DNA测试准吗?
文章来源:未知 文章作者:enread 发布时间:2020-09-22 01:55 字体: [ ]  进入论坛
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Have you ever wondered why your brother or sister doesn’t look exactly like you despite having the same family tree? If you think that’s odd, even stranger is the idea that you and your sibling1 may have very different ancestry2 genes3. You have the same parents, and therefore the exact same ancestors, but somehow your DNA4 tests come back with very different results. How is this even possible?
 
Children inherit half of their DNA from each parent, via the sperm5 from the father and the egg from the mother. Our bodies contain 46 chromosomes6, or 23 pairs. However, each reproductive cell has only 23 individual chromosomes. When the bodies of our forbearers created their sex cells, the cells engaged in genetic7 reshuffling, meaning each of the 23 chromosomes is a unique combination of an original pair. This process is also called genetic recombination.  
 
This is why Dr. Prosanta Chakrabarty, a scientist who studies fish to help explain the evolution of human beings and our planet, says that your sister could be 10% more 'French' than you, despite having the same primogenitors. And the further you go back in your lineage, the more confusing it can be.
 
You inherit 25% of each grandparent's DNA. However, this process of recombination means that inevitably8 some of their genetic make-up will be lost along the way. This could mean that the genes you inherited from your grandparent, could be completely different to those your cousin received.  
 
Those studying genealogy9 should also be aware that modern DNA testing might not give you an accurate idea of your ancestry as it is tested against a current, but incomplete database. Many of the genetic samples come from North America and Western Europe. The genes passed down from your ancestors is sampled and matched with people who originated from a certain area. However, without enough samples from the Middle East or Africa, the results may be inaccurate10.
 
Dr. Prosanta Chakrabarty says that only 1% of our genetic make-up is unique to us, and that it is an incomplete mash-up of our ancestors'. So, the next time someone says you look a bit like you're from a certain country, you may well be. But it might not show up in your tests.


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1 sibling TEszc     
n.同胞手足(指兄、弟、姐或妹)
参考例句:
  • Many of us hate living in the shadows of a more successful sibling.我们很多人都讨厌活在更为成功的手足的阴影下。
  • Sibling ravalry has been common in this family.这个家里,兄弟姊妹之间的矛盾很平常。
2 ancestry BNvzf     
n.祖先,家世
参考例句:
  • Their ancestry settled the land in 1856.他们的祖辈1856年在这块土地上定居下来。
  • He is an American of French ancestry.他是法国血统的美国人。
3 genes 01914f8eac35d7e14afa065217edd8c0     
n.基因( gene的名词复数 )
参考例句:
  • You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因,所以能够活得很长。 来自《简明英汉词典》
  • Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪
4 DNA 4u3z1l     
(缩)deoxyribonucleic acid 脱氧核糖核酸
参考例句:
  • DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
5 sperm jFOzO     
n.精子,精液
参考例句:
  • Only one sperm fertilises an egg.只有一个精子使卵子受精。
  • In human reproduction,one female egg is usually fertilized by one sperm.在人体生殖过程中,一个精子使一个卵子受精。
6 chromosomes 11783d79c0016b60332bbf1856b3f77d     
n.染色体( chromosome的名词复数 )
参考例句:
  • Chromosomes also determine the sex of animals. 染色体也决定动物的性别。 来自《简明英汉词典》
  • Each of four chromosomes divide longitudinally. 四种染色体的每一种都沿着纵向分裂。 来自《现代汉英综合大词典》
7 genetic PgIxp     
adj.遗传的,遗传学的
参考例句:
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
8 inevitably x7axc     
adv.不可避免地;必然发生地
参考例句:
  • In the way you go on,you are inevitably coming apart.照你们这样下去,毫无疑问是会散伙的。
  • Technological changes will inevitably lead to unemployment.技术变革必然会导致失业。
9 genealogy p6Ay4     
n.家系,宗谱
参考例句:
  • He had sat and repeated his family's genealogy to her,twenty minutes of nonstop names.他坐下又给她细数了一遍他家族的家谱,20分钟内说出了一连串的名字。
  • He was proficient in all questions of genealogy.他非常精通所有家谱的问题。
10 inaccurate D9qx7     
adj.错误的,不正确的,不准确的
参考例句:
  • The book is both inaccurate and exaggerated.这本书不但不准确,而且夸大其词。
  • She never knows the right time because her watch is inaccurate.她从来不知道准确的时间因为她的表不准。
TAG标签: DNA genes tests
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