Scientists at Academia Sinica have identified a new form of cell division that occurs without the replication of DNA, challenging the scientific consensus on one of the most basic biological processes.
Since the 19th century, scientists have known of only two main types of cell division in animals — meiosis in germ cells (sperm or egg cells) and mitosis in somatic cells, which comprise all other cells in the body.
However, in a new paper published in the British scientific journal Nature, an Academia Sinica team described a previously unknown form of cell division which, unlike mitosis, does not involve the duplication of DNA.
Photo courtesy of Academia Sinica
The team, led by Chen Chen-hui (陳振輝), an assistant research fellow at the academy’s Institute of Cellular and Organismic Biology, held a news conference on Monday to explain their findings.
To conduct the research, Chen’s team used a custom-made computer tagging system to color and track individual cells on zebrafish larvae as they developed.
To do so, the researchers had to catch and anesthetize the 0.5cm fish every 12 hours and photograph them under a high-powered microscope.
They discovered that during a specific stage in the fishes’ growth, some of the outer layers of their skin cells underwent up to two rounds of cell division (one cell becoming four cells) by splitting, rather than duplicating, their DNA.
The phenomenon, called asynthetic fission, is a temporary measure used to expand the coverage of epithelial cells, or outer skin cells, during a period of rapid growth, Chen said.
According to a video produced by Nature, the process happens so quickly that cells even appeared to make “mistakes,” such as not cleanly separating the DNA between the new cells.
However, within a few weeks the zebrafish get rid of the unusual cells and replace them with regular cells containing normal amounts of DNA, the video said.
While the team is still in the early stages of understanding the process, this mode of cell proliferation might occur in contexts beyond zebrafish skin expansion, Chen said.
The article, titled Skin cells undergo asynthetic fission to expand body surfaces in zebrafish, was published on Wednesday last week.
The journal’s video on the research, A new kind of cell division, was released on Sunday.
Taiwanese were praised for their composure after a video filmed by Taiwanese tourists capturing the moment a magnitude 7.5 earthquake struck Japan’s Aomori Prefecture went viral on social media. The video shows a hotel room shaking violently amid Monday’s quake, with objects falling to the ground. Two Taiwanese began filming with their mobile phones, while two others held the sides of a TV to prevent it from falling. When the shaking stopped, the pair calmly took down the TV and laid it flat on a tatami mat, the video shows. The video also captured the group talking about the safety of their companions bathing
US climber Alex Honnold is to attempt to scale Taipei 101 without a rope and harness in a live Netflix special on Jan. 24, the streaming platform announced on Wednesday. Accounting for the time difference, the two-hour broadcast of Honnold’s climb, called Skyscraper Live, is to air on Jan. 23 in the US, Netflix said in a statement. Honnold, 40, was the first person ever to free solo climb the 900m El Capitan rock formation in Yosemite National Park — a feat that was recorded and later made into the 2018 documentary film Free Solo. Netflix previewed Skyscraper Live in October, after videos
Starting on Jan. 1, YouBike riders must have insurance to use the service, and a six-month trial of NT$5 coupons under certain conditions would be implemented to balance bike shortages, a joint statement from transportation departments across Taipei, New Taipei City and Taoyuan announced yesterday. The rental bike system operator said that coupons would be offered to riders to rent bikes from full stations, for riders who take out an electric-assisted bike from a full station, and for riders who return a bike to an empty station. All riders with YouBike accounts are automatically eligible for the program, and each membership account
A classified Pentagon-produced, multiyear assessment — the Overmatch brief — highlighted unreported Chinese capabilities to destroy US military assets and identified US supply chain choke points, painting a disturbing picture of waning US military might, a New York Times editorial published on Monday said. US Secretary of Defense Pete Hegseth’s comments in November last year that “we lose every time” in Pentagon-conducted war games pitting the US against China further highlighted the uncertainty about the US’ capability to intervene in the event of a Chinese invasion of Taiwan. “It shows the Pentagon’s overreliance on expensive, vulnerable weapons as adversaries field cheap, technologically
RSS