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For The First Time, An External Factor Turns A Male Mammal Into A Female

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All living people have been both male and female at the same time for six weeks. Although our sex is determined at the moment the sperm fertilizes the egg, it is not until a month and a half later that the biological programming to develop testes or ovaries is activated.

Textbooks have always taught that this process is 100% dictated by genetics: males have one female and one male chromosome, XY, and females have two female chromosomes, XX. But on Wednesday, the results of a bold experiment with mice were published, showing that very low iron levels in the mother can transform males into females, regardless of their genetics.

“To our knowledge, this is the first demonstration that an environmental factor can influence sex determination in a mammal,” Makoto Tachibana, a biologist at Osaka University in Japan and leader of the research, published in the journal Nature, tells EL PAÍS. “The most important implication of this finding,” he adds, “is that environmental and metabolic conditions influence fundamental developmental decisions that until now were thought to be strictly determined by genetics.”

Almost four decades ago, the study of people born with ovaries despite being genetically male (XY), and vice versa — a rare genetic disorder — led to the discovery of the SRY gene. This genetic fragment within the male Y chromosome is the main factor responsible for sexual differentiation in mammals. If the gene is present, the gonads begin to form testes at six weeks of development; if not, they inevitably become ovaries.

This process also initiates the production of sex hormones and the activation of other genes that produce more physical traits characteristic of each sex. All this happens in the highly protected environment of the uterus, safe from environmental interference. Mammals are unusual in this respect, since many animals determine their sex based on temperature, social hierarchy, size, or parasites infecting the mother, as occurs in some reptiles, fish, and insects.

The researchers discovered that if iron concentration is reduced by 60% at the cellular level, the testicular gene is switched off. When they reproduced this iron deficiency in pregnant female mice carrying males, they observed that six out of 39 XY offspring were born with two ovaries, a complete sex reversal. Another mouse was born intersex, with one ovary and one testicle.

The same happened in another set of experiments, where they studied the morphology of embryos from mothers treated with a drug that sequesters iron from the body: five out of 72 males developed female sexual organs. Although these numbers of sex reversal might seem small, it is an undeniable effect on a fundamental developmental mechanism previously thought to be shielded from the outside.

The study details how an external factor ends up influencing the fetus’s genetics. It is through epigenetics, a collection of chemical marks sensitive to environmental factors located on the genome that modify its functioning.

Extremely low iron affects the enzyme KDM3A, which modifies a chemical change that turns off the testis-producing gene SRY right at the moment of sex determination. The result is genetically male mice with two ovaries that lived apparently healthy up to eight weeks, although it has not been studied whether they could reproduce — in humans, sex reversal usually leads to infertility.

Iron deficiency in the body, which can cause anemia, is a health risk for both the mother and the baby. This deficiency is usually not severe and can be corrected on its own or by eating iron-rich foods such as cockles. However, in more severe cases, it must be treated, as it can increase the risk of miscarriage, perinatal mortality, and susceptibility to infections in the baby.

Makoto Tachibana

“At this point, we don’t know if a similar process could occur in humans,” says Tachibana. While he believes it would be difficult to find such low iron levels in nature, he argues “it’s a very important question that deserves to be investigated.”

Francisco Javier Barrionuevo, professor of genetics at the University of Granada in Spain, who did not participate in the study, highlights its importance. “Discovering that something as mundane as iron concentration can cause a mammalian embryo to develop as a female is spectacular,” he explains.

His team is investigating several biological components that can interfere in this process, including one they discovered very recently: tiny RNA sequences with no apparent function that are nevertheless capable of causing a complete sex reversal. In this case, the biologist warns, it is even more surprising because it is an external element not linked to the genetic code. Barrionuevo returns to the question raised by his Japanese colleague.

“Something like this has never been described in humans, as the study itself explains, but I think it could have happened in cases of extreme malnutrition and simply gone undetected,” he adds.

In an op-ed published alongside the study, cellular biologists Shannon Dupont and Blanche Capel, from Duke University in the United States, celebrate the “impressive series of experiments.” This study “provides clear evidence that variations in metabolism in the controlled uterine environment interface with the genetic sex-determination cascade and affect testis development,” state the researchers.

Chapel and Dupont note that iron deficiency is a known factor that can affect the health of both the mother and the baby, potentially impacting their neurological development. Following this line of thought, they wonder what other more subtle effects this deficiency might have, which opens up the possibility that the mother’s diet could affect not only the formation of testes but also other traits of “masculinity.”

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America

A Democratic Lawmaker Was Shot And Killed In Minnesota, Another Was Wounded In An Attack At Their Homes

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Two Minnesota state lawmakers were shot Saturday at their homes in Champlin and Brooklyn Park, north of Minneapolis, authorities said. State Senator John Hoffman was wounded, and State Representative Melissa Hortman was killed along with her husband. Hoffman’s wife was also wounded. Both represent districts north of Minneapolis. Minnesota Governor Tim Walz considers it a targeted act of “political violence.” “Peaceful discourse is the foundation of our democracy. We don’t settle our differences with violence or at gunpoint,” he said.

Hortman was the top Democratic leader in the state legislature and former speaker of the Minnesota House of Representatives. She was first elected in 2004. She was a lawyer and had two children. Hoffman, also a Democrat, was first elected in 2012. He runs Hoffman Strategic Advisors, a consulting firm. Previously, he was vice chair of the Anoka Hennepin School Board, which oversees Minnesota’s largest school district. Hoffman is married and has one daughter.

Drew Evans, superintendent of the Bureau of Criminal Apprehension, said authorities are searching for the suspect, who was wearing a law enforcement uniform. The suspect fired at officers who arrived at the home of one of the lawmakers. A manifesto and a list of dozens of targets —including the congresspeople shot this Saturday, other lawmakers, and pro-abortion activists — were found in his vehicle.

“Suspect exploited the trust of our uniforms, what our uniforms are meant to represent. That betrayal is deeply disturbing to those of us who wear the badge with honor and responsibility,” Public Safety Commissioner Bob Jacobson said. Authorities are working to determine the motive behind the attacks but are still in the early stages of the investigation.

The Brooklyn Park City Council asked residents to stay in their homes within a three-mile radius around a local golf course while the search continues for the suspect, who is considered “armed and dangerous,” according to a post on its Facebook page. “Suspect is white male, brown hair, wearing black body armor over blue shirt and blue pants and may misrepresent himself as law enforcement. Do not approach,“ it warned.

Authorities have asked Minnesota residents to avoid the protests against U.S. President Donald Trump, scheduled for this Saturday under the slogan No Kings, coinciding with the first military parade in Washington since 1991. Their message includes a photograph of flyers bearing that slogan on the seat of a car, apparently the suspect’s vehicle. The organization canceled the protests in Minnesota following the authorities’ recommendation.

The pretext for the parade is the 250th anniversary of the Army, but it coincides with Trump’s 79th birthday. He has been fixated on holding a military parade since his first term and has taken advantage of the timing amid criticism from the Democratic opposition. The parade also comes as Trump has deployed the military to suppress protests in Los Angeles against his immigration policy.

Melissa Hortman and John Hoffman, both lawmakers and members of the Democratic Party in Minnesota.

“We are here today because an unspeakable tragedy has unfolded in Minnesota. My good friend, a new colleague, Speaker Melissa Hortman, and her husband Mark, were shot and killed just this morning in what appears to be a politically motivated assassination,” Walz said at a news conference. “Our state has lost a great leader, and I have lost a dearest of friends. Speaker Hortman was someone who served the people of Minnesota with grace, compassion, humor, and a sense of service. She was a formidable public servant, a fixture, and a giant in Minnesota. She woke up every day determined to make this state a better place. She is irreplaceable,” he added.

“My prayers also go out to State Senator John Hoffman and his wife, who were shot multiple times. The Hoffmans have come out of surgery and are receiving care, and we are cautiously optimistic that they will survive this assassination attempt,” the governor said.

“We must all, in Minnesota and across the country, stand against all forms of political violence,” Walz insisted. “This tragic act here in Minnesota should serve as a reminder to all of us that democracy and the debates in the halls of Congress, in state houses, in school boards, is a way to settle our differences peacefully and move society to a better place,” he added.

Trump, who was the target of two assassination attempts last year, addressed the attacks through Truth, his social media platform. “I have been briefed on the terrible shooting that took place in Minnesota, which appears to be a targeted attack against State Lawmakers. Our Attorney General, Pam Bondi, and the FBI, are investigating the situation, and they will be prosecuting anyone involved to the fullest extent of the law. Such horrific violence will not be tolerated in the United States of America,” he wrote.

“This morning Minnesota woke up to news of a brutal act of violence targeting public servants. I am heartbroken to learn that our Speaker Melissa Hortman, Sen. John Hoffman and their spouses have been shot. I’ve worked closely with these fine legislators for many years. Archie and I are grateful for the incredible response of law enforcement and hope that everyone will be safe today,” tweeted State Senator Tina Smith.

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El Cairo

One-Dollar Rents Have Their Days Numbered In Egypt

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In recent years, entering the rental market in Egypt has become a nightmare. Since the beginning of 2021, the local currency has fallen by 70% against the dollar, while the inflation rate has reached historic highs of 40%. The market has become an incoherent and ever-changing jungle, where no one quite knows how to set prices, or for how long.

As if the situation weren’t unstable enough, the Supreme Constitutional Court dropped another bombshell in November of 2024, by striking down the core of a law that kept old rents frozen for decades, while allowing leases to be inherited. Although the legal battle dates back 37 years, the judges have only given the Parliament of Egypt until the end of June to amend it. Otherwise, those rent caps will be removed.

Egyptian rental contracts were deregulated by a 1996 law that created a dual system between contracts signed prior to that year and those signed since then, the latter of which are subject to market prices. According to the latest census, conducted in 2017, only 14% of families in the country live in rented accommodation. At face value, renting doesn’t seem like a very popular option. The problem — as is often the case in Egypt — is the absolute numbers hidden behind the percentages. In this case, 3.3 million families — including 1.6 million with old contracts — and the plurality (1.1 million of them) are concentrated in the Cairo metropolitan area, where this type of contract covers 25% of all households.

One of the main complaints from landlords is that, over time, the price difference between old and new rentals has become absurd. This is especially the case in the capital, where some 600,000 households are paying rents of less than 50 Egyptian pounds a month (about $1) and, in the most expensive cases, barely 900 pounds ($18). Although there’s a wide variation, the price of new rentals can easily be up to 100 times higher. This situation has left many buildings in a deplorable condition, because landlords are unwilling — or unable — to maintain them properly. It has also led some landlords to choose to leave their apartments empty for decades. And, in the most extreme cases, they have resorted to vandalism, so as to empty apartments or vacate buildings and then sell the land.

Proponents of this model point out that it guarantees the stability and security of tenants and the community networks in their neighborhoods. They clarify that, for years, many renters have borne the maintenance costs of the apartments and buildings where they live, have invested in fixing them up, or have made extra payments to landlords to obtain or maintain their contracts.

A thorny issue

On the other hand, there’s a more thorny issue, especially for the government: many of these tenants are low-income families who cannot afford the market rent, nor can they afford to buy. If their contracts are abruptly liberalized, the result could be hundreds of thousands of evictions at once. The minimum wage in Egypt’s private sector — which, in many cases, isn’t even enforced — is only around $143 per month. This has led many to wonder why, for decades, the authorities’ policies haven’t been able to ensure that the majority of Egyptians can at least afford the cost of housing.

Faced with this situation, the staunchly pro-market government recently submitted a bill to parliament that would abruptly increase the price of old rents by 20%, with a minimum base of 1,000 pounds ($20) in the cities and half of that in the villages. These rents would then increase by 15% annually for five years. And, once this period is over, the bill stipulates that these contracts would become subject to market rates, like all the rest.

The legislation includes an article to ensure that those facing eviction receive priority access to social housing. However, these units may be located in areas that are very far from where the tenants have always lived.

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America

Trump’s Military Parade And The ‘No Kings’ Protests: Everything You Need To Know About This Saturday

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It will be a weekend of contrasts. This Saturday, a parade will be held in honor of the 250th anniversary of the United States Army, which falls on the same day as President Donald Trump’s 79th birthday. At the same time, people across the country are planning various protests against the Republican president and his immigration policy. These demonstrations, under the name “No Kings,” could face repression, as has happened in recent days in California, where the National Guard has been deployed and hundreds of arrests have been made.

On his social media platform Truth, the president said of the Army’s 250th anniversary: “We will celebrate with a spectacular military parade in Washington, D.C., like no other.” He also claimed that it would be bigger and better than any other parade ever seen on American soil. In fact, the U.S. Secret Service has designated it as a “special national security event,” similar to a presidential inauguration, which requires special resources. According to the Army, the cost of the event will be between $25 million and $45 million.

On the other hand, there are at least 2,000 protests planned against the Trump administration’s policies. Saturday has been called “No Kings Day of Defiance,” and its intention — according to the organizers — is to “honor civil liberties for all” and protest against deportations, U.S. actions in Gaza and support for Israel, mass layoffs of federal employees, and cuts to government departments such as USAID.

National Mall

Here’s what to expect this Saturday:

What time does the military parade start?

The military parade will take place on June 14 and will begin at 6:30 pm local time. The event is just one of several that will happen throughout the day from 8:30 am to 10:00 pm.

Parade schedule

The celebrations will begin with a traditional ceremony in which senior Army leaders lay a wreath at the Tomb of the Unknown Soldier at Arlington National Cemetery. An athletic competition will follow, and then a festival will be held at the National Mall from 11:00 am to 6:00 pm. The day will end with a fireworks display over the Tidal Basin.

The Army has announced that the parade will feature 6,700 soldiers, tanks, armored vehicles, rocket launchers, precision-guided missiles, and a flyover of 50 aircraft from different eras. The procession includes Abrams tanks, Bradley and Stryker vehicles, Paladin howitzers, helicopters, World War II aircraft such as the P-51 Mustang and C-47, and even a Sherman tank. Marching bands, horses, mules, and a dog named Doc Holiday will also participate.

What route will the parade take?

The parade will take place on Constitution Avenue in D.C., from 23rd Street to 15th Street, and will end near the White House. Upon arrival, a group of paratroopers with the Army’s Golden Knights will jump over the Ellipse to present the president with a folded flag.

Some 200,000 people are expected to attend the parade and the festival, which will be open to the public.

Protests against Trump

The “No Kings” protests were organized by the 50501 Movement (“50 States, 50 Protests, One Movement”), which consists of people who seek to defend democracy and who are against what they consider to be the authoritarianism of the Trump administration.

According to the movement, more than 2,000 protests will take place across the country, in its territories, and even in other countries. On its official website, there is a map showing all the locations where people will gather to demonstrate, and their mission statement, which reads as follows: “No Kings is a day of national rebellion. From city blocks to small towns, from courthouse steps to community parks, we are taking action to reject authoritarianism and show the world what democracy really looks like.”

They also refer to Flag Day, which is that same Saturday: “The flag does not belong to President Trump. It belongs to us. We are not watching history happen. We are creating it. On June 14, we will be everywhere he is not, to say no thrones, no crowns, no kings.”

Although the demonstrations are expected to be peaceful, some authorities have threatened those seeking to protest. In Florida, Brevard County Sheriff Wayne Ivey said, “If you throw a brick, a firebomb, or point a gun at one of our deputies, we will be notifying your family where to collect your remains at. Because we will kill you graveyard dead.” For his part, Governor Ron DeSantis addressed those who would not protest and suggested that they could run over protesters if they feared for their safety.

In Texas, Governor Greg Abbot has called on the state’s National Guard to be present during the protests. In Missouri, Governor Mike Kehoe said he would activate the National Guard, but said they would only be deployed if local authorities needed assistance.

Defense Secretary Pete Hegseth said he could deploy National Guard troops to other states beyond California “if necessary.” “Thankfully, in most of those states you have a governor that recognizes the need for (the National Guard), supports it, mobilizes it for himself or herself,” he said. “In California, unfortunately, the governor (Gavin Newsom) wants to play politics with it.” Newsom has sued Trump for deploying the National Guard during the protests that have rocked the city of Los Angeles over the past week and spread to the rest of the country.

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