There was a time when humans had tails, but thanks to evolution, certain changes ensured that the tail vanished. Nearly 25 million years ago, the tails of human beings disappeared.

There was a time when humans had tails, but thanks to evolution, certain changes ensured that the tail vanished. Nearly 25 million years ago, the tails of human beings disappeared. Scientists have now found out what exactly happened that led to this change during the evolution process. The secret behind the disappearance of the tail was discovered by researchers from New York University Langone Health. They identified a single snippet of DNA, which is commonly found in apes and humans but has been missing from monkeys. The new study was published in the prestigious journal Nature. "Our study begins to explain how evolution removed our tails, a question that has intrigued me since I was young," said lead study author Bo Xia. Also Read: A silent warning? Microplastics found in every human placenta, reveals new study The answer is present in the gene TBXT which is present in the tail length in certain animals. As per the study, the gene was not found in humans, not due to mutation but because another genetic code "snippet" known as AluY was randomly inserted inside non-tailed apes and early humans during prehistoric times, as per the study. How the gene affected tail length? The new gene was observed to affect tail lengths. When it was paired with TBXT, the new gene created two types of ribonucleic acid, which are important for cellular structure and led to the disappearance of tails in people and apes. "This finding is remarkable because most human introns carry copies of repetitive, jumping DNAs without any effect on gene expression, but this particular AluY insertion did something as obvious as determine tail length," said Dr Jef Boeke, the Sol and Judith Bergstein Director of the Institute for Systems Genetics, as reported by the New York Post. AluY snippets are also known as "jumping genes" or "mobile elements" since they are able to move around and insert themselves repeatedly and in random order in human code. Watch: Study: Apes like to tease their friends The scientists used mice to test their theory and inserted AluY into 63 of them. It was found by the researchers that the tails of offspring were either completely missing or had shortened. These experiments proved that tail loss may also coincide with an increase in neural tube defects which can cause diseases like spina bifida in people. In this disease, the spine does not properly align with the spinal cord. "Future experiments will test the theory that in an ancient evolutionary trade-off, the loss of a tail in humans contributed to the neural tube birth defects," study author Dr Itai Yanai said. (With inputs from agencies)

Here's why human tails disappeared 25 million years ago

Here, we bring you the news that is trending across WION's social media platforms- The reason why humans lost their tails 25 million years ago is down to a single snippet of DNA, a new study has revealed. Scientists have discovered the genetic change in our ancient ancestors which could explain why humans don’t have tails like monkeys.

Why Humans lost their tails 25 million years ago revealed | Trending on WION

A recent study suggests that dogs wag their tail not only to indicate happiness but also to communicate other complex emotions. A team of European researchers proposed two major theories on the evolution of tail wagging in dogs in a recent study published in the journal Biology Letters.

A recent study suggests that dogs wag their tail not only to indicate happiness but also to communicate other complex emotions. A team of European researchers proposed two major theories on the evolution of tail wagging in dogs in a recent study published in the journal Biology Letters. The study suggests that when dogs experience a positive emotion, they tend to wag their tail more towards the right. However, their wagging inclines towards the left more when they have a negative emotion. The authors stated that wagging and arousal-related hormones or neurotransmitters might be linked in the dogs' bodies. They also mentioned that there might be a connection between the stress hormone cortisol and tail wagging. Silvia Leonetti, the study's first author and research assistant in comparative bioacoustics at the Max Planck Institute for Psycholinguistics, told Newsweek, "Many animals have tails and use those tails for moving (an alligator swimming), balance ( a cat walking along a narrow fence), and removing pests (a horse swatting flies away from its body). But those examples contrast with domestic dogs, who use their tails primarily for communication rather than any other function." ALSO READ | Rhesus monkey cloned using new technique different from what was used for Dolly the sheep Dogs, compared to wolves, wag their tails more often and start from a very young age, suggesting that the behaviour evolved in the line after humans started domesticating them. Thus, dogs might have adapted wagging as a way to communicate with their human masters. "One study found that during food denial situations, dogs wagged their tails more when a human was present versus not, suggesting that tail wagging may also function as a requesting signal," the authors said. However, this evolution might not be deliberate. According to the study, wagging may have emerged as a by-product of another characteristic, like tameness or friendliness. The authors bred a cohort of silver foxes for over 40 generations for the research. They found that the foxes showed a dog-like tail-wagging behaviour after being selected for traits like tamability and docility. "Based on this, we hypothesise that the domestication process may have led to changes at the anatomical and behavioral level that altered tail wagging behavior in dogs," the authors said. Although these theories suggest how and why tail wagging evolved, there are many unanswered questions. "We are just scratching the surface," Andrea Ravignani, the study's senior author, said. It remains a mystery how dogs control their behaviour and how well they decipher the meaning of wagging among other dogs. "We echo the concerns of other researchers that these procedures may impair the communicative repertoire of an animal (although this should be empirically tested by comparing breeds) and reduce how well a dog can express its feelings and communicate," Ravignani said. (With inputs from agencies)

Dogs wag their tail to convey a lot more than just happiness, study finds

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