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Comment by Dr. Krishna Kumari Challa on December 14, 2025 at 10:20am

Is The Y Chromosome Vanishing?

The Y chromosome has long been rumored to be vanishing. So what does that mean for the future of men?
Some evolutionary biologists  say what’s in store for the human species.

They think the Y chromosome is running out of time.
Already, it’s lost 97 percent of its ancestral genes in the last 300 million years.

At that rate, it could disappear in another 6 million years, and a new sex gene may take its place.

Still, not everyone agrees that the Y chromosome is doomed. A potent scientific debate is brewing.

https://www.sciencealert.com/is-the-y-chromosome-vanishing-a-new-se...

Comment by Dr. Krishna Kumari Challa on December 14, 2025 at 10:14am

Fake participants and bots threaten quality of online research data
Online qualitative research faces risks from fraudulent participants, including bots and ineligible humans, which can compromise data quality. Identifying and removing such responses is challenging but essential. Strategies to mitigate these risks include careful recruitment planning, screener surveys, and community-engaged methods to enhance data integrity.

Devon Ziminski et al, Preventing and mitigating fraudulent research participants in online qualitative violence and injury prevention research, BMJ Open Quality (2025). DOI: 10.1136/bmjoq-2025-003706

Comment by Dr. Krishna Kumari Challa on December 14, 2025 at 10:08am

While maternal diet and breast milk antibodies are central to the new paper, the researchers emphasize that the "farm effect" is almost certainly multifactorial and can vary between individuals.

Courtney M. Jackson et al, Farm exposure in infancy is associated with elevated systemic IgG₄, mucosal IgA responses, and lower incidence of food allergy, Science Translational Medicine (2025). DOI: 10.1126/scitranslmed.ads1892

Part 2

Comment by Dr. Krishna Kumari Challa on December 14, 2025 at 10:06am

Farm-living families develop earlier immune maturation against food allergies, study finds

Children who grow up in farming communities have long been known to develop far fewer allergies than their urban peers. A new study offers one possible reason why: their immune systems may mature faster, and breast milk appears to play an important supporting role.

What this study shows is that their B cell and antibody responses are essentially ahead of schedule compared to urban infants. Their immune systems seem better equipped, earlier in life, to handle foods and other exposures without overreacting.

Farm-exposed infants had more memory and IgG+ B cells, suggesting earlier maturation of the antibody-producing system. They also had higher levels of IgG and IgA antibodies in blood, saliva, and stool, and higher IgA levels in human milk from their mothers. Taken together, the data point to a more robust and active antibody system in infants growing up in a traditional farming lifestyle.

Researchers saw a continuum: the more egg-specific antibodies in breast milk, the less likely babies were to develop egg allergy.

The  data suggest there may be particular benefit when mothers have high levels of food-specific antibodies in their milk. Not every mother does, and that could help explain why results have been mixed on the association between breastfeeding and food allergy.

Why do Mennonite mothers have more egg-specific antibodies? One likely factor is diet. Old Order Mennonite families typically raise their own chickens and eat eggs frequently. That repeated exposure appears to boost mothers' antibody levels against egg proteins, which then show up both in the bloodstream and in breast milk.

Just as an infection or a vaccine can boost your antibody levels, regularly eating certain foods could do the same.

The study also found differences in antibodies to other environmental allergens at birth. OOM infants were born with higher cord blood levels of IgG and IgG4 antibodies to dust mites and horse, reflecting their mothers' exposures, while urban infants had higher antibodies to peanut and cat. The team detected several food antigens in cord blood, and even antigen-specific IgA at birth, suggesting that in-utero exposure to food proteins may also shape early immunity.

Part 1

Comment by Dr. Krishna Kumari Challa on December 14, 2025 at 9:56am

Lab-developed mosquitoes prevent malaria parasite development, paving way for future field trials

In a new study published in Nature, scientists have successfully developed genetically modified mosquitoes in Tanzania that block the transmission of malaria.

In 2023, Transmission Zero's leading researchers created the first transgenic mosquito strain ever developed in Africa, in Tanzania. Its latest research offers a new solution by genetically modifying Anopheles gambiae mosquitoes (malaria-carrying mosquitoes) to block the development of malaria parasites, effectively reducing their ability to transmit the disease.
This approach allows these precise changes in the mosquitoes' ability to carry the malaria parasite to be passed down from one mosquito generation to the next.

These findings on Anopheles gambiae are the pathfinder for the technology to be extended to other equally important malaria vectors such as Anopheles arabiensis and Anopheles funestus, as well as vectors of diseases such as dengue and chikungunya.

Conducted entirely under containment, the study introduced antimalarial traits—naturally occurring molecules from frogs and honeybees—into local mosquito populations. The modified mosquitoes effectively prevented Plasmodium falciparum, the primary malaria parasite in Africa, from developing, creating a significant barrier to transmission.

While the results are promising, further research is required before field trials can begin.

Tibebu Habtewold et al, Gene-drive-capable mosquitoes suppress patient-derived malaria in Tanzania, Nature (2025). DOI: 10.1038/s41586-025-09685-6

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Comment by Dr. Krishna Kumari Challa on December 14, 2025 at 9:47am

Scientists teach helices to switch shapes
Synthetic molecules can be programmed to form specific helical structures by embedding instructions in their sequence, enabling control over helix type and the ability to switch shapes in response to environmental changes. These helices possess internal cavities capable of trapping persistent pollutants like perfluorinated sulfonates, indicating potential for adaptive materials and environmental applications.

Dimitri Delcourt et al, Programmable Assembly of Multistranded Helices in Water, Nature Communications (2025). DOI: 10.1038/s41467-025-67227-0

Comment by Dr. Krishna Kumari Challa on December 14, 2025 at 9:42am

When birds of two different species mate, their hybrid offspring inherit genes from both parents. When that hybrid goes on to mate with an individual of one of its parent species, it can pass on genes from the other. Over several generations, the genetic material from one species can be incorporated into the other, which is called introgression.

The  research group previously identified introgression of a gene called BCO2 among several species of wood warblers within the genus Setophaga, but it seemed like the version of the gene that was getting passed around might have originated from outside that group. Here, they confirmed that this version of the gene came from outside the genus and found that it has been exchanged between species of a different genus on multiple occasions.

The gene beta-carotene oxygenase 2 (BCO2), when turned on, produces a protein that breaks down yellow carotenoids, resulting in more white or gray coloration. When turned off, BCO2 results in the accumulation of yellow carotenoids and thus yellow plumage.

The researchers found evidence of introgression of BCO2 among several wood warbler species, including from a species within the genus Leiothlypis to multiple Setophaga species as well as to multiple species in the genus Cardellina. They also observed introgression of BCO2 from the genus Vermivora to Geothlypis, though the order and exact timing of these exchanges remain unclear.

Scientists think the initial introgression events from Leiothlypis occurred between half a million to two million years ago—while the donor and recipient species themselves diverged several million years before that.

But the 'borrowed' version of this gene has stuck around all that time, even as the species themselves evolved and split.

While introgression of BCO2 from Leiothlypis to other species may have occurred millions of years ago, the researchers suggested that introgression into one species, the red-faced warbler, is not only more recent, but is currently in progress, as not all members of the species they sampled contained the borrowed version of the gene.

A colorful legacy of hybridization in wood-warblers includes frequent sharing of carotenoid genes among species and genera, PLOS Biology (2025). DOI: 10.1371/journal.pbio.3003501

Part 2

Comment by Dr. Krishna Kumari Challa on December 14, 2025 at 9:36am

Warblers borrow color-related genes from evolutionary neighbours, study finds

Wood warblers, also called New World warblers, are some of the most colorful birds in North America, with more than a hundred species in the family ranging in color from yellow, orange and red to blue, green and pink. A new study led by researchers at Penn State has uncovered several instances of the birds passing color-related genes to other species of wood warblers, including those that are not closely related.

This glimpse into the hidden evolutionary dynamics of these songbirds may help explain why some species display certain colors as well as how the group diversified into so many different species in such a relatively short evolutionary time, the researchers said.

A paper describing the research appeared Dec. 11 in the journal PLOS Biology.

It turns out that some of these birds may have borrowed colors from their neighbors, rather than evolving them independently. Scientists previously found evidence that a particular color-related gene had been shared between species within the same genus, which is one notch up on the taxonomic ladder, but now they show that there is gene movement from species in one genus to another. That means some genetic funny business was going on with these warblers millions of years ago.

In addition to the pigment melanin, which produces brown and black plumage, the colors of wood warblers are influenced by carotenoid pigments, which are responsible for bright yellow, red and orange plumage. The research team collected DNA from 400 warblers across 100 species and six subspecies, focusing on three main genes related to carotenoid pigments.

The team compared an evolutionary tree of the warblers—built using their entire genomes and representing the overall relationships among the birds—with trees they created independently for each of the three carotenoid-related genes. These gene-specific trees show similarities and differences of the individual gene across the family, and discrepancies between the trees suggest where gene exchanges may have occurred. Statistical follow-up tests confirmed the gene exchanges, which the researchers said resulted from a process called introgression.

Part 1

Comment by Dr. Krishna Kumari Challa on December 14, 2025 at 9:30am

To reach their conclusion, the researchers considered both possibilities for the lack of X-ray sources in small galaxies in their large Chandra sample. The amount of gas falling onto a black hole determines how bright or faint they are in X-rays. Because smaller black holes are expected to pull in less gas than larger black holes, they should be fainter in X-rays and often not detectable. The researchers confirmed this expectation.

However, they found that an additional deficit of X-ray sources is seen in less massive galaxies beyond the expected decline from decreases in the amount of gas falling inwards. This additional deficit can be accounted for if many of the low-mass galaxies simply don't have any black holes at their centers. The team's conclusion was that the drop in X-ray detections in lower mass galaxies reflects a true decrease in the number of black holes located in these galaxies.
This result could have important implications for understanding how supermassive black holes form. There are two main ideas: In the first, a giant gas cloud directly collapses into a black hole, which contains thousands of times the sun's mass from the start. The other idea is that supermassive black holes instead come from much smaller black holes, created when massive stars collapse.
The formation of big black holes is expected to be rarer, in the sense that it occurs preferentially in the most massive galaxies being formed, so that would explain why we don't find black holes in all the smaller galaxies, say the researchers.

Fan Zou et al, Central Massive Black Holes Are Not Ubiquitous in Local Low-mass Galaxies, The Astrophysical Journal (2025). DOI: 10.3847/1538-4357/ae06a1

Part 2

Comment by Dr. Krishna Kumari Challa on December 14, 2025 at 9:27am

Small galaxies may buck the black hole trend, Chandra finds

Most smaller galaxies may not have supermassive black holes in their centers, according to a recent study using NASA's Chandra X-ray Observatory. This contrasts with the common idea that nearly every galaxy has one of these giant black holes within their cores, as NASA leads the world in exploring the secrets of how the universe works.

A team of astronomers used data from more than 1600 galaxies collected in more than two decades of the Chandra mission. The researchers looked at galaxies ranging in heft from over ten times the mass of the Milky Way down to dwarf galaxies, which have stellar masses less than a few percent of that of our home galaxy. A paper describing these results has been published in The Astrophysical Journal.

The team has reported that only about 30% of dwarf galaxies likely contain supermassive black holes.

As material falls onto black holes, it is heated by friction and produces X-rays. Many of the massive galaxies in the study contain bright X-ray sources in their centers, a clear signature of supermassive black holes in their centers. The team concluded that more than 90% of massive galaxies—including those with the mass of the Milky Way—contain supermassive black holes.
However, smaller galaxies in the study usually did not have these unambiguous black hole signals. Galaxies with masses less than three billion suns—about the mass of the Large Magellanic Cloud, a close neighbor to the Milky Way—usually do not contain bright X-ray sources in their centers.

The researchers considered two possible explanations for this lack of X-ray sources. The first is that the fraction of galaxies containing massive black holes is much lower for these less massive galaxies. The second is the amount of X-rays produced by matter falling onto these black holes is so faint that Chandra cannot detect it.

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