1 . In the genetic age, ecologists’ jobs are made much easier by two things. One is that every organism carries its own chemical identity card, in the form of its genome (基因组). The second is that they drop these ID cards everywhere they go. Urine, bits of fur stuck to a hedge, even shed skin cells: all deposit DNA into the environment. Cheap gene sequencing allows scientists to harvest this “environmental DNA” (eDNA) from soil, sand, water and the like, and use it to keep track of which species are living where.
“Every organism,” of course, includes humans. In a paper published on May 15th in Nature Ecology & Evolution, a group of researchers from America and Europe report that such eDNA surveys pick up large quantities of human DNA as well as the animal sort. That DNA can be read—and potentially matched with individuals—by anyone with the right equipment.
The researchers did not set out to study “inadvertent human genetic bycatch”, as they call the phenomenon. The work began at the Witney Sea Turtle Hospital in Florida, during an investigation into a viral turtle disease. The researchers sampled water from the turtle’s tanks, as well as from ocean water and beaches upon which the creatures nested, looking for viral DNA.
They expected to sweep up DNA from other species during their trawl (拖网). What was surprising, according to Jessica Farrell, a biologist at the Witney Hospital and one of the paper’s authors, was just how much human DNA they found. Even though many of their sampling sites were not near towns and cities, they found human genetic material in every sample they examined.
Interested, they expanded their search. In both Florida and in Ireland they found human DNA in rivers, with concentrations especially high as they flowed through towns. They found it in beach sand, and even in air from rooms in which humans had been working. Human DNA is not quite everywhere: it was not detectable in deep ocean water, or on remote beaches closed to the public. But anywhere that humans are, their DNA appears to be as well.
In one sense, that is unsurprising. But advances in gene-sequencing meant there was enough information in the samples to deduce plenty of things about the humans in question. The researchers could pick out males thanks to DNA from the Y chromo some. They could infer an individual’s ancestry, and even spot mutations (突变) that affect a person’s disease risk. David Duffy, another of the paper’s authors, said the amount and quality of the DNA they recovered “far exceeded” the minimum necessary to be included in America’s database of missing people. Dr Duffy and his colleagues did not try to identify individuals in their study, for moral reasons. But they had no doubt it could be done.
1. Which of the following about eDNA is true according to the passage?A.It provides a way to track the migration of animals. |
B.It allows researchers to restore individual organisms. |
C.It can be easily collected from all types of environments. |
D.It contains a wealth of genetic information about various species. |
A.familiar | B.accidental | C.insensitive | D.regular |
A.The application of eDNA for identity confirmation has aroused concern. |
B.As expected, the researchers detected much human eDNA in their search. |
C.An individual’s gender and ancestry can be confirmed by means of eDNA. |
D.eDNA is instrumental in upgrading America’s database of missing people. |
A.Unintended Discoveries in Turtle Disease Research |
B.The Ecological Significance of Environmental DNA |
C.Human DNA’s Prevalence in Environmental Samples |
D.Using Genetic Information to Identify Missing Persons |
2 . On our 20th anniversary, Susan and I headed off for a few days to a lovely valley about an hour away. We didn’t know much about the town, but that was fine. Our goal was really just to renew our faith in each other.
We began by stocking up at the quirky Village Market in Glen Ellen, California. Within minutes, friendly locals spotted us and started chatting in the aisles with charming tips. You gotta hike to Jack London’s house. Oh, dinner at the Fig Café. Hours later, having followed their yellow brick road all day, we walked, delirious, back from dinner to our creekside inn. “I think I could live here,” Susan said.
It turns out that Glen Ellen’s contagious spirit was not our passing illusion. In October 2017, the Nuns Fire bore down on this town near Santa Rosa. An astounding 183 of Glen Ellen’s 750 or so homes burned down. Among them was Jill Dawson’s place, just across the creek from the inn to which we had returned the next anniversary, and four more in turn. I called Jill after reading her family’s story. She sounded just like the spirited, generous type Susan and I have loved meeting in Glen Ellen.
After the fire, she told me, her family’s prospects for staying in the town looked bleak. But residents mobilized on Facebook and in the Village Market to brainstorm how to house one another.
Hearing of their plight, some neighbors who barely knew the Dawsons placed two new trailers next to their house, which hadn’t burned, for Jill’s family.
“Their name is the Fosters, and I tell them, ‘You just can’t help it,’” Jill says, laughing at her own pun. Jill and her husband, Art, have lived in one of the trailers for a year while sorting through how to rebuild. They are only two of the many residents who were able to remain close thanks to their neighbors’ selflessness. “I’m grateful for little Glen Ellen,” Jill says. “The amount of passionate people and grassroots efforts working to keep this place supportive is amazing. The kindness thing, it’s still huge here.”
In kicking off our annual Nicest Place in America search, let Glen Ellen be just one example. So many cities, workplaces, churches, schools, and other locations thrive because, well, “the kindness thing, it’s still huge.” Please take the time to go to RD.COM/NICEST to tell us about one you love. Thank you!
1. What did the author think of Glen Ellen during his several trips there?A.He found Glen Ellen to be a dynamic town with rapid development. |
B.He had mixed feelings about Glen Ellen, both positive and negative. |
C.He thought Glen Ellen was a place which deepened faith in her wife. |
D.He developed a positive impression of its welcoming community spirit. |
A.They relied solely on government aid for recovery efforts. |
B.They spontaneously formed a neighborhood watch program. |
C.They held a series of fundraisers to help the affected families. |
D.They largely depended on assistance from distant communities. |
A.Jim is making a lighthearted comment about the Fosters’ inborn generosity. |
B.Jill is implying that Fosters lack competence to give a helping hand to others. |
C.Jill is hinting that the Fosters might not always display the same level of kindness. |
D.Jill is expressing his sincere gratitude for Fosters’ constant and generous assistance. |
A.To highlight Glen Ellen’s tradition of community support and kindness. |
B.To demonstrate the author’s personal perspectives in community building. |
C.To present how people in Glen Ellen overcame difficulties with joint efforts. |
D.To encourage readers to reflect on and share their own experiences of kindness. |
3 . In 1919, in the aftermath of war, the International Labour Organization used its first convention to limit working hours to eight a day and 48 a week. The Depression later prompted employers to
The latest crisis is dealing a
Promised
Offsetting the cost of a four-day week at a national level looks
The Wellcome Trust, the science research foundation, decided in 2019 that even a trial would be
Lockdowns exposed the gap between flexible homeworking professionals and front-line “
Some staff want or need to work extra hours. To the risks of a two-tier workforce and reduced freedom of choice add the danger of
For each of these
A.cancel | B.restore | C.back | D.deny |
A.similar | B.mild | C.psychological | D.distinct |
A.stopping | B.considering | C.continuing | D.forbidding |
A.features | B.awards | C.challenges | D.benefits |
A.therefore | B.however | C.besides | D.otherwise |
A.optimistic | B.essential | C.hard | D.instant |
A.capping | B.eliminating | C.revising | D.promoting |
A.effective | B.troublesome | C.consequential | D.apparent |
A.Professionals | B.Full-timers | C.Amateurs | D.Part-timers |
A.industrious | B.goal-driven | C.always-on | D.decisive |
A.widen | B.bridge | C.fill | D.leave |
A.boredom | B.invasion | C.distraction | D.overload |
A.short | B.long | C.early | D.late |
A.distinctions | B.impacts | C.objections | D.suggestions |
A.judgment | B.standard | C.management | D.method |
The Impact of Visual Cues on Behavior
During the energy crisis in the 1970s, Dutch researchers began to pay close attention to the country’s energy usage. In one suburb near Amsterdam, they found that some homeowners used 30 percent less energy than their neighbors
It turned out that the houses in this neighborhood were nearly identical except for one feature: the location of the electrical meter. Some had one in the basement.
Every habit
By comparison, creating obvious visual cues can draw your attention toward a
Eventually, I took my own advice and redesigned my environment. I bought a large display bowl and placed it in the middle of the kitchen counter. The next time I bought apples, that was
A.Open. | B.Selfish. | C.Friendly. | D.Reserved. |
A.They stay quiet. |
B.They read a book. |
C.They talk about the weather. |
D.They chat with fellow passengers. |
A.She was always treated as a foreigner. |
B.She was eager to visit an English castle. |
C.She was never invited to a colleague’s home. |
D.She was unwilling to make friends with workmates. |
A.Houses are much quieter. |
B.Houses provide more privacy. |
C.They want to have more space. |
D.They want a garden of their own. |
A.Alert. | B.Unfocused. | C.Awake. | D.Busy. |
A.They are solution providers. |
B.They are a source of inspiration. |
C.They are normally full of bad news. |
D.They are more educational than websites. |
A.Drink more coffee. |
B.Scroll through news websites. |
C.Allow ourselves some time to relax. |
D.Release our stress with constant complaints. |
A.He was laughed at by other students. |
B.He was interested in studying in his youth. |
C.He got his graduate degree at the age of 60. |
D.He made his fellow students more open-minded. |
A.Considerate. | B.Independent. | C.Intelligent. | D.Energetic. |
A.It is never too late to learn. |
B.Two heads are better than one. |
C.A friend in need is friend indeed. |
D.You can’t teach an old dog new tricks. |
A.The woman may need to reevaluate her priorities. |
B.The woman should deal with the urgent matters first. |
C.The woman has failed to take care of the urgent matters. |
D.The woman should keep track of everything using a to-do list. |
A.Three. | B.Six | C.Nine. | D.Twelve. |
A.In a library. | B.In a bookstore. |
C.In an office. | D.In a furniture store. |