How to Engineer Sustainable Chromosome Changes in Mice

Evolutionary chromosomal changes may take a million years in nature, but researchers are now reporting a novel technique enabling programmable chromosome fusion that has successfully produced mice with genetic changes that occur on a million-year evolutionary scale in the laboratory. The result may provide critical insights into how rearrangements of chromosomes—the tidy packages of organized genes, provided in equal number from each parent, which align and trade or blend traits to produce offspring—influence evolution.

In results published today in Science, the researchers reveal that chromosome-level engineering can be achieved in mammals, and they successfully derived a laboratory house mouse with novel and sustainable karyotype, providing critical insight into how  may influence evolution.

The laboratory house mouse has maintained a standard 40-chromosome karyotype—or the full picture of an organism’s chromosomes—after more than 100 years of artificial breeding,” said co-first author Li Zhikun, researcher in the Chinese Academy of Sciences (CAS) Institute of Zoology and the State Key Laboratory of Stem Cell and Reproductive Biology. “Over longer time scales, however, karyotype changes caused by chromosome rearrangements are common. Rodents have 3.2 to 3.5 rearrangements per million years, whereas primates have 1.6.”

Such small changes may have big impacts, according to Li. In primates, the 1.6 changes are the difference between humans and gorillas. Gorillas have two separate chromosomes whereas in humans they are fused, and a translocation between ancestor human chromosomes produced two different chromosomes in gorillas. At an individual level, fusions or translocations can lead to missing or extra chromosomes or even to such diseases as childhood leukemia.

Quantum Micro-Nano Satellite Launched by China

A Chinese micro-nano quantum satellite has entered its planned orbit and is now operational, the University of Science and Technology of China (USTC), one of its developers, said. It was launched atop a Lijian-1 carrier rocket from the Jiuquan Satellite Launch Center in northwest China.

The low-orbit satellite was designed to conduct real-time quantum key distribution experiments between the satellite and ground station and to carry out technical verification.

The new micro-nano satellite’s weight is about one-sixth the weight of the world’s first quantum satellite, the Chinese satellite Micius, which weighs more than 600 kilograms, according to the USTC. The university said that, based on the quantum technology first seen in Micius, it is clear that more low-cost quantum satellites are needed to realize an efficient, practical and global quantum communication network that can meet the increasing user demand.

The new satellite was jointly developed by Chinese universities and institutions such as the USTC, the Chinese Academy of Sciences and the Jinan Institute of Quantum Technology. Its launch and in-orbit operations are expected to aid the country’s quantum communication development and promote the improvement of national information security.

Nuclear Fusion One Step Closer

China broke the record by keeping the Experimental Advanced Superconducting Tokamak (EAST) by achieving plasma temperature at 120 million Celsius for 101 seconds and 160 million Celsius for 20 seconds, a major step toward the test run of the fusion reactor.

The Tokamak devise is located at the Hefei Institutes of Physical Science of the Chinese Academy of Sciences. It is designed to replicate the nuclear fusion process that occurs naturally in the sun and stars to provide almost infinite clean energy through controlled nuclear fusion, which is often dubbed the “artificial sun.” The achievement broke a previous record of maintaining the plasma temperature at 100 million C for 100 seconds. According to Li Miao, director of the physics department of the Southern University of Science and Technology in Shenzhen, it is a milestone in reaching the goal of keeping the temperature at a stable level for a long time.

The breakthrough is significant progress, and the ultimate goal should be keeping the temperature at a stable level for a long time,” Li told the Global Times, adding that the next milestone might be to maintain the stability for a week or more.

Achieving a plasma temperature above 100 million C is one of the key challenges to harness the nuclear fusion. At the end of 2020, South Korea reached 100 million C for 20 seconds. The temperature at the core of the sun is widely believed to be 15 million C, meaning that the plasma at the device’s core will be seven times hotter than that of the sun.
The energy generated from nuclear fusion is the most reliable and clean energy, Lin Boqiang, director of the China Center for Energy Economics Research at Xiamen University, told the Global Times on Friday, adding that if the technology can be applied commercially, it will have huge economic benefits. However, Lin cautioned that as the technology is still in the experimental stage, it still need at least 30 years for the technology to come out of the lab. “It’s more like a future technology that’s critical for China’s green development push.”


Smart Tumor-Targeting DNA NanoRobots

Chinese researchers have developed biodegradable tumor-targeting nanoparticles, which provides a promising therapy for tumor treatment, according to the Chinese Academy of Sciences (CAS).

A joint research team with scientists from the CAS developed the tumor-targeting nanoparticles as a combination of tumor-infarction therapy and chemotherapy, said the CAS.

It has long been a challenge for researchers to find a safe and effective therapy for vascular thrombosis. Drugs that induce thrombosis in the tumor vasculature have not resulted in long-term tumor eradication.

The CAS research team developed the nanoparticle, a type of DNA nanorobot that can precisely send the thrombin to the tumor-vessel walls and the tumor stroma, leaving the tumor to “starve to death.”

Study results showed that the co-administration of a cytotoxic payload and a protease to elicit vascular infarction in tumors with biodegradable tumor-targeting nanoparticles represented a promising strategy for improving the therapeutic index of coagulation-based tumor therapy.

The study has been published online by the journal Nature Biomedical Engineering.