Common sense suggests that the bigger the animal, the greater number of cells—and therefore the greater chance of developing cancer. However, in the 1970s an Oxford University professor, Richard Peto, found that: the bigger animal, the less cancer. 

Scientists call it Peto’s paradox: cancer is caused by gene mutations(突变) that increase in cells over time, yet long-lived animals that have lots of cells, such as elephants and whales, hardly ever get it. Why? For elephants, at least, part of the answer may be the gene commonly known as p53, which also helps humans and many other animals repair DNA damaged during replication(复制). Elephants have an amazing 20 copies of this gene. Those copies, each with two variations called alleles, produce a total of 40 proteins, compared with humans’ and most animals’ single copy producing two proteins.

New research in Molecular Biology and Evolution looks into how elephants’ many copies offer cancer-fighting advantages. The work “opens many new possibilities to study how cells protect themselves from a damaged genome,” says co-author Robin Fåhraeus, a molecular oncologist at France’s National Institute of Health and Medical Research. In mammals, p53 plays a significant role in preventing mutated cells from turning into tumors. It works by pausing replication and then either starting repair or causing cells to self-destroy if the damage is huge. Without action from p53, cancer can easily take hold.

The scientists modeled and examined elephants’ 40 p53 proteins finding two ways the gene could help elephants avoid cancer. First, that elephants possess multiple copies lowers the chance of p53 no longer working because of mutations. Additionally, elephants’ p53 copies activate in response to varying molecular triggers(触发器) and so respond to damaged cells differently, which likely gives an edge when detecting and clearing away mutations.

These “remarkable” results imply that elephants have a series of means through which p53 can operate. This points to exciting possibilities for exploring powerful new approaches to cancer protection in humans.

【推荐2】A narrow region of the eastern Pacific Ocean has been getting colder for the past 30 years, challenging global trends and confusing many scientists. Over at least three decades, the region has cooled by roughly half a degree, which has been causing scientists to wonder how long that will hold.

The unusual phenomenon, known as the “cold tongue” is affecting a vast area of ocean west of South America. Scientists are not entirely certain what is keeping the “cold tongue” cool. Richard Seager, from the Earth Observatory at Columbia University, said one factor appears to be trade winds in the equatorial (赤道) region, which carry warm water away from the surface, stimulating cooler water to rise. “The trade winds blow from east to west across the tropical Pacific Ocean,” Seager said. “As the waters are driven away from the surface, water flows up from below. And since the waters below the surface are cold, this creates the ‘cold tongue’.”

Yet despite the effect of these winds, the “cold tongue” has puzzled scientists, because advanced climate computer models suggest that the waters should have been warming for decades at a faster rate than the rest of the Pacific due to rising greenhouse gas emissions (排放).

Pedro DiNezio of the University of Colorado Boulder, considers “It’s the most important unanswered question in climate science”. Scientists can’t predict when it will end or start warming since the cause is unknown. According to New Scientist, this has huge worldwide implications, including determining California’s permanent drought and Australia’s wildfires. More profoundly still, “it could even alter the extent of climate change globally”, the site said, “by understanding how sensitive Earth’s atmosphere is to rising greenhouse gas production”.

Despite this, the overall ocean temperatures are rising. Solving the puzzle of the “cold tongue” isn’t about proving climate models wrong. Rather, the “cold tongue” is the last big piece of the puzzle. Fit that in and we can build a more accurate picture of how life will change in a warming world-and how best to prepare for that future.

【推荐3】Mars is truly a fascinating planet for those of us here on Earth.     1     It is about half as big as Earth and is often referred to as the Red Planet because of its red surface.

The Red Planet has the largest volcano in the solar system-Olympus Mons.     2     That’s about three times the height of Mount Qomolangma.

Mars also has an atmosphere, but it is very thin and made up mostly of carbon dioxide. Because of its thin atmosphere and greater distance from the Sun, Mars is much colder than Earth.     3     The dust storms of Mars can grow so big that sometimes they blanket the entire planet and last for months. The poles on Mars are a lot like Antarctica, capped by ice, but much of Mars’s ice is made from carbon dioxide, not water.

Scientists believe that studying Mars can help answer some of the key questions about our planet Earth, or even the universe.

    4     Since 1960, more than half of all attempted Mars missions have failed. The USA, Russia, the European Space Agency, and several other countries have lost many spacecraft in their quest to explore the Red Planet. Nevertheless, they will still continue their explorations. Chinese experts are confident about their plan to explore Mars, in spite of the many challenges. The first Mars unmanned spacecraft was launched from Wenchang around 2020. But it is only the beginning of deep voyages into outer space.     5