Comment

Comment by Dr. Krishna Kumari Challa on February 18, 2026 at 2:55pm

Imagine that there are two human tribes. In one, members are solely focused on their individual success. In the other, members are willing to sacrifice themselves for the good of the whole; however, this altruism may cost them time and resources that they could expend on their own children and personal survival.

Which tribe is more likely to survive a crisis, such as an attack from another group? The second.
Paradoxically, the willingness for an individual to sacrifice for the group can lead to better survival outcomes. That doesn't mean that everyone in a group will become self-sacrificing, but that groups with self-sacrificing individuals may have a survival advantage.
To take a broader view, individuals not only live in communities but are communities. We are composed of trillions of cells, which comprise our tissues and organs, along with the bacteria in our microbiome and the viruses that afflict us. We live in families, neighborhoods, and countries, as well as ecosystems that bring us into contact with other species.

Every single one of these systems can change over time in response to stimuli, shifting and adapting in response to one another. Groupings can also influence individual success; consider, for example, the case of a family struggling with systemic poverty, or the impact of a troubled neighborhood on the individuals within it.Cancer is another interesting example, as are viral illnesses. On one hand, cancer cells no longer cooperate with the rest of the body, subverting the communal good for their individual benefit. But the situation isn't so cut-and-dry.

"In some cases, cancer cells act as a cooperative group in their own right; the ways they spread are strategic. You can also get competition between diseases for host resources
But what happens within a host is not the whole story; the host's environment is critical, too. If a communicable disease exists in a host population with frequent and predictable contacts, rapid growth with damage to a host may evolve, because this will not stop the host from passing it on.

However, such diseases would soon die out in populations of more isolated individuals; in the second scenario, more benign versions would have the advantage, because longer surviving hosts would give the host—and its virus or bacteria—time to find another host. Thus, selection within hosts may favor disease organisms that reproduce faster, but selection between the groups of disease organisms defined by each host may be in the exact opposite direction.
Multilevel selection complicates the picture because you have to consider all the places where selection could be occurring, and it's possible that selection on one level is headed in a different direction than selection on another level
Part 2

Comment by Dr. Krishna Kumari Challa on February 18, 2026 at 2:51pm

Beyond 'survival' of fittest: Evolution works in teams
Natural selection operates at multiple levels of biological organization, not just at the individual level. Empirical evidence from diverse species demonstrates that traits can be favoured or suppressed through both individual and group-level selection, sometimes in opposing directions. Recognizing multilevel selection provides a more comprehensive understanding of evolutionary processes and has practical implications in fields such as medicine and agriculture.
The common view of natural selection is based solely on the individual: A trait allows an organism to out-compete its rivals and is thus passed down to its offspring. To suggest otherwise can provoke the ire of certain segments of the scientific community.
But a bibliometric review of 280 scientific studies shows that natural selection can occur on multiple levels of biological organization simultaneously, and not just in social species.
The idea of looking at selection at multiple levels is to measure whether a trait is adaptive for individuals within a group. And does the frequency or existence of that trait within a group change the way the group functions in comparison with other groups?
The studies examined by the researchers spanned more than a century, covering everything from viruses to human beings. All attempted to account for multilevel selection (MLS), which provides a broader view of natural selection than individual benefit.
Why does multilevel selection remain controversial? Scientific culture. Since the 1960s, key scientists have observed that claims of group benefits weren't subject to rigorous measurement and shouldn't be taken seriously. Some scientists openly banned discussion of group selection in their classrooms, calling it naïve; others claimed that it was exceedingly rare or another term for kin selection.
If you measure the average increase in the frequency of a trait over generations and then say it's favoured by natural selection, you're not wrong
But what's the mechanism for the slow increase in that trait over here and the rapid increase over there?
If you had looked at different levels, you might see that group competition is more important in one place, or cooperation within groups in another.
Part 1

Comment by Dr. Krishna Kumari Challa on February 18, 2026 at 9:21am

SC65A.3 is the first Psychrobacter strain for which resistance to certain antibiotics—including trimethoprim, clindamycin, and metronidazole—was found. Those antibiotics are used to treat UTIs, infections of lungs, skin, or blood, and the reproductive system. SC65A.3's resistance profile suggests that strains capable of surviving in cold environments could act as reservoirs of resistance genes, which are specific DNA sequences that help them survive exposure to drugs.
Bacterial strains like the one examined here hold both a threat and a promise. "If melting ice releases these microbes, these genes could spread to modern bacteria, adding to the global challenge of antibiotic resistance.
On the other hand, they produce unique enzymes and antimicrobial compounds that could inspire new antibiotics, industrial enzymes, and other biotechnological innovations.
In the Psychrobacter SC65A.3 genome, the researchers found almost 600 genes with unknown functions, suggesting a yet untapped source for discovering novel biological mechanisms. Analysis of the genome also revealed 11 genes that are potentially able to kill or stop the growth of other bacteria, fungi, and viruses.
These ancient bacteria are essential for science and medicine.

First genome sequence and functional profiling of a Psychrobacter SC65A.3 preserved in 5,000-year-old cave ice: frominsights into ancient resistome, to antimicrobial potential and enzymatic activities, Frontiers in Microbiology (2026). DOI: 10.3389/fmicb.2025.1713017

Part 2

Comment by Dr. Krishna Kumari Challa on February 18, 2026 at 9:19am

The Universe throws surprises at us all the time!

Bacterial strain from 5,000-year-old cave ice shows resistance against 10 modern antibiotics

Bacteria have evolved to adapt to all of Earth's most extreme conditions, from scorching heat to temperatures well below zero. Ice caves are just one of the environments hosting a variety of microorganisms that represent a source of genetic diversity that has not yet been studied extensively. Now, researchers tested antibiotic resistance profiles of a bacterial strain that until recently was hidden in a 5,000-year-old layer of ice of an underground ice cave—and found it could be an opportunity for developing new strategies to prevent the rise of antibiotic resistance and study how resistance naturally evolves and spreads. They reported their discovery in Frontiers in Microbiology.

The Psychrobacter SC65A.3 bacterial strain isolated from Scarisoara Ice Cave, despite its ancient origin, shows resistance to multiple modern antibiotics and carries over 100 resistance-related genes. But it can also inhibit the growth of several major antibiotic-resistant 'superbugs' and showed important enzymatic activities with important biotechnological potential.

Psychrobacter SC65A.3 is a strain of the genus Psychrobacter, which are bacteria adapted to cold environments. Some species can cause infections in humans or animals. Psychrobacter bacteria have biotechnological potential, but the antibiotic resistance profiles of these bacteria are largely unknown.

Studying microbes such as Psychrobacter SC65A.3 retrieved from millennia-old cave ice deposits reveals how antibiotic resistance evolved naturally in the environment, "long before modern antibiotics were ever used".

The team drilled a 25-meter ice core from the area of the cave known as the Great Hall, representing a 13,000-year timeline. To avoid contamination, the ice fragments taken from the core were placed in sterile bags and kept frozen on their way back to the lab. There, the researchers isolated various bacterial strains and sequenced their genome to determine which genes allow the strain to survive in low temperatures and which confer antimicrobial resistance and activity.

They tested for resistance of the SC65A strain against 28 antibiotics from 10 classes that are routinely used to or reserved for treating bacterial infections, including antibiotics that have previously been identified to possess resistance genes or mutations that give them the ability to resist drug effects. This way, they could test whether predicted mechanisms translated into measurable resistance.

The 10 antibiotics they found resistance to are widely used in oral and injectable therapies used to treat a range of serious bacterial infections in clinical practice.

Diseases such as tuberculosis, colitis, and UTIs can be treated with some of the antibiotics that the researchers found resistance to, including rifampicin, vancomycin, and ciprofloxacin.

Part 1

Comment by Dr. Krishna Kumari Challa on February 17, 2026 at 11:30am

Yes, men have a biological clock too. But it's not just age that affects male fertility

Male fertility declines with age, with sperm count, motility, morphology, and semen volume decreasing from the early 20s, and genetic damage in sperm increasing, raising miscarriage and birth defect risks. Environmental and lifestyle factors, such as oxidative stress, toxins, smoking, obesity, and certain medical conditions, also impact male fertility. New guidelines recommend simultaneous fertility assessment for both partners.

https://theconversation.com/yes-men-have-a-biological-clock-too-but...

Comment by Dr. Krishna Kumari Challa on February 17, 2026 at 11:28am

Want a tall, smart child? How IVF tests are selling a dream

Genetic tests marketed to IVF parents claim to predict traits like height and intelligence using polygenic risk scores, but these predictions are highly uncertain and offer minimal benefit—typically only a few IQ points or centimeters in height. Environmental and lifestyle factors play a much larger role in child development, and using such tests poses ethical, psychological, and medical risks without proven advantages.

https://theconversation.com/want-a-tall-smart-child-how-ivf-tests-a...

Comment by Dr. Krishna Kumari Challa on February 17, 2026 at 11:17am

Injured birds seeking medical help

Injured seabird desperately pecks at hospital door for help

An injured seabird sought help by pecking at the door of an emergency room at a hospital in Germany until medical staff noticed it and called firefighters to help with its rescue.

The cormorant, a shiny black waterbird, had a triple fishing hook stuck in its beak when it made its presence known at the glass door of the Klinikum Links der Weser hospital in the northern city of Bremen on Sunday.

In a joint effort, medical staff and firefighters removed the fishhook and treated the wound, the Bremen firefighter department said in a statement. The bird was later released back into nature on the grounds of the hospital park.

"When an injured cormorant does approach humans, it is usually an animal in extreme distress that has lost its natural shyness," the statement said.

A cormorant is a large bird with a long neck, wedge-shaped head and a distinctive sharp beak with a hooked tip. A fishhook in the bird's beak would be extremely dangerous for the animal. Infections, pain and even starvation are possible, the firefighter department said.

Source: News agencies

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Comment by Dr. Krishna Kumari Challa on February 17, 2026 at 11:14am

Deep-sea fish larvae rewrite the rules of how eyes can be built

Deep-sea fish larvae possess unique hybrid photoreceptor cells that combine structural features of rods with the molecular machinery of cones, enabling enhanced vision in the dim twilight zone. Unlike the typical vertebrate pattern where cones precede rods, these larvae use rod-like cones early in development, with some species retaining them into adulthood. This challenges established models of vertebrate retinal development.

https://theconversation.com/deep-sea-fish-larvae-rewrite-the-rules-...

Comment by Dr. Krishna Kumari Challa on February 17, 2026 at 11:05am

Deer inhibit trees but raise plant diversity, 18-year study reveals

At high densities, white-tailed deer inhibit growth of trees but increase the overall diversity of smaller plant and weed species, according to a long-term study published recently.
High densities of white-tailed deer suppress tree regeneration and reduce tree presence in both above-ground vegetation and the soil seedbank, limiting natural forest regrowth. However, deer browsing increases the diversity and evenness of smaller plant and weed species by preventing dominance by a few species. Active management is likely required for successful reforestation in areas with abundant deer.

A. Sophie Westbrook et al, Deer impact seedbanks and plant communities over 18 years of post-agricultural succession, PLOS One (2025). DOI: 10.1371/journal.pone.0339466

Comment by Dr. Krishna Kumari Challa on February 17, 2026 at 10:25am

How one genome creates two distinct fungal bodies

Creatures that can change from one form to another ?

Yes,  Nature, too, has its shapeshifters, such as dimorphic fungi. While scientists have known for some time that they can reversibly transition between yeast and mycelium forms, a paper recently published in the journal Nature Communications explains how.

Some fungi, such as members of the Mucorales order, can live as yeasts, tiny single-celled organisms, or as mycelium, multicellular branching filaments. Triggers for the morphological switch include oxygen levels and glucose concentrations.  How can a single genome encode two different body plans and could switch between them?

To find out, scientists grew the fungus (Mucor lusitanicus) under oxygen-rich conditions to promote mycelial growth, and under low-oxygen, high-carbon-dioxide conditions to induce the yeast form. Once the fungus had changed shape, the team collected samples and examined the active genetic instructions, specifically the RNA, to see which were being used in each form.

The team found that instead of using the same genes for both forms, the fungus uses paralogs. These are closely related genes that share a common ancestor and arise when a gene is duplicated within a single genome.

In total, they found 490 dimorphic gene families. Although each twin pair has similar functions, there is a specific version for yeast and one for mycelium. For example, a gene responsible for iron absorption in the yeast form has a nearly identical counterpart that performs the same function in the mycelium form.

They are organized in a very elegant way in the genome. The scientists discovered that two related genes are positioned back to back on the DNA and share a bidirectional promoter. These regulate gene expression and so act like control switches. It means the promoters can easily turn one off and the other on without getting them mixed up.

At the heart of the operation, according to the researchers, are two master regulator genes, dkl and dfl. When the team deleted them, the fungus could no longer control its switches and lost its ability to change shape.

The findings identify an evolutionary mechanism that integrates and optimizes the genetic information required for two distinct life forms within a single organism.

One of the most exciting aspects of this research is the potential for new antifungal treatments. Knowing how a fungus switches to its invasive mycelial form gives scientists a clear target to stop the transformation and therefore the spread of fungal infections.

Ghizlane Tahiri et al, Coordinated gene family evolution shapes the genome of dimorphic Mucorales, Nature Communications (2026). DOI: 10.1038/s41467-026-68866-7

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