Abstract

Mammals can now be cloned artificially, but it remains unknown whether they can also maintain their species through cloning. Herein, we continued serial cloning for 20 years from a single donor mouse. These re-cloned mice appeared normal and had normal lifespans, but large structural and lethal mutations accumulated in their DNA with each generation. The birth rate of serial cloning began to decline from the 27th generation, and the 58th generation was the last. When re-cloned mice from near the final generation were mated with males, their oocytes could be fertilized, but most embryos degenerated. However, a few embryos were normalized by meiosis and fertilization and developed to full term, suggesting that mammals rely on sexual rather than asexual reproduction to eliminate genetic anomalies caused by clonal reproduction.

Based on the paper, it looks like there is a limit to mammalian cloning. I sort of wonder if species that reproduce slower, (primates,) would hit the cloning wall at an earlier generation?

Research.

Modern foods, many of them ultra-processed, are full of salt and if even more is added, the health risks this behavior poses are heightened. In 2021, 1.8 million deaths were attributed to salt-overuse worldwide. However, it is not always clear who is most likely to add extra salt. Investigating the habit of adding salt to food at the table, researchers found that men who are not on diets to manage high blood pressure are most likely to salt food after preparation. They also found that living arrangements and diet choices can significantly influence people’s discretionary salt use – but don’t do so in equal measure for men and women. The team highlighted the need to spread the word about alternative ways of enhancing flavor without adding salt.

T-4hrs from time of post

Research.

In a society increasingly shaped by self-checkouts, GPS navigation, and touchscreen ordering kiosks, new research shows face-to-face conversation may be quietly fading.

In everyday life, people often face choices between pursuing their own interests and cooperating with others. Cooperation helps individuals achieve shared goals and build positive relationships, but it often requires sacrificing some immediate personal benefit. Adolescence is a critical period during which young people learn how to manage friendships and collaborate in groups. Many studies have shown that teenagers tend to cooperate less than adults, but the reasons for this remain unclear. Do adolescents struggle to recognise when others are willing to cooperate, or do they recognise these intentions but choose to prioritise their own benefit?

Wu et al. aimed to understand why adolescents cooperate less than adults, both in their behaviour and in the decision-making processes that underlie it. Specifically, they examined whether adolescents fail to recognise cooperative behaviour from others, or whether they do recognise it but are more tempted than adults to take advantage of the situation for personal gain.

To investigate this, the researchers compared the behaviour of teenagers and adults in a repeated cooperation game. In this game, two players could either cooperate for mutual benefit or attempt to gain more for themselves at their partner’s expense. The results showed that teenagers cooperated less than adults, particularly after their partner had just cooperated. Importantly, teenagers and adults were equally accurate in estimating how cooperative their partner was. This suggests that adolescents recognise when others are willing to cooperate but feel less motivated to reciprocate.

These findings may help teachers, parents, and those designing school programmes better support teenagers’ social development. The study of Wu et al. suggests that it may be useful not only to help adolescents understand others’ intentions, but also to strengthen the value they place on fairness and on reciprocating cooperation when others behave kindly. Future research should explore whether similar patterns occur in real-life interactions and across more diverse groups of young people.

Archaeological finds aren’t always unearthed from the ground or recovered from caves and catacombs. Sometimes, they basically fall from the sky.

When a coffin crashed down from a cliff near the Baltic Sea near the village of Bagicz, Poland, in 1899, it was (unsurprisingly) the last thing anyone expected. Made from the hollowed trunk of an oak tree and exceptionally preserved, it protected the bones of a young woman from the ancient Wielbark culture who was thought at the time to have likely been a member of the social elite. She was buried with a bronze fibula, a necklace of glass and amber beads, a brooch, and bronze bar bracelets; was laying on a cowhide; and had a wooden stool at her feet.

Eventually, both she and her coffin found a new resting place in a museum, and were almost forgotten until the 1980s, when archaeologists rediscovered the partial skeleton with her coffin and grave goods. Even more recent investigations found that, though the burial appeared to be purposely set apart from other graves, it was unlikely the deceased was a princess or aristocrat—her burial was too similar to others from the Roman Iron Age in Poland. It only appeared that she been buried alone because her coffin had been exposed by coastal erosion.

Unknowns still lingered, however. Despite the grave goods being dated to the first half of the 2nd century C.E., analysis of the woman’s tooth showed that it was over a hundred years older. Archaeologist Marta Chmiel-Chrzanowska (who had previously studied the remains) was determined to find an answer to this puzzle of mis-matched dates, and she thought it might lie in the wood of the coffin. Dendrochronological dating would have been too invasive to carry out with older methods, which is why research on wooden Roman Iron Age artifacts in the region had been limited, but updates made it possible to date wood from much smaller samples. Chmiel-Chrzanowska was finally authorized to sample material from the coffin, and put the mystery of its age to rest.

“To determine whether this discrepancy is due to a reservoir effect or a misclassification of the finds, it was deemed necessary to conduct dendrochronological studies,” she said in a study recently published in the journal Archaeometry. “However, due to the unique nature of this discovery—the only preserved wooden sarcophagus of its kind from the Roman Iron Age—the primary concern was the risk of damage.”

Wilebark coffins were often made of hollowed tree trunks—something also seen in other burials of the ancient Slavic world, such as that of the famous Scythian “ice maiden.” Unfortunately, many Wielbark burials deteriorated and left little more behind than dark stains in the soil, which explains why this fallen burial was so rare.

Even rarer is the level of its preservation. This was made possible by the existence of an anoxic environment that prevented organic materials from degrading, which is thought to be the result of water levels rising and submerging coastal land. By sampling a section that included sapwood (the younger layers of a tree’s vascular tissues) and measuring the width of the growth rings, in addition to measuring the total annual growth rings, Chmiel-Chrzanowska and her team were able to date the wood to some time between 112 and 128 C.E.

Why exactly the radiocarbon dating of the tooth present in the remains suggested that the young woman had died a century before her coffin was made, however, still eluded the archaeologists. One theory is based on the fact that the nitrogen, oxygen and strontium content of her teeth and enamel suggested a diet high in animal protein. If at least some of that protein came from fish, the marine carbon—which contains lower levels of the carbon-14 isotope—could have artificially altered her perceived age. Another theory is that the woman could have been eating food that was not local, and while the molar studied reflected a diet local to the Baltic Sea basin where she lived, foreign food could have also had an aging effect.

“This finding is crucial for improving future radiocarbon dating interpretations, especially in regions with high water hardness,” said Chmiel-Chrzanowska. “Strontium and stable isotope analyses suggest that the woman may not have been a local inhabitant, raising questions about mobility and cultural exchanges in the Roman Iron Age.”