Ordnael
Emperor
I always try to find frogs to play with when I am holidaying at a river! Got some neat pictures and videos with a small frog sitting at my leg trying to catch passing flies!
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Newsworthy Science
- Thread starter Birdjaguar
- Start date
Adding a new layer to evolution.
These findings uncover a property of biological systems even deeper than the evolutionary processes that shape them. They reveal the landscape on which that shaping took place, and they show that it was only possible at all because the landscape has a very specific topology, in which functionally similar combinations of the component parts—genes, metabolites, protein or nucleic-acid sequences—are connected into vast webs that stretch throughout the whole of the multidimensional space, each intricately woven amidst countless others.
One might argue that the original creative act of the living world was the generation of the components themselves: the chemical ingredients, such as amino acids and sugars, that comprise the molecules of life. But this now seems like the easy part, the kind of happy accident that chemistry can supply given the right raw materials and environment. The harder question is how one can get beyond that passive soup to kick-start Darwinian evolution. Manrubia thinks that this primal creative step might itself be a consequence of the richness and intimate interweaving of neutral (or quasi-neutral) networks. This means that, even for random, abiotically generated RNA sequences, there is a significant chance of finding ones that perform some useful function. “In a sense, you have function for free if the phenotypes are sufficiently represented in sequence space,” she says. And her computer simulations show that such RNA sequences aren’t rare. “So sufficiently good solutions to act as seeds of the evolutionary process might arise in the absence of the evolutionary process itself.” In particular, there’s a fair chance of hitting on sequences that can replicate—and then you’re up and running. “Natural selection can very quickly turn mediocre solutions into fully adaptive ones,” Manrubia says.
nautil.us
These findings uncover a property of biological systems even deeper than the evolutionary processes that shape them. They reveal the landscape on which that shaping took place, and they show that it was only possible at all because the landscape has a very specific topology, in which functionally similar combinations of the component parts—genes, metabolites, protein or nucleic-acid sequences—are connected into vast webs that stretch throughout the whole of the multidimensional space, each intricately woven amidst countless others.
One might argue that the original creative act of the living world was the generation of the components themselves: the chemical ingredients, such as amino acids and sugars, that comprise the molecules of life. But this now seems like the easy part, the kind of happy accident that chemistry can supply given the right raw materials and environment. The harder question is how one can get beyond that passive soup to kick-start Darwinian evolution. Manrubia thinks that this primal creative step might itself be a consequence of the richness and intimate interweaving of neutral (or quasi-neutral) networks. This means that, even for random, abiotically generated RNA sequences, there is a significant chance of finding ones that perform some useful function. “In a sense, you have function for free if the phenotypes are sufficiently represented in sequence space,” she says. And her computer simulations show that such RNA sequences aren’t rare. “So sufficiently good solutions to act as seeds of the evolutionary process might arise in the absence of the evolutionary process itself.” In particular, there’s a fair chance of hitting on sequences that can replicate—and then you’re up and running. “Natural selection can very quickly turn mediocre solutions into fully adaptive ones,” Manrubia says.
The Strange Inevitability of Evolution
Good solutions to biology’s problems are astonishingly plentiful.
nautil.us
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Asians made humanity's longest prehistoric migration and shaped the genetic landscape in the Americas
Date:May 15, 2025Source:Nanyang Technological UniversitySummary:An international genomics study has revealed that early Asians undertook humanity's longest known prehistoric migration. These early humans, who roamed the earth over 100,000 years ago, are believed to have traveled more than 20,000 kilometers on foot from North Asia to the southernmost tip of South America. Scientists have mapped the unexpectedly vast genetic diversity of Asians, who make up more than half of the world's population. These findings overturn long-held assumptions of European genetic dominance and show that native South Americans are of Asian descent. The study also sheds light on how such a vast migration and differing environments have shaped human evolution, including how populations have adapted to diseases and how their immune systems have evolved.
Asians made humanity's longest prehistoric migration and shaped the genetic landscape in the Americas
An international genomics study has revealed that early Asians undertook humanity's longest known prehistoric migration. These early humans, who roamed the earth over 100,000 years ago, are believed to have traveled more than 20,000 kilometers on foot from North Asia to the southernmost tip of...
www.sciencedaily.com
PhroX
Deity
- Joined
- Jan 12, 2009
- Messages
- 2,801
At a glance, it seems like an interesting piece of work, but I'm really confused by this statement:
As, well, this isn't news. I'm pretty sure we've had clear genetic evidence that indigenous Americans are descended from Asian populations for quite some time now. And, frankly, even without genetics, it's kinda obvious, given that they got to American from Asia and have material culture and potentially linguistic connections to other Asian groups.
As far as I know, even things like the (now pretty conclusively disproven) Solutrean Hypothesis wasn't suggesting that European groups were the main ancestral population of the Americans, just that some prehistoric "Europeans" (in quotes as they only comprise a very small part of the ancestry of modern Europeans, who are primarily descended from groups that migrated into the continent later) had crossed the Atlantic and brought their material culture and some amount of interbreeding to the existing population.
As, well, this isn't news. I'm pretty sure we've had clear genetic evidence that indigenous Americans are descended from Asian populations for quite some time now. And, frankly, even without genetics, it's kinda obvious, given that they got to American from Asia and have material culture and potentially linguistic connections to other Asian groups.
As far as I know, even things like the (now pretty conclusively disproven) Solutrean Hypothesis wasn't suggesting that European groups were the main ancestral population of the Americans, just that some prehistoric "Europeans" (in quotes as they only comprise a very small part of the ancestry of modern Europeans, who are primarily descended from groups that migrated into the continent later) had crossed the Atlantic and brought their material culture and some amount of interbreeding to the existing population.
I think much of their point was not that they were of Asian descent, but that over the course of their travels and time, their genetics changed and became less robust.
"The study also sheds light on the evolutionary consequences of such a vast migration. Associate Professor Kim Hie Lim from NTU's Asian School of the Environment, the study's corresponding author, explained that the arduous journey over thousands of years had reduced the genetic diversity of the migrant population.
"Those migrants carried only a subset of the gene pool in their ancestral populations through their long journey. Thus, the reduced genetic diversity also caused a reduced diversity in immune-related genes, which can limit a population's flexibility to fight various infectious diseases," explained Assoc Prof Kim, a Principal Investigator at SCELSE and Vice-Director of GenomeAsia100K."
PhroX
Deity
- Joined
- Jan 12, 2009
- Messages
- 2,801
Yeah, that does indeed seem to be the focus of the work, which is why I said it was interesting. So why did the summary present the idea that Asians made a long migration into the Americas as news, and have nonsense like "long-held assumptions of European genetic dominance"? (Not criticising you here Birdjaguar, I'm complaining about the awful press release)
EnglishEdward
Deity
Yes, I too have noticed the generally increasing prevalence of discrepancies between A) headlines B) summaries and C) detailed content these days.
Since you are critiqueing the press release I shall point out that this is the work I described earlier.
Why Our Brains Crave Ideology
A neuroscientist reveals how to nurture authentic and flexible thinking
What makes ideology, as you write, the “brain’s delicious answer to the problem of prediction and communication?”
Our brains are these amazingly predictive organs trying to constantly explain the world, because that’s our way to survive. We have to have a reliable model of reality so that we can know what to expect—for example, when there’s going to be a confrontation with someone we’re in a relationship with. Ideologies give us the answers for all those predictions. We don’t have to do that job ourselves, because ideologies say, “Here’s how the world works, how social relationships work. Here are rules of conduct and thought.” We can rely on a compelling story and logical system that many other people are buying into, even if it’s wrong. Ideologies are incredibly seductive because they give us a community of people who we can belong to, and share information with. But that doesn’t mean they’re good for us. Because although that’s all very alluring, research suggests that ideologies can also be very injurious to our capacity for elastic, free, and authentic thought.
Have you studied the basis of cognitive flexibility in the brain?
In a large study that I ran with thousands of participants, we wanted to look at the genetics of rigidity, and what we homed in on was a neurotransmitter that we all know and love—dopamine. We know that dopamine governs our senses of reward, of pleasure, but it does that because it governs our learning. And there’s been a lot of research suggesting that our capacity to adapt is rooted in the functioning of dopamine. So we looked at whether people with genetic variations that affected how dopamine is distributed in their brain, whether those genes could predict people’s cognitive rigidity or flexibility. We found that they did. When people have less baseline dopamine in their prefrontal cortex, and a greater concentration of dopamine in their striatum, the midbrain area that governs learning and reward, that’s a particular genetic profile that puts people at risk for rigid thinking. We found that people with other combinations of these genes typically tended to be much more flexible.
Why Our Brains Crave Ideology
A neuroscientist reveals how to nurture authentic and flexible thinking
nautil.us
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Tea and beer concentrate forever chemicals
Trifluoroacetate (TFA) is an ultrashort-chain perfluoroalkyl substance, which is ubiquitously present in the aqueous environment. Due to its high mobility, it accumulates in plant material. The study presented here shows for the first time that TFA is a widely spread contaminant in beer and tea / herbal infusions.
In 104 beer samples from 23 countries, TFA was detected up to 51 µg/L with a median concentration of 6.1 µg/L. An indicative brewing test and a correlation approach with potassium (K) indicate that the main source of TFA in beer is most likely the applied malt. It could be proven that the impact of the applied water is negligible in terms of TFA, which was supported by the analysis of numerous tap water samples from different countries.
The unintended extraction of TFA was also demonstrated for tea / herbal infusions with a median concentration of 2.4 µg/L.
Trifluoroacetate (TFA) is an ultrashort-chain perfluoroalkyl substance, which is ubiquitously present in the aqueous environment. Due to its high mobility, it accumulates in plant material. The study presented here shows for the first time that TFA is a widely spread contaminant in beer and tea / herbal infusions.
In 104 beer samples from 23 countries, TFA was detected up to 51 µg/L with a median concentration of 6.1 µg/L. An indicative brewing test and a correlation approach with potassium (K) indicate that the main source of TFA in beer is most likely the applied malt. It could be proven that the impact of the applied water is negligible in terms of TFA, which was supported by the analysis of numerous tap water samples from different countries.
The unintended extraction of TFA was also demonstrated for tea / herbal infusions with a median concentration of 2.4 µg/L.
Ordnael
Emperor
[Sips from his cereal sized bowl of tea in the morning, shakes head and chooses to believe that CE compliant products are, somewhat, safer from forever chemicals]
Humpback Whales Blow Poloidal Vortex Bubble Rings
Fred Sharpe, Jodi Frediani, Josephine Hubbard, Doug Perrine, Simon Hilbourne, Joy S. Reidenberg, Laurance R. Doyle, Brenda McCowan
First published: 15 May 2025
Funding: This work was supported by the Templeton World Charity Foundation (TWCF0440).
Fred Sharpe and Jodi Frediani share first authorship.
Humpback whales (Megaptera novaeangliae) have long been known to generate bubbles by physically striking the air–water interface or releasing air through the blowholes or mouth. Melville (1851) was the first to note this propensity by penning “humpbacks churned the water … making more gay foam and whitewater than any of them.” In the Norwegian Sea, a whaleship observed a humpback whale that “appeared to dive a short distance below the water's surface and then release air while swimming in a circle. The rising bubble rose to the surface like a thick wall of air bubbles, and these formed a net” (Ingebrigtsen 1929). The first formal studies of humpback whale bubble use commenced in the North Pacific in the late 1960s (Jurasz and Jurasz 1979) followed by a description in the North Atlantic (Hain et al. 1982). Subsequent research across many cetacean species has shown that they produce bubbles in various shapes, sizes, and complexities. A recent review on bubble production (with a focus on odontocetes) classifies this wide diversity of bubble structures into several categories: trails, bursts, clouds, and rings (Moreno and Macgregor 2019).
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.
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Both playful and communicative overtures of bubble rings may hold deeper meaning (Graham et al. 2010) for humpback whales and their potential for interspecies communication (McCowan et al. 2023). As noted by Bearzi et al. (2018) concerning cetacean sentience and intentions, “we must acknowledge our present ignorance and keep a door open to the unexpected.”
Snowygerry
Deity
Prehistoric woman from Belgium gets a face and a name
Scientists and artists have presented a reconstruction of the face and living environment of a prehistoric woman who lived around 10,000 years ago...
www.belganewsagency.eu
Snowygerry
Deity
Proba-3’s first artificial solar eclipse
Today, the European Space Agency’s Proba-3 mission unveils its first images of the Sun’s outer atmosphere – the solar corona. The mission’s two satellites, able to fly as a single spacecraft thanks to a suite of onboard positioning technologies, have succeeded in creating their first ‘artificial...
www.esa.int
Overdoing Gender: A Test of the Masculine Overcompensation Thesis
The masculine overcompensation thesis asserts that men react to masculinity threats with extreme demonstrations of masculinity, a proposition tested here across four studies. In study 1, men and women were randomly given feedback suggesting they were either masculine or feminine. Women showed no effects when told they were masculine; however, men given feedback suggesting they were feminine ex- pressed more support for war, homophobic attitudes, and interest in purchasing an SUV. Study 2 found that threatened men expressed greater support for, and desire to advance in, dominance hierarchies. Study 3 showed in a large-scale survey on a diverse sample that men who reported that social changes threatened the status of men also reported more homophopic and prodominance attitudes, support for war, and belief in male superiority. Finally, study 4 found that higher testosterone men showed stronger reactions to masculinity threats than those lower in testosterone. Together, these results support the masculine overcompensation thesis, show how it can shape political and cultural attitudes, and identify a hormonal factor influencing the effect.
The masculine overcompensation thesis asserts that men react to masculinity threats with extreme demonstrations of masculinity, a proposition tested here across four studies. In study 1, men and women were randomly given feedback suggesting they were either masculine or feminine. Women showed no effects when told they were masculine; however, men given feedback suggesting they were feminine ex- pressed more support for war, homophobic attitudes, and interest in purchasing an SUV. Study 2 found that threatened men expressed greater support for, and desire to advance in, dominance hierarchies. Study 3 showed in a large-scale survey on a diverse sample that men who reported that social changes threatened the status of men also reported more homophopic and prodominance attitudes, support for war, and belief in male superiority. Finally, study 4 found that higher testosterone men showed stronger reactions to masculinity threats than those lower in testosterone. Together, these results support the masculine overcompensation thesis, show how it can shape political and cultural attitudes, and identify a hormonal factor influencing the effect.
Fairy wrens teach secret passwords to their unborn chicks to tell them apart from ****oo impostors
Not Exactly Rocket ScienceBy Ed Yong
Nov 8, 2012 4:00 PMNov 19, 2019 5:05 PM
[The banned word is Cu ckoo]
In Australia, a pair of superb fairy-wrens return to their nest with food for their newborn chick. As they arrive, the chick makes its begging call. It’s hard to see in the darkness of the domed nest, but the parents know that something isn’t right. Whatever’s in their nest, it’s not their chick. It doesn’t’ know the secret password. They abandon it, flying off to start a new nest and a new family somewhere else. It was a good call. The bird in their nest was a Horsfield’s bronze-****oo. These birds are “brood parasites” – they lay their eggs in those of other birds, passing on their parenting duties to some unwitting surrogates. The bronze-****oo egg looks very much like a fairy-wren egg, although it tends to hatch earlier. The ****oo chick then ejects its foster siblings from the nest, so it can monopolise its foster parents’ attention. But fairy-wrens have a way of telling their chicks apart from ****oos. Diane Colombelli-Negrel from Flinders University in Australia has shown that mothers sing a special tune to their eggs before they’ve hatched. This “incubation call” contains a special note that acts like a familial password. The embryonic chicks learn it, and when they hatch, they incorporate it into their begging calls. Horsfield’s bronze-****oos lay their eggs too late in the breeding cycle for their chicks to pick up the same notes. They can’t learn the password in time, and their identities can be rumbled.
This is one of many incredible adaptations in the long-running battle between birds and their brood parasite. As these evolutionary arms races continue, the parasites typically become ever better mimics, and the hosts typically become ever more discerning parents. This battle usually plays out before the eggs hatch. If the parents can recognise the parasitic eggs, they’ll eject or destroy them. If they can’t, they often end up feeding the parasite regardless of what it looks like. This is why the common ****oo has an egg that closely matches that of a reed warbler, but the ****oo chick is a huge, grey monster that looks completely unlike a warbler chick. But the fairy-wrens are different. In 2003, Naomi Langmore found that they will abandon 40 percent of nests that only have a Horsfield bronze-****oo chick in it, suggesting that they can indeed recognise these interlopers. Now, Colombelli-Negrel has discovered how they do it. She kept 15 nests under constant audio surveillance, and discovered that fairy-wrens call to their unhatched chicks, using a two-second trill with 19 separate elements to it. They call once every four minutes while sitting on their eggs, starting on the 9^th day of incubation and carrying on for a week until the eggs hatch. When Colombelli-Negrel recorded the chicks after they hatched, she heard that their begging call included a single unique note lifted from mum’s incubation call. This note varies a lot between different fairy-wren broods. It’s their version of a surname, a signature of identity that unites a family. The females even teach these calls to their partners, by using them in their own begging calls when the males return to the nest with food.
These signature calls aren’t innate. The chicks’ calls more precisely matched those of their mother if she sang more frequently while she was incubating. And when Colombelli-Negrel swapped some eggs between different clutches, she found that the chicks made signature calls that matches those of their foster parents rather than those of their biological ones. It’s something they learn while still in their eggs. This also explains why bronze-****oos don’t make the same calls. The female bronze-****oo tends to deposit her eggs while a fairy-wren’s clutch is around 12 days old. At this point, they’re just a couple of days away from hatching. “The ****oo embryo appears to have insufficient time to correctly learn the password note,” says Sonia Kleindorfer, who led the study. When they hatch, the fairy-wrens can tell that something isn’t right. They spend less time feeding their alien chick, more time making alarm calls, and more time scanning the surrounding area, possibly on the lookout for more ****oos. In many cases, they abandon the intruder to make a fresh start elsewhere.
This isn’t a clear win for the fairy-wrens. Colombelli-Negrel found very low levels of ****oo parasitism in her study, but Langmore previously showed that only 40 percent of the wrens abandon their ****oo-infested nests. “There appear to be cyclical fluctuations in ****oo prevalance in host nests across years,” says Kleindorfer. This might be because the local wrens become better or worse at recognising their signature notes, or the ****oos become better or worse at mimicking them. “Our study provides a testable framework to explain some of this variation.”
Reference: Colombelli-Negrel, Hauber, Robertson, Sulloway, Hoi, Griggio & Kleindorfer. 2012. Embryonic Learning of Vocal Passwords in Superb Fairy-Wrens Reveals Intruder ****oo Nestlings. Current Biology (2012), http://dx.doi.org/10.1016/j.cub.2012.09.025More on brood parasites:
https://www.discovermagazine.com/pl...icks-to-tell-them-apart-from-****oo-impostors
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Broken_Erika
Play with me.
UNB researchers find 33-year-old puffin, marking a known record age for the bird
Researchers searched burrows on Machias Seal Island at night to find the old puffin
How old is an old puffin?Well, the oldest known puffin in New Brunswick — and Canada — was found this week at 33 years old.
Researchers at the Atlantic Laboratory for Avian Research, through the University of New Brunswick, located the puffin born in 1992 on Machias Seal Island, located in the Gulf of Maine, with its original identification bands from over three decades ago.
Daniel Oliker, a graduate student at the University of New Brunswick studying Atlantic puffin ecology, says he's confident saying this is the oldest puffin ever recaptured in the province — its first capture was when it was banded — and it's among the oldest across North America.
"It's pretty significant and it's a unique piece of information to gather," Oliker said.
Records indicate the previous oldest was 29 years old, "so this one beats our record by four years which is pretty substantial."
The research team has been monitoring puffins and five other species of seabirds, including razorbills, common murres and Leach's storm petrels, on Machias Seal Island since 1995.
Before that, Canada Wildlife Services had staff who lived on the island to oversee tourist landings, observe birds on the island and band puffin chicks.
While researchers today use two metal bands as identification markers, plastic bands were used for a couple of years after the research program began.
When a researcher spotted a puffin wearing a plastic band earlier this week, Oliker said, the team knew it must be very old.
They waited until dark, when puffins are more likely to be in their burrows, and then went searching.
"We grubbed a bunch of burrows," Oliker said. "That just means sticking your hand in the burrow and looking for the bird. And then I felt something that didn't feel like a metal band on a bird's leg, but a plastic one … so I pulled it out.
"Lo and behold, it was a plastic one, and this band was really cool because it was extremely worn out, the most worn-out band I've ever seen."
Oliker said numbers on the band were still legible, and it was determined this puffin was last seen in 2007.
"Just being able to find that bird, kind of getting lucky getting to the right burrow and actually making out what the band number said was a bit of luck," he said.
"It was very exciting, it's always fun to get those old birds and see their history."
Tony Diamond, who started the Machias Seal Island research program 30 years ago and so, said this find shows how driven that group of researchers is, because of how difficult that identification band would have been to read.
He said this find alone just expanded the length of this research project in entirety by several years, so it's significant.
"It's not just a measure of how long the puffins live, it's a measure of how long that research has been going," Diamond said.
"It's very exciting that they caught that bird, and it speaks highly of their motivation."
Oliker said the puffin now sports a new metal band, so researchers on the island can continue monitoring it for years to come.
He said this kind of information is important to understand the longevity and lifespan of puffins, how many chicks they can rear in their lifetime, and how they've fared through environmental changes.
"Being born in 1992, [this puffin] has gone through a lot in its lifetime, especially in the last 20 years or so, with the sort of drastic changes in the environment," Oliker said.
"It's still able to raise chicks and hopefully raise successful chicks, and it's still alive. So it tells us a lot about how hardy and persistent these birds are."
https://www.cbc.ca/news/canada/new-...antic-laboratory-avian-research-unb-1.7581915
Ordnael
Emperor
Was I the only one that at first glance read "...find 33 year old muffin..."?
Sex at birth is not always random — mum’s age and genetics can play a part
Writeup Paper
In families with several children of the same sex, the odds of having another baby of that sex are higher than of having one of the opposite sex, according to a large study1 that investigated the maternal and genetic factors that influence the sex of offspring.
The results, published in Science Advances today, find that in families with three boys, there is a 61% chance that the next sibling is male. For families with three girls, there was a 58% chance that the next child would be female.
The findings challenge what people have been told about their baby’s sex, which is that for each pregnancy, there is an equal chance of having either a boy or a girl, says Alex Polyakov, an obstetrician and researcher at the University of Melbourne, Australia. “Based on these findings, you have to tell couples that their chance of having a different-sex child from what they already have is actually less than 50:50,” he says.
Age influences sex
Researchers at Harvard University in Boston, Massachusetts, looked at the sex of children born to 58,007 female nurses in the United States between 1956 and 2015, and the different factors that might explain why some had only boys and others only girls.
They found that in two-child families, having one child of each sex was more common than two boys or two girls, but in families with three or more children, siblings of the same sex were more common than a mix of both. In their analysis, the researchers excluded the last birth of each woman to reduce the influence of parental choice — for instance, some people choose to stop having children once they have both boys and girls.
The team also found that women aged 29 or older when they had their first child had a 13% higher chance of giving birth to only male or only female children than were women younger than 23.
The authors note that changes in vaginal pH as women age could explain this phenomenon. For instance, the changes could influence the sex of the child by affecting whether sperm carrying the X chromosome or the Y chromosome are more successful at fertilizing the egg, says Polyakov.
Genetic influence
A genomic analysis also showed that some women had one of two common genetic variants that were associated with having children of a particular sex. A change in chromosome 10, in a gene called NSUN6, was associated with a higher probability of having only girls, while women with a change in a single DNA letter on chromosome 18, near a gene called TSHZ1, were more likely to have only boys.
Writeup Paper
In families with several children of the same sex, the odds of having another baby of that sex are higher than of having one of the opposite sex, according to a large study1 that investigated the maternal and genetic factors that influence the sex of offspring.
The results, published in Science Advances today, find that in families with three boys, there is a 61% chance that the next sibling is male. For families with three girls, there was a 58% chance that the next child would be female.
The findings challenge what people have been told about their baby’s sex, which is that for each pregnancy, there is an equal chance of having either a boy or a girl, says Alex Polyakov, an obstetrician and researcher at the University of Melbourne, Australia. “Based on these findings, you have to tell couples that their chance of having a different-sex child from what they already have is actually less than 50:50,” he says.
Age influences sex
Researchers at Harvard University in Boston, Massachusetts, looked at the sex of children born to 58,007 female nurses in the United States between 1956 and 2015, and the different factors that might explain why some had only boys and others only girls.
They found that in two-child families, having one child of each sex was more common than two boys or two girls, but in families with three or more children, siblings of the same sex were more common than a mix of both. In their analysis, the researchers excluded the last birth of each woman to reduce the influence of parental choice — for instance, some people choose to stop having children once they have both boys and girls.
The team also found that women aged 29 or older when they had their first child had a 13% higher chance of giving birth to only male or only female children than were women younger than 23.
The authors note that changes in vaginal pH as women age could explain this phenomenon. For instance, the changes could influence the sex of the child by affecting whether sperm carrying the X chromosome or the Y chromosome are more successful at fertilizing the egg, says Polyakov.
Genetic influence
A genomic analysis also showed that some women had one of two common genetic variants that were associated with having children of a particular sex. A change in chromosome 10, in a gene called NSUN6, was associated with a higher probability of having only girls, while women with a change in a single DNA letter on chromosome 18, near a gene called TSHZ1, were more likely to have only boys.
Spoiler Analysis of many factors - Being an evening type person makes you more likely to have all the same sex childre? :
Look at this autocensor nonsense @ThunderfallFairy wrens teach secret passwords to their unborn chicks to tell them apart from cu.ckoo impostors
Not Exactly Rocket Science
By Ed Yong
Nov 8, 2012 4:00 PMNov 19, 2019 5:05 PM
[The banned word is Cu ckoo]
In Australia, a pair of superb fairy-wrens return to their nest with food for their newborn chick. As they arrive, the chick makes its begging call. It’s hard to see in the darkness of the domed nest, but the parents know that something isn’t right. Whatever’s in their nest, it’s not their chick. It doesn’t’ know the secret password. They abandon it, flying off to start a new nest and a new family somewhere else. It was a good call. The bird in their nest was a Horsfield’s bronze-****oo. These birds are “brood parasites” – they lay their eggs in those of other birds, passing on their parenting duties to some unwitting surrogates. The bronze-****oo egg looks very much like a fairy-wren egg, although it tends to hatch earlier. The ****oo chick then ejects its foster siblings from the nest, so it can monopolise its foster parents’ attention. But fairy-wrens have a way of telling their chicks apart from ****oos. Diane Colombelli-Negrel from Flinders University in Australia has shown that mothers sing a special tune to their eggs before they’ve hatched. This “incubation call” contains a special note that acts like a familial password. The embryonic chicks learn it, and when they hatch, they incorporate it into their begging calls. Horsfield’s bronze-****oos lay their eggs too late in the breeding cycle for their chicks to pick up the same notes. They can’t learn the password in time, and their identities can be rumbled.
This is one of many incredible adaptations in the long-running battle between birds and their brood parasite. As these evolutionary arms races continue, the parasites typically become ever better mimics, and the hosts typically become ever more discerning parents. This battle usually plays out before the eggs hatch. If the parents can recognise the parasitic eggs, they’ll eject or destroy them. If they can’t, they often end up feeding the parasite regardless of what it looks like. This is why the common ****oo has an egg that closely matches that of a reed warbler, but the ****oo chick is a huge, grey monster that looks completely unlike a warbler chick. But the fairy-wrens are different. In 2003, Naomi Langmore found that they will abandon 40 percent of nests that only have a Horsfield bronze-****oo chick in it, suggesting that they can indeed recognise these interlopers. Now, Colombelli-Negrel has discovered how they do it. She kept 15 nests under constant audio surveillance, and discovered that fairy-wrens call to their unhatched chicks, using a two-second trill with 19 separate elements to it. They call once every four minutes while sitting on their eggs, starting on the 9^th day of incubation and carrying on for a week until the eggs hatch. When Colombelli-Negrel recorded the chicks after they hatched, she heard that their begging call included a single unique note lifted from mum’s incubation call. This note varies a lot between different fairy-wren broods. It’s their version of a surname, a signature of identity that unites a family. The females even teach these calls to their partners, by using them in their own begging calls when the males return to the nest with food.
These signature calls aren’t innate. The chicks’ calls more precisely matched those of their mother if she sang more frequently while she was incubating. And when Colombelli-Negrel swapped some eggs between different clutches, she found that the chicks made signature calls that matches those of their foster parents rather than those of their biological ones. It’s something they learn while still in their eggs. This also explains why bronze-****oos don’t make the same calls. The female bronze-****oo tends to deposit her eggs while a fairy-wren’s clutch is around 12 days old. At this point, they’re just a couple of days away from hatching. “The ****oo embryo appears to have insufficient time to correctly learn the password note,” says Sonia Kleindorfer, who led the study. When they hatch, the fairy-wrens can tell that something isn’t right. They spend less time feeding their alien chick, more time making alarm calls, and more time scanning the surrounding area, possibly on the lookout for more ****oos. In many cases, they abandon the intruder to make a fresh start elsewhere.
This isn’t a clear win for the fairy-wrens. Colombelli-Negrel found very low levels of ****oo parasitism in her study, but Langmore previously showed that only 40 percent of the wrens abandon their ****oo-infested nests. “There appear to be cyclical fluctuations in ****oo prevalance in host nests across years,” says Kleindorfer. This might be because the local wrens become better or worse at recognising their signature notes, or the ****oos become better or worse at mimicking them. “Our study provides a testable framework to explain some of this variation.”
Reference: Colombelli-Negrel, Hauber, Robertson, Sulloway, Hoi, Griggio & Kleindorfer. 2012. Embryonic Learning of Vocal Passwords in Superb Fairy-Wrens Reveals Intruder ****oo Nestlings. Current Biology (2012), http://dx.doi.org/10.1016/j.cub.2012.09.025More on brood parasites:
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