As palaeontologists can tell, Neanderthals (尼安德特人) died out around 40,000 years ago. But they did not vanish from the Earth entirely. In the past decade it has become clear that Neanderthals mated with the ancestors of modern humans, and that some of those unions produced offspring (generations to follow). The result is that almost half of the Neanderthal genome survives, spread in small quantities among most modern people's DNA. The exception is those with mostly African ancestors, for Neanderthals seem never to have lived in Africa.
Such genes have been associated with everything from hairiness to fatness. Many seem to be related to the immune system, and to affect the risk of developing diseases including lupus, Crohn's disease and diabetes.
A pair of recent papers suggest Covid-19 belongs on that list as well. Two long DNA strings, both inherited from Neanderthals, appear to have resistance or sensibility to severe Covid-19, depending on which is present.
The work was led by Hugo Zeberg and Svante Paabo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, whose researchers pioneered the study of Neanderthal DNA.
Their first paper, published in Nature in September, described one Neanderthal DNA string, known as a “haplotype” (单体型), which is associated with a higher risk of serious illness.
Having one copy of the haplotype, which is found on the third of the 46 chromosomes possessed by humans, doubles the chances of a trip to intensive care. Those unlucky enough to possess two copies, one from each parent, face an even higher risk.
That genetic bad luck is not evenly distributed. It is most common among people of South Asia, with 63 per cent of the population of Bangladesh carrying at least one copy; and among Europeans, where the rate is around 16 per cent. As expected, it is almost absent from Africa. More strikingly, it is also very rare in Eastern Asia.
Exactly what the haplotype does is not clear. One gene within it affects a protein that interacts with the cellular receptors (细胞受体) that SARS-CoV-2 (the virus which causes Covid-19) uses to enter cells and control them.
The haplotype is also thought to be involved in the production of signalling proteins, called cytokines, which help to regulate the immune system. An overly aggressive immune response is one mechanism by which Covid-19 kills.
【小题1】Who are the most likely to carry the haplotype according to the study?A.Eastern Asians. | B.Africans. | C.Europeans. | D.South Asians. |
A.The haplotype is equally distributed among people in different races. |
B.Covid-19 kills partly because the immune system responds to SARS-CoV-2 abnormally. |
C.The haplotype appears to have resistance or sensibility to severe Covid-19. |
D.People unlucky to have two copies of the haplotype are sure to suffer from serious illness. |
A.Why the Neanderthal genome is related to a higher risk of serious illness. |
B.What effects the haplotype has on different people in different races. |
C.Why the haplotype makes people have a higher risk of Covid-19. |
D.What the haplotype does to affect and regulate the immune system. |
A.The second study on Covid-19. |
B.The previous study about Neanderthals. |
C.The other Neanderthal DNA string. |
D.The sensibility to severe Covid-19. |
Whether it’s for your health, environment — or your wallet — gardening has seen a boom in recent years.
Pick your own
Invite community conversations
Over the garden fence. At the vegetable fields. While weeding your window boxes.
Build strength
Gardening is exercise because you do small tasks like cutting grass or raking (耙地) that fall under the category of light or moderate exercise. However, you also dig, shovel, and chop wood to get this level up to moderate exercise.
Boost mood
Did you know that gardening can boost your mood while increasing your self-respect levels? When you make time to go out and work in your garden, your anxiety levels can go down and you could start to feel less depressed. One study looked at this benefit of gardening. There searchers took people who suffered from depression and had them participate in a 12-week long gardening.
A.The more you garden, the stronger you will get |
B.All of these tasks ensure you work your muscles |
C.There’s nothing like eating your own vegetables |
D.And now is a great time to get your hands dirty in soil |
E.A big benefit of gardening is forming connections with new people |
F.They found that each participant had great improvement in their condition |
G.It’s amazing to have someone to talk to when you’re tending your plants or vegetables |
Procrastination is one of the world’s worst time sucks: You have so much that you need to do, but when it comes to actually sitting down and getting it done, it seems basically impossible. But what if I told you that the opposite of procrastination, a phenomenon called pre-crastination, could be just as bad? A new study conducted by researchers from the University of Pennsylvania recently tackled the topic of pre-crastination — and it turns out that it could be a huge problem for many of us. If you’re wondering how the opposite of procrastination could be a negative thing, it’s because it means we’re completing tasks just for sake of completing them. Pre-crastination refers to the desire to do things immediately, but only to alleviate the anxiety surrounding leaving a particular task undone.
Let me give you an example: Say that you have to respond to an email. In your hurry to get the unread email out of your inbox, you make a bunch of spelling and grammar errors in your response because you typed it out so quickly. That would be an example of pre-crastination. I know that in my own life, I like to get through the easy tasks on my to-do list first, since they can be checked off more quickly, making me feel a lot more accomplished in the process. I just thought I was prioritizing, but I now know that this is an example of pre-crastinating the easy tasks just so I could say I got them done, while simultaneously procrastinating the more tedious tasks I left at the bottom of my list.
The discovery of pre-crastination leads to many kinds of questions about behavior. Now it seems that we have to not only worry about putting things off unnecessarily, but also doing things too quickly or completing easy tasks first just so that we can get them done.
The researchers touched on this in their article, published in Scientific American, in which they advise avoiding procrastination and pre-crastination by dividing your large tasks into smaller ones. That way, you can get through seemingly difficult tasks, but also avoid sliding through all of the simple ones first. I know that I’ll definitely be more careful when it comes to how I organize my to-do lit from now on.
【小题1】Which of the following things would you do if you suffered from pre-crastination?A.Prioritize the most difficult tasks. |
B.Try to beat the midnight deadline. |
C.Finish tasks at once with mistakes unchecked. |
D.Do nothing despite piles of matters to deal with. |
A.Anxious and impatient. | B.Ambitious and organized. |
C.Lazy and casual. | D.Strict and responsible. |
A.Valuable. | B.Exhausting. | C.Enjoyable. | D.Tough. |
A.Pre-crastination is as severe as procrastination. |
B.A person with procrastination will not suffer from pre-crastination. |
C.We should ignore simple tasks and put our heart and soul into difficult ones. |
D.The author doesn’t think it’s necessary to break tasks down and reschedule them. |
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