VOA慢速英语--New Techniques Let Scientists Study Cells

 

Until recently, when scientists studied cells from people and animals, they often had to examine large samples, producing an average of results from many kinds of cells.

The process was like trying to learn about bananas by studying a smoothie -- a drink made from different types of fruit.

In recent years, scientists have developed methods that let them directly study the activity of cells and the genetic² structure of individual cells. These techniques are now widely used and have provided information about how living organisms grow and develop. The techniques could also help scientists develop new treatments for diseases.

Single-cell revolution

A cell is any one of the very small parts that together form all living things. Cells each take on a job and work with their neighbors. In human beings, an average adult has around 37 trillion cells.

Single-cell analysis is the term for a group of techniques that scientists have developed for isolating³, or separating, cells from living organisms. Scientists can study genetic material in each cell and learn about the relationships between cells. The result, notes the journal Science, is that researchers can follow the development of people and other organisms in incredible detail.

Francis Collins is the director of the National Institutes of Health, or NIH, a medical research agency that is part of the U.S. Department of Health and Human Services. Collins recently noted⁴ the importance of such techniques for understanding human beings. “Single-cell analysis is crucial for a comprehensive understanding of our biology and health,” he said.

In fact, the journal Science named the techniques that permit single-cell tracking of gene¹ activity as its “breakthrough of the year” for 2018. “The single-cell revolution is just starting,” the publication declared.

More precise questions

Jonathan Weissman is a stem cell biologist at the University of California, San Francisco. He notes that single-cell analysis lets scientists ask much more detailed⁵, exacting⁶ questions than they could in the past. “It’s like a flight recorder, where you are watching what went wrong and not just looking at a snapshot at the end,” he said. “We can ask questions at a resolution that was just not possible before.”

Nicholas Navin is a professor with the MD Anderson Cancer Center at the University of Texas. He uses single-cell DNA⁷ studies to discover patterns of mutations in cells of a cancerous tumor⁹. These studies let Navin recreate when and where those mutations appeared as the tumor developed. That information helps him identify cells that contain combinations of mutations that make them the most deadly.

In the future, such research could be used to help identify what treatments to use for certain patients, Navin said. The research might also help doctors follow how well their treatments are working against a cancer over time. Ten to 20 years from now, Navin notes, doctors might be able to find cancers very early by identifying and studying the DNA of rare cells in blood tests.

Atlas¹⁰ of Cell Types

The ability to produce single-cell results for hundreds of thousands of cells at a time has created other new possibilities for researchers. One research group, the Human Cell Atlas Consortium, is creating a detailed listing of human cells. The research group, made up of more than 1,000 scientists from 57 countries, estimates it will eventually list at least 10 billion cells found in both healthy and sick people.

Aviv Regev is a biology professor at the Massachusetts Institute of Technology and a co-organizer of the project. Regev notes that the gene map has led scientists to identify genetic variants¹¹ that raise or lower the risk of many diseases. But to turn this information into treatments, scientists must know in which cells those variants act. “We have to map all of them,” she said.

Regev hopes for a first version of the planned cell atlas in about five years. To finish the job might take about 10 years, she estimates. “This is not going to cure all disease immediately,” she said, but “it is a critical stepping stone.”

I’m John Russell.

Words in This Story

analyze¹² – v.to study (something) closely and carefully; to learn the nature and relationship of the parts of (something) by a close and careful examination

breakthrough – n. a sudden increase in knowledge or understanding; an important discovery that happens after trying for a long time to understand or explain something

mutation⁸ – n. biology change in the genetic structure of a plant or animal that causes physical qualities that are different from what is normal

DNA– n. short for deoxyribonucleic acid.the carrier of genetic information

pattern– n. a model suggested for copying; something designed or used as a model

variant– n.one of two similar, but somewhat different things

sample– n.a representative part of something or a single object from a larger group

1 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

2 genetic   

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。

3 isolating   

adj.孤立的，绝缘的v.使隔离( isolate的现在分词 )；将…剔出（以便看清和单独处理）；使（某物质、细胞等）分离；使离析

参考例句：

• Colour filters are not very effective in isolating narrow spectral bands. 一些滤色片不能很有效地分离狭窄的光谱带。 来自辞典例句
• This became known as the streak method for isolating bacteria. 这个方法以后就称为分离细菌的划线法。 来自辞典例句

4 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

5 detailed   

adj.详细的，详尽的，极注意细节的，完全的

参考例句：

• He had made a detailed study of the terrain.他对地形作了缜密的研究。
• A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。

6 exacting   

adj.苛求的，要求严格的

参考例句：

• He must remember the letters and symbols with exacting precision.他必须以严格的精度记住每个字母和符号。
• The public has been more exacting in its demands as time has passed.随着时间的推移，公众的要求更趋严格。

7 DNA   

(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。

8 mutation   

n.变化，变异，转变

参考例句：

• People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
• So far the discussion has centered entirely around mutation in the strict sense.到目前为止，严格来讲，讨论完全集中于围绕突变问题上。

9 tumor   

n.（肿）瘤，肿块(英)tumour

参考例句：

• He was died of a malignant tumor.他死于恶性肿瘤。
• The surgeons irradiated the tumor.外科医生用X射线照射那个肿瘤。

10 atlas   

n.地图册，图表集

参考例句：

• He reached down the atlas from the top shelf.他从书架顶层取下地图集。
• The atlas contains forty maps,including three of Great Britain.这本地图集有40幅地图，其中包括3幅英国地图。

11 variants   

n.变体( variant的名词复数 )；变种；变型；（词等的）变体

参考例句：

• Those variants will be preserved in the'struggle for existence". 这些变异将在“生存竞争”中被保留下来。 来自辞典例句
• Like organisms, viruses have variants, generally called strains. 与其他生物一样，病毒也有变种，一般称之为株系。 来自辞典例句

12 analyze   

vt.分析，解析 (=analyse)

参考例句：

• We should analyze the cause and effect of this event.我们应该分析这场事变的因果。
• The teacher tried to analyze the cause of our failure.老师设法分析我们失败的原因。