mother who gave the nucleus. A whole new sheep was made from an udder cell! 4 Enjoy the flowers After a few weeks, you will see new leaves at the top of your new plant, and eventually flowers. You have created a clone of your original plant! Egg cell The egg cell has had its nucleus destroyed to remove its own DNA. Needle A tiny needle injects the udder cell nucleus into the egg cell.

我们来克隆植物吧！ 植物很特别，因为每个植物细胞都能长成新植株，也就是原植株的克隆体。 你可以自己动手克隆薰衣草哦！ 我们长得一模一样！ 1 剪取插穗 从一株健康的薰衣草上，剪下一段不带花的新鲜绿枝条。 摘掉枝条底部的叶子，避免它们在土里腐烂。 2 种下插穗 给小花盆装上透气排水的堆肥或土壤，把薰衣草插穗稳稳种在花盆中间。 3 保持湿润 给插穗浇透水，在花盆口套上透明塑料袋，让土壤保持湿润。 把它放在温暖有光照的地方。 克隆是什么？ 克隆是培育基因完全相同个体的过程，新个体和原个体的DNA完全一致。 有时候克隆会自然发生，同卵双胞胎就是例子。 果农会克隆果树，保证结出的果实都一样香甜，苹果就是这样。 花朵 花朵被其他植株授粉后，就会结出种子。 用种子种出来的植物不是克隆体。 自我克隆 有一小部分非常特殊的动物，可以通过克隆繁殖后代。 这些雌性蚜虫不需要雄性就能生下宝宝。 它们生出的雌宝宝，基因全都和母亲完全一样。 动物克隆 1996年，克隆羊多莉出生了。 科学家把含有DNA的乳腺细胞核，移植到去掉细胞核的卵细胞中，培育出了多莉。 多莉就是提供细胞核的母羊的克隆体。 居然用一个乳腺细胞培育出了一整只全新的绵羊！ 4 欣赏花朵 几周之后，你就能看到新植株顶端长出新叶，最终还会开出花朵。 你已经成功造出原植株的克隆体啦！ 卵细胞 这个卵细胞原本的细胞核已经被破坏，移除了它自身的DNA。 注射针 一根细针会把乳腺细胞的细胞核注入卵细胞中。

How would this work? To re-create a woolly mammoth, genes from preserved remains of mammoths would be put into the DNA of the Asian elephant—the mammoth's closest living relative. The mammoth genes would give the baby traits such as shaggy hair. This would make an "elemoth"—an elephant-mammoth hybrid. Gene splicing The mammoth genes would be inserted, or spliced, into the chromosomes of an Asian elephant. Asian elephant The new DNA would be put into an elephant egg and the elemoth baby would grow in a surrogate Asian elephant mother. Return of the mammoths? Since 2015, scientists at Harvard University have been looking into bringing the woolly mammoth back from extinction. They hope to achieve this by using new technology to replace elephant genes with woolly mammoth genes. In 2012, an important woolly mammoth specimen was discovered in Russia—by an 11-year-old child! Mammoth remains Scientists are currently extracting DNA from woolly mammoth remains. They would then need to identify different genes and match them up with the elephant genes. LOST FOREVER? These are some other animal species that have become extinct, but that scientists could potentially bring back to life. Do you think this would be a good idea? Dinosaurs Dinosaurs are the ancestors of birds, so we could look at bird DNA to try and figure out how to re-create a dinosaur. Dodo The dodo became extinct hundreds of years ago. Some of its DNA has been discovered in remains.

这要怎么实现呢？ 要复活猛犸象，需要把从猛犸遗骸中保存下来的基因，植入猛犸现存最近的亲属——亚洲象的DNA中。 猛犸基因会让幼崽拥有猛犸的特征，比如浓密蓬松的长毛。 培育出的新个体叫做“象猛”，是大象和猛犸的杂交后代。 基因剪接 把猛犸基因插入，也就是剪接到亚洲象的染色体中。 亚洲象 新的DNA会被放进大象的卵细胞，“象猛”宝宝会在代孕的亚洲象妈妈体内长大。 猛犸象能重返地球吗？ 从2015年开始，哈佛大学的科学家就在研究如何让灭绝的猛犸象复活。 他们希望借助新技术，用猛犸象基因替换亚洲象的基因来实现这个目标。 2012年，俄罗斯发现了一具非常重要的猛犸象标本——发现者是一个11岁的小朋友哦！ 猛犸遗骸 目前科学家正在从猛犸遗骸中提取DNA。 之后他们还需要识别不同的基因，再和大象的基因一一对应。 永远消失了吗？ 还有一些已经灭绝的动物，科学家理论上也有可能让它们复活。 你觉得这样做好吗？ 恐龙 恐龙是鸟类的祖先，所以我们可以研究鸟类的DNA，尝试摸索复活恐龙的方法。 渡渡鸟 渡渡鸟在几百年前就灭绝了。 人们已经在它的遗骸中发现了它的部分DNA。

Human diversity The chance of finding two people—who are not identical twins—with an identical DNA sequence is about the same as tossing a coin and getting heads six million times in a row. Try it! The human family Despite the variety, a huge amount of the human genome is the same across the world—99.9 percent of it! May contain Neanderthal! Most of us contain around 2 percent Neanderthal DNA from our extinct, ancient cousins. Variety is the spice of life! Individuals of every species of animal, plant, or microbe all have slightly different DNA sequences. This variation is called the gene pool. Larger gene pools make species better at surviving change. There are about 3,000,000 differences in the DNA sequences of any two people. Our genetic history DNA analysis can be used to trace human origins back to Africa. Diversity is great! If we were all the same, our species would be much less healthy! GENE POOLS Cheetahs are vulnerable to disease because they have a very small gene pool. About 12,000 years ago, they nearly died out. Only a few individuals survived, and a lot of genetic diversity was lost. Conservation programs run by zoos and other wildlife organizations try to preserve and expand the gene pools of threatened species.

人类的多样性 除了同卵双胞胎，找到两个DNA序列完全相同的人的概率，差不多等于连续抛六百万次硬币全是正面，几乎不可能。 一起来了解吧！ 人类大家庭 虽然每个人各有不同，但全世界所有人的基因组绝大部分都相同——相似度高达99.9%！ 你的身体里可能有尼安德特人基因哦！ 我们大多数人都携带着约2%的尼安德特人DNA，他们是我们已经灭绝的远古亲属。 多种多样才精彩！ 每种动物、植物、微生物的不同个体，DNA序列都存在细微差异。 这种差异集合就叫做基因库。 更大的基因库能让物种更适应环境变化，更容易存活下去。 任意两个人的DNA序列，大约有三百万处不同。 我们的基因历史 DNA分析可以追溯出，人类的起源在非洲。 多样性真的太棒啦！ 如果我们全都一模一样，人类这个物种会比现在脆弱不健康得多！ 基因库 猎豹很容易感染疾病，因为它们的基因库非常小。 大约一万两千年前，猎豹几乎灭绝。 只有少数个体存活下来，大量的基因多样性都消失了。 动物园和其他野生动物组织开展的保护项目，都在努力保护和扩大濒危物种的基因库。