Decades-old question surrounding the start of the tree of life could finally be solved

Published

2 years ago

May 25, 2023

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A blood-belly comb jelly Lampocteis cruentiventer collected off the coast of San Diego. (Image credit: Yiming Chen/Getty Images)

After decades of debate, scientists believe they have identified the most recent ancestor of the sister to all animals via the novel use of an analytical technique. The finding settles a central question about the evolution of the entire tree of animal life.

All animal life is descended from a single common ancestor — a multicellular organism that most likely lived more than 600 million years ago. This ancestor had two offspring; one that led to the evolution of all animal life, and another that is referred to as the sister to all animals.

In the quest to identify which living animals are most closely related to this sister group, scientists have narrowed down the possibilities to two candidates: sea sponges and comb jellies (ctenophores). Conclusive evidence to support either candidate, however, has remained elusive.

Now, a new study published May 17 in the journal Nature has resolved this long-running debate with the novel use of chromosomal analysis.

The debate over the ancestors of sea sponges (left) and comb jellies (right) has been going on for decades. (Image credit: Reinhard Dirscherl/RibeirodosSantos/Getty Images)

The solution came while Darrin T Schultz, lead author and current postdoctoral researcher at the University of Vienna, and a multi-institutional team were sequencing the genomes (the complete set of genetic information) of comb jellies and their close relatives to understand more about their evolution.

Related: Alien-like comb jellies have a nervous system like nothing ever seen before

Rather than comparing individual genes, the team looked at their positions on chromosomes across species. While changes to DNA occur over the course of evolution, genes tend to remain on the same chromosome. On rare occasions of fusion and mixing, genes transfer from one chromosome to another in an irreversible process. Schultz compares this to shuffling a deck of cards. If you have two decks of cards and you shuffle them, they become mixed. “Once mixed, you can’t unmix it in the way it was before, the probability of that is almost impossible,” Schultz told Live Science.

In other words, once a gene has moved from one chromosome to another, there is almost zero chance of it appearing in its original position again further down the evolutionary line. By looking at the large-scale movement of groups of genes across animal groups, Schultz and the team were able to gain important insights into the family tree of these animals.

The team found 14 groups of genes that appeared on separate chromosomes in comb jellies and their single-celled, non-animal relatives. Interestingly, in sponges and all other animals, these genes had rearranged into seven groups.

Given that the DNA of the comb jellies holds the gene groups in their original position (prior to rearranging into the seven groups) it is indicative that they are descendants of the sister group that broke from the animal family tree, before the mixing occurred. RELATED STORIES—What’s the weirdest sea creature ever discovered?

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Further, the gene location rearrangements that were common to both sponges and all other animals suggest a shared ancestor from which these rearrangements were inherited. The findings, therefore, resolve the controversial question over the lineage of the entire animal tree of life.

Since the ancestors of comb jellies and sponges branched off from the family tree, their modern descendants have continued to evolve, so we cannot use this information to indicate what the first animals exactly looked like. However, scientists believe there is significant value in studying these modern animals in light of this new information about their lineage. “If we understand how all animals are related to one another, it helps us understand how animals evolved the things that make them animals,” Schultz said.

US

Charlie Kirk posthumously awarded Presidential Medal of Freedom by Donald Trump

Published

1 hour ago

October 15, 2025

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Charlie Kirk posthumously awarded Presidential Medal of Freedom by Donald Trump

Charlie Kirk has been posthumously awarded the Presidential Medal of Freedom by Donald Trump.

The USA’s highest civilian honour was received by the conservative activist’s widow, Erika, at the White House.

Mr Kirk, 31, was fatally shot on 10 September while speaking at an event at Utah Valley University.

He founded Turning Point USA and toured American university campuses, debating students about current affairs.

Addressing those attending the ceremony in the White House rose garden, the US president said they were there to “honour and remember a fearless warrior for liberty” and a “beloved leader who galvanised the next generation”.

He said Mr Kirk’s name was being entered “forever into the eternal roster of true American heroes”.

Mr Trump described Charlie Kirk as an “American patriot of the deepest conviction, the finest quality and the highest calibre”.

He said his nation had been “robbed” of an “extraordinary champion”.

And Mr Trump said Mr Kirk was assassinated in the “prime of his life for boldly speaking the truth, for living his faith, and relentlessly fighting for a better and stronger America”.

The ceremony coincided with what would have been Mr Kirk’s 32nd birthday.

Mr Trump described Erika Kirk, now head of Turning Point USA, as someone who had “endured unspeakable hardship with unbelievable strength”.

A 22-year-old man, Tyler Robinson, from the city of Washington in Utah has been charged with Mr Kirk’s murder. Prosecutors said they would seek the death penalty.

At a memorial event held at a stadium in Arizona, Erika Kirk told an enormous crowd she forgave her husband’s killer.

“The answer to hate is not hate,” she said.

US

Grammy-winning R&B and soul star D’Angelo dies after ‘prolonged battle with cancer’

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1 hour ago

October 15, 2025

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Grammy-winning R&B and soul star D'Angelo dies after 'prolonged battle with cancer'

Grammy-award winning R&B and soul singer D’Angelo has died following a battle with pancreatic cancer, his family has said.

He died on Tuesday, leaving behind a “legacy of extraordinarily moving music” following a “prolonged and courageous battle with cancer,” his family said in a statement.

The prominent musician, born Michael D’Angelo Archer, was 51 years old.

A family statement said: “We are saddened that he can only leave dear memories with his family, but we are eternally grateful for the legacy of extraordinarily moving music he leaves behind.

“We ask that you respect our privacy during this difficult time, but invite you all join us in mourning his passing while also celebrating the gift of song that he has left for the world.”

The singer rose to prominence in the 1990s with his first album, Brown Sugar.

The track “Lady” from that album reached No. 10 in March 1996 and remained on Billboard’s Hot 100 chart for 20 weeks.

Entertainment

Stars of sumo head to London’s Royal Albert Hall – and noodles sell out

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2 hours ago

October 15, 2025

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Stars of sumo head to London's Royal Albert Hall - and noodles sell out

They’re getting through 70kg of rice a day and the wholesaler has run out of noodles. Yes, Sumo returns to London on Wednesday.

It’s just the second time a Grand Tournament has been held outside of Japan – and this is a sport that has records going back more than 1,500 years.

It’s 34 years since the Royal Albert Hall hosted the only previous such event on foreign soil – and the appetite for tickets meant all five days sold out immediately.

Much of the focus is on the two grand champions or yokozuna, the 74th and 75th men to attain the rank.

They’re the Mongolian Hoshoryu Tomokatsu, plus Japan’s Onosato Daiki – who this year became the quickest wrestler to achieve the rank in the modern era.

“I’m happy that Sumo is back after so many years,” Onosato said. “I hope I can show the UK fans how fantastic Sumo is.”

“Being a yokozuna has a lot of responsibility,” Hoshoryu told Sky Sports. “We have to show everyone an example of what a yokozuna is – and that’s very difficult.

“My uncle was a yokozuna – and I’m happy to follow in his footsteps. But I came here to London as a yokozuna which he didn’t, so I’m even happier.”

The two are already great rivals.

At the recent Aki Basho – the most prestigious tournament on the sumo calendar – the pair finished with identical records after 15 days of bouts.

It all came down to a final play-off between the two yokozuna – the first time that had happened in 16 years. It was Onosato who came out on top on that occasion.

Hoshoryu says he is a big fan of basketball and football. He follows Chelsea, although his favourite players are going back a bit: “Didier Drogba and Petr Cech. He’s the ‘keeper. I like this guy!”

Early starts and a hearty stew: The life of a rikishi

The wrestlers – or rikishi – have a rigorous training regime.

They live in communal blocks called stables and practice starts early. Perhaps surprisingly, everyone skips breakfast. After training and practice – and for the younger rikishi, chores – the wrestlers all eat together.

The staple of their diet is chankonabe, a hearty stew packed with meat and vegetables. The feeding of the 40 rikishi who have come over for the five-day tournament is a challenge in itself.

Donagh Collins, the CEO of co-organisers Askonas Holt, said: “We are going through 70 kilos of rice a day. Somebody told me that the wholesaler for the noodles has run out of noodles. We’re really pushing the system here.”

The ring – or dohyo – is just 4.55m in diameter and quite small when two giant wrestlers leap at each other.

The aim of the fights is to either get your opponent onto the floor – or, more spectacularly, shove or hurl them out of the dohyo, so spectators in the ringside seats may be getting extremely up-close to the wrestlers.

The last time the tournament was in Britain, the massive Konishiki, known as the Dump Truck, took centre stage.

The giant Hawaiian was the heaviest-ever rikishi coming in at 287kg – or 45 stone. That’s a lot of wrestler to dodge if he comes falling out of the ring towards you.

The Royal Albert Hall may be firstly a concert venue, but it has hosted the likes of John McEnroe, Lennox Lewis and even Muhammad Ali.

And for the next five days, the cream of the world of sumo will be thrilling the crowds – provided a new noodle supplier is found.

What is a yokozuna?

Yokozuna is the highest rank in sumo, with its name meaning “horizontal rope” and refers to the rope worn around a competitor’s waist as they enter the ring.