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Baby Turtle Turns Into a Male, Adding Fresh Dimensions to Temperature-Dependent Sex Determination Theory
Inching closer to cracking the 50-year-old puzzle of how temperature turns baby turtles male or female, researchers have uncovered a molecular link that connects temperature with sexual development.
In turtles and other reptiles, whether an egg hatches male or female depends on the temperature of its nest.
The phenomenon was first discovered in reptiles more than 50 years ago, but until now the molecular details were a mystery.
In a study published in the journal Science, the researchers said they have finally identified a critical part of the biological “thermometer” that turns a developing turtle male or female.
The explanation lies not in the DNA sequence itself — the A’s, T’s, C’s and G’s — but in a molecule that affects how genes are expressed without altering the underlying genetic code, the researchers said.
“Temperature-dependent sex determination has been a puzzle for a really long time,” said Blanche Capel, Professor at Duke University in North Carolina, US.
“This is the first functional evidence of a molecular link that connects temperature with sexual development,” Capel said.
Unlike humans and most other mammals, the sex of many turtles, lizards, and alligators is not determined by the chromosomes they inherit, but by ambient temperatures during a sensitive stage of development.
For a common pond and pet turtle called the red-eared slider, for example, eggs incubated at 32 degrees Celsius produce all female hatchlings, while those kept at 26 degrees Celsius hatch as males.
In the study, the researchers showed that cooler egg incubation temperatures turn up a key gene called Kdm6b in the turtle’s immature sex organs, or gonads.
This, in turn, acts as a biological “on” switch, activating other genes that allow testes to develop.
To home in on the critical Kdm6b gene, the researchers took a group of freshly laid turtle eggs, incubated them at either 26 or 32 degrees Celsius, and looked for differences in the way genes were turned on in the turtles’ gonads early in development — before their fate as ovaries or testes has been decided.
Further experiments showed that the protein encoded by the Kdm6b gene, in turn, interacts with a region of the genome called Dmrt1, which acts as a master switch to turn on testis development.
“The next step is to find the temperature-sensing trigger,” said study co-author Ceri Weber, a Ph.D. candidate in the Capel lab at Duke.
“We’re trying to narrow down the possibilities,” Weber added. (IANS)
High drama was witnessed in Kanpur Dehat for over an hour when a man, upset over his wife's alleged affair with a local man, climbed the tower with his children and threatened to commit suicide. The incident took place on Monday near Gandhi Nagar in Akbarpur, when the man threatened to commit suicide after throwing his kids down from a height of nearly 40-feet. Chaos prevailed around the area and the locals informed the police that rushed to the spot.
After about half-an-hour of convincing, the police managed to bring him and his children down. The man told the police that his wife's affair was going on with his neighbor. He had complained to the police, but no action was taken. Police said that as per the man, his wife had developed an illicit relationship with a man, living nearby their house. "As per the man, in his absence, his neighbor visited his house often. He said that he had reprimanded his neighbor many times, but to no avail," said the police.
The man had complained to the police, but no action was taken. | Pixabay
The man had also lodged a complaint with the police but no action was taken. On the other hand, Akbarpur police said that on the basis of the complaint, action for breach of peace has been taken against the neighbor accused of luring his wife. Circle officer (CO) Akbarpur Arun Kumar said that the police are trying to sort out the issue. "Whatever action is appropriate will be taken," the official added. (IANS/SP)
(Keywords : Kanpur, Uttar Pradesh, man, wife, alleged, affair, children, India, police, neighbor, complaint, suicide, accuse, drama.)
The US forces continued their bombardment of buildings and institutions in Syria's northeastern Hasakah province, as part of their alleged manhunt of Islamic State (IS) fugitives, state news agency SANA reported. The US forces are shelling buildings and public institutions on Tuesday in the vicinity of the Sina'a prison in the Gweiran neighborhood in Hasakah "on the pretext of hunting down IS militants who fled the prison," said SANA.
The Syrian Foreign Ministry has slammed the US airstrikes as civilian casualties have been reported. | Wikimedia Commons
The shelling came in tandem with waves of raids by the Kurdish-led Syrian Democratic Forces (SDF) to homes in the surrounding areas, rounding up many civilians and taking them to unknown locations, the state news agency added. On January 20, IS inmates inside the Sina'a prison, which is controlled by the SDF, started a riot that was coordinated with IS militants from outside, who detonated the prison's gates with two booby-trapped vehicles, succeeding to free some prisoners.
The incident triggered clashes between IS and the SDF as well as US airstrikes on the areas, where the IS fugitives could have sought shelter in, Xinhua news agency reported. The clashes and airstrikes are still ongoing as the SDF has so far failed to contain the situation and storm the prison. The Syrian Foreign Ministry has slammed the US airstrikes as civilian casualties have been reported. Hasakah province is largely controlled by the US-backed SDF, while certain areas, particularly in the city of Qamishli, are still under the control of the Syrian government. (IANS/ MBI)
(Keywords: US forces, shelling, bombarding, syria, islamic state, civilian casualties, qamishli, tandem, syrian democratic forces)
The circulating avian influenza outbreaks, including in India, do not seem to pose the 'high' risk but surveillance and biosecurity measures are necessary to reduce spillover risk between poultry and wild birds, a UN-backed scientific task force said. Throughout the past autumn and current winter in the northern hemisphere, multiple avian influenza outbreaks, caused predominantly by the H5N1 HPAI virus, plus other subtypes, including H5N8, have occurred in India, the UK, the Netherlands and Israel with the ever recorded mortality of the Svalbard barnacle geese in Solway Coast.
The Scientific Task Force on Avian Influenza and Wild Birds, co-convened by the Convention on the Conservation of Migratory Species of Wild Animals (CMS) and the UN's Food and Agriculture Organization (FAO), on Monday recommended that surveillance and biosecurity measures are reinforced to reduce spillover risk between poultry and wild birds. The Task Force has convened and produced recommendations and guidance for authorities and managers of countries affected or at risk. Wild birds, including globally threatened species, are victims of HPAI viruses causing avian influenza. Affected sites also include areas of international relevance for conservation such as protected wetlands.
More than 2,400 migratory water birds died in the Pong wetlands in Himachal last year because of avian influenza. | Unsplash
It is essential that authorities with responsibility for animal health apply the One Health approach for communicating and addressing avian influenza. That means recognising the health of humans, domestic and wild animals, plants, and the wider environment and acting with a coordinated and unified approach. The Task Force reminds authorities of their international obligations to ensure their response to the pathogenic virus does not include the culling of wild birds, nor actions that would cause damage to natural ecosystems, especially wetlands.
Ruth Cromie, who coordinated the work of the Task Force and the production of the statement, said: "Avian influenza represents a One Health issue threatening health across the board. The highly pathogenic viruses are still relatively new in wild birds and this winter's high levels of mortality remind us of their vulnerability and that working to promote healthy wildlife benefits us all." H5N1 is currently the avian influenza lineage most found in Africa and Eurasia in both poultry and wild birds. The wide range of wild birds affected include wildfowl, waders, gulls, cranes, grebes, herons, pelicans, gamebirds, corvids and raptors (diurnal and nocturnal), in addition to sporadic cases in mammals such as red fox (Vulpes vulpes), Eurasian otter (Lutra lutra) and harbor Phoca vitulina and grey seal Halichoerus grypus.
Consider occupational exposure, e.g. those working on poultry culling operations. | Unsplash
In terms of human health, the currently circulating H5N1 HPAI viruses do not seem to pose the same zoonotic risk as the 'original' Asian lineage H5N1 (clade 2.2 and their derivatives plus clade 22.214.171.124b H5N6 viruses currently in China). In general, the risk can be considered low, recognising that some agencies now consider occupational exposure, e.g. those working on poultry culling operations, as low or moderate. In India, several instances of bird flu were reported in 2021. More than 2,400 migratory water birds, and almost half of them being endangered bar-headed goose, died in the Pong wetlands in Himachal Pradesh last year and that avian influenza (H5N1) was the cause.
Besides the bar-headed goose, the other species that died were the shoveler, the river tern, the pochard and the common teal. An 11-year-old boy died at All India Institute of Medical Sciences in Delhi last year due to avian influenza, country's first fatality. India reported the first outbreak of avian influenza in 2006. RSPB Scotland is calling for an emergency local moratorium restricting shooting on the Solway for the rest of the wildfowling season. It calls for urgent action to reduce the devastating impacts of avian influenza. New statistics from the most recent counts show that the UK is this winter experiencing the worst outbreak of this deadly disease on record, with migratory geese which 'over winter' on the Solway being the hardest hit.
According to RSPB Scotland, the latest population counts of the Svalbard barnacle goose show a drop in numbers from 43,703 in November last year to 27,133 in this month's count. This represents a decline of 38 per cent in the Svalbard breeding population of this species from winter 2020-21. CMS Executive Secretary Amy Fraenkel said: "Through late 2021 and early 2022 there have been numerous outbreaks of highly pathogenic avian influenza H5N1, with severe impacts on migratory birds. "The CMS Secretariat responded by convening the Scientific Task Force on Avian Influenza and Wild Birds together with the FAO. We are pleased to share its advice and key recommendations for countries affected or at risk, and look forward to continuing our collaborative work to minimize risks to humans, poultry and wild populations of migratory birds." (IANS/SP)
(Keywords : avian, influenza, surveillance, United Nation, scientists, breeding, population, birds, affected, countries, poultry, migratory, health, issue, virus, responsibility, international, ecosystem.)