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April 16, 2024

Science news in review: March 10

By VICKY ZHU | March 10, 2024



Gynandromorphism, a phenotypic trait where an animal has both male and female characteristics, is found in birds such as ducks, chickens and a green honeycreeper that was recently spotted in Colombia. 

As we approach the final stretch before spring break, let’s look beyond our class content and appreciate how scientists around the world have applied textbook knowledge to generate meaningful research findings. This week’s science news focuses on fascinating biodiversity in nature, humans’ impact on the environment and the potential to restore past lives on Earth. 

Microplastics accumulate in cells, affecting human health

Plastic is prevalent in our environment. As they break down, they create microplastics, which are smaller than a sesame seed.

Microplastics are minute enough to enter human cells and accumulate, as cells involved in regulating waste products cannot eliminate them. Therefore, microplastics have consequences on human health, such as oxidative stress, DNA damage and neurotoxicity if inhaled or ingested. A study showed that the presence of microplastics in arteries increased the risk of heart attack by 4.5 times. 

Microplastics are known to have an affinity for accumulating in fat molecules. A recent study examined the microplastic content in plaques collected from patients undergoing carotid endarterectomy. The most common form of plastic in the plaques was polyethylene, a form of plastic used in food containers, bags and bottles. 

In comparison with patients whose plaque samples had no microplastics, those that had microplastics were more likely to: be younger, be male, have a history of smoking and have diabetes or cardiovascular disease. 

The researchers hope their study can contribute to facilitating global efforts to eliminate plastic contamination. 

De-extinction company modified elephant skin cells as a step toward making a mammoth

Existing research efforts have created pluripotent stem cells from endangered animals such as the northern white rhinoceros and the snow leopard. However, obtaining such cells from elephants has been challenging. 

Colossal, a de-extinction company in Texas, recently converted elephant cells into pluripotent stem cells, meaning that they have the potential to differentiate into specialized cell types. Although they initially encountered the same obstacles of working with elephant cells, they discovered a crucial step specific for elephant cells — reducing expression of TP53, a gene involved in cell division and death. 

Asian elephants are the closest living relative to extinct mammoths. Colossal’s plan is to create genetically engineered Asian elephants with mammoth traits. The ability to create pluripotent stem cells from elephant skin cells is a step forward; however, substantial technological advances are necessary to realize this goal. 

Anthropocene is rejected as a geological epoch on Earth

Geologists divide the Earth’s history into epochs, which are characterized by crucial geological events and the emergence or distinction of important life forms. As human activities started to create large impacts on the Earth, the term Anthropocene has been coined to describe the period of immense irreversible man-made changes on Earth. 

However, the Anthropocene was rejected as an official epoch by the majority on a vote at the Subcommission on Quaternary Stratigraphy on March 5. Although 12 members voted for rejecting Anthropocene, the four members that voted against it claimed in a press statement the next day that the voting occurred as a contravention of the commission’s statutes. The debate about the result of the vote is still ongoing. 

This proposal to start the Anthropocene would end the Holocene, which started 11,700 years ago after the Little Ice Age, and mark the beginning of the Anthropocene as 1952, when plutonium sediments from hydrogen bomb tests appeared in Crawford Lake near Toronto

The Anthropocene has become an important cultural concept in conversations about climate change, global warming and biodiversity preservation. Many scholars have worked hard to accumulate evidence such as fossil fuels, deforestation and ocean acidification at various sites to elucidate the extensive human impact on the Earth’s geology and other living things. Supporters of the new epoch claim that the Anthropocene could raise more awareness and initiate more actions to minimize man-made damages to the Earth; however, its recognition as an epoch is still under further debate and votes. 

Marveling fascinating biodiversity on Earth

An amphibian species that lays eggs outside the body produces a nutritious liquid when offspring bite on the mother’s skin. Siphonops annulatus is a species of caecilians, which are worm-like and limbless amphibians. 

The researchers filmed 16 hatching Siphonops annulatus in Brazil and analyzed more than 200 hours of behavior in detail. They found that the offspring’s munching stimulated the production of a liquid rich in fat and carbohydrates. This can be analogous to lactation in mammals

In Colombia, an evolutionary biologist from New Zealand spotted a gynandromorph green honeycreeper, meaning it has both male and female phenotypic traits. Half of the bird’s body has a typical male feather color, and the other half has a typical female feather color. In addition to the green honeycreeper, gynandromorphism has been observed in other birds, such as chickens and ducks, as well as insects and crustaceans. 

A theory behind gynandromorphism is the incomplete separation of the sex chromosomes during egg formation in birds. Unlike humans, female birds have two different sex chromosomes, W and Z, while male birds have two Z chromosomes. If a fused egg cell with both W and Z chromosomes is fertilized by a sperm carrying Z, the resulting zygote would undergo cell division that produces ZZ and ZW cells in the same organism.

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