Jun 25, 2021 11:23 PM
(This post was last modified: Jun 25, 2021 11:46 PM by C C.)
A single bee is creating an army of clones bent on wiping out another bee species
https://www.sciencealert.com/a-single-be...ies-of-bee
EXCERPTS: When hives of the African lowland honeybee (Apis mellifera scutella) collapse, they do so because of an invisible inner threat: the growing, immortal clone army of a rival bee subspecies.
That army is possible because the female workers of the rival subspecies – the South African Cape honeybee (Apis mellifera capensis) – can create perfect copies of themselves, with one individual found to have done so millions of times in the past three decades.
With this perpetual-cloning ability, the Cape honeybees sneak into the hives of their lowland honeybee rivals and churn out copy after copy (no need for a queen). Even worse, these clones are freeloaders, refusing to do any work.
Now, a new study has revealed the genetic foundations of the strange and formidable adaptation.
Unlike most animals, and even their own queen, the female workers do not reshuffle the DNA of the eggs they lay. This enables the workers to consistently recreate a perfect copy of themselves – a clone – each time they reproduce.
According to the researchers, the sidestepping of this DNA-reshuffling process is unlike anything they've ever seen.
"It's incredible. It's also incredibly dysfunctional," lead author Benjamin Oldroyd, a professor of behavioral genetics at the University of Sydney, told Live Science, referring to the fact that reshuffling is normally required to hold chromosomes together during the egg-making process."Yet, somehow they've managed to do it [still lay eggs]. It's insane; I've not heard of anything like this before, anywhere."
[,,,] The workers' ability to clone at will places their colonies in a much more precarious position, especially once the queen leaves or dies and the old social order collapses. Instead of expending energy to get the colony back on its feet, workers will dedicate themselves to selfish schemes – such as finding ways to place their clones into positions of power.
"If you take the queen away, for instance, instead of raising a new queen like other bee species might, these bees will just start laying eggs themselves," Oldroyd said. "There are also cells, called queen cells, where the queen lays the eggs containing future queens. It's perfectly possible for a worker to fly in from another colony, or one of the existing workers in that colony to come and replace that queen egg with one of their clone eggs. That way, they can be genetically reincarnated as a queen."
But one lineage of Cape bee workers has taken this socially parasitic behavior even further, to the point where they no longer need a queen, and they solely exist by taking over the hives of the African lowland honeybee.
Members belonging to a single branch of rogue clone Cape bee workers sneak into African lowland honeybee hives, which are commonly used for agricultural purposes, and lay as many eggs as they can, which the African lowland bees mistake for their own and rear.
The parasitic clone Cape bee larvae are in on this ruse, even sending signals to their unfortunate hosts to feed them as much as possible. This cuckoo-like behavior allows them to grow their bodies and their ovaries almost to the size of a queen's.
"The Cape bee clones don't do any work inside those hives because they've become reproductive," Oldroyd said. "They just strut around with this attitude like, 'Yeah, you're going to work for me.' It very quickly leads to the collapse of the hive. As individuals, these clones are quite dysfunctional, so you'd expect them to peter out. But they're a lot like the cells in a tumor in this regard – it doesn't matter if every clone is healthy, so long as enough of them are around to exploit the host."
The Cape bee workers that take part in this parasitic behavior are the genetically identical descendants of a single worker that lived in 1990, according to Oldroyd. This single lineage of clones is responsible for the collapse of 10 percent of African lowland honeybee colonies every year... (MORE - missing details)
New human species type unknown to science found, lived 420,000 to 120,000 years ago (intro): An international group of archaeologists have discovered a missing piece in the story of human evolution. Excavations at the Israeli site of Nesher Ramla have recovered a skull that may represent a late-surviving example of a distinct Homo population, which lived in and around modern-day Israel from about 420,000 to 120,000 years ago. As researchers Israel Hershkovitz, Yossi Zaidner and colleagues detail in two companion studies published today in Science, this archaic human community traded both their culture and genes with nearby Homo sapiens groups for many thousands of years... (MORE)
- - - - -
Dramatic discovery in Israeli excavation (key points): The discovery of a new Homo group in this region, which resembles Pre-Neanderthal populations in Europe, challenges the prevailing hypothesis that Neanderthals originated from Europe, suggesting that at least some of the Neanderthals' ancestors actually came from the Levant.
The new finding suggests that two types of Homo groups lived side by side in the Levant for more than 100,000 years (200-100,000 years ago), sharing knowledge and tool technologies: the Nesher Ramla people who lived in the region from around 400,000 years ago, and the Homo sapiens who arrived later, some 200,000 years ago.
The new discovery also gives clues about a mystery in human evolution: How did genes of Homo sapiens penetrate the Neanderthal population that had presumably lived in Europe long before the arrival of Homo sapiens?
The researchers claim that at least some of the later Homo fossils found previously in Israel, like those unearthed in the Skhul and Qafzeh caves, do not belong to archaic (early) Homo sapiens, but rather to groups of mixed Homo sapiens and Nesher Ramla lineage. (MORE - details)
'Dragon man' claimed as new species of ancient human but doubts remain
https://www.newscientist.com/article/228...ts-remain/
EXCERPTS: A large fossil skull discovered in China may belong to one of our mysterious long-lost relatives, the Denisovans, potentially offering us our first glimpse of a Denisovan face. It has, however, been placed in a new human species – Homo longi – a name that derives from a Chinese term meaning “dragon”, and that means the early hominin may become known informally as “dragon man”.
Other researchers say the discovery is important and exciting, but think the decision to add a new species to our family tree is premature. [...] “This is biggest human skull I’ve seen – and I’ve seen a few,” says Chris Stringer at the Natural History Museum, London, who was also a member of the team.
The researchers estimate that the skull belonged to a man who was about 50 years old when he died, between 146,000 and 296,000 years ago. Its features are a mix of those seen in archaic and modern humans. It has thick brow ridges, for example, yet “the face looks so much like a bigger version of a modern human face”, says Stringer. Its brain size was similar to ours too.
“It’s got such an interesting combination of features,” says Stringer. “The morphology shows that this is definitely a distinct lineage in eastern Asia. It’s not Neanderthal and it’s not Homo sapiens, it’s something quite distinctive,” says Stringer.
One possibility is that the Harbin fossil is a Denisovan. This mysterious group of extinct humans was first identified a decade ago from DNA in a finger bone found in the Denisova cave in Siberia, Russia. The Denisovans were closely related to the Neanderthals, and lived in Asia for hundreds of thousands of years. They also interbred with H. sapiens... (MORE -details)
RELATED: 'Dragon man' fossil may replace Neanderthals as our closest relative
https://www.sciencealert.com/a-single-be...ies-of-bee
EXCERPTS: When hives of the African lowland honeybee (Apis mellifera scutella) collapse, they do so because of an invisible inner threat: the growing, immortal clone army of a rival bee subspecies.
That army is possible because the female workers of the rival subspecies – the South African Cape honeybee (Apis mellifera capensis) – can create perfect copies of themselves, with one individual found to have done so millions of times in the past three decades.
With this perpetual-cloning ability, the Cape honeybees sneak into the hives of their lowland honeybee rivals and churn out copy after copy (no need for a queen). Even worse, these clones are freeloaders, refusing to do any work.
Now, a new study has revealed the genetic foundations of the strange and formidable adaptation.
Unlike most animals, and even their own queen, the female workers do not reshuffle the DNA of the eggs they lay. This enables the workers to consistently recreate a perfect copy of themselves – a clone – each time they reproduce.
According to the researchers, the sidestepping of this DNA-reshuffling process is unlike anything they've ever seen.
"It's incredible. It's also incredibly dysfunctional," lead author Benjamin Oldroyd, a professor of behavioral genetics at the University of Sydney, told Live Science, referring to the fact that reshuffling is normally required to hold chromosomes together during the egg-making process."Yet, somehow they've managed to do it [still lay eggs]. It's insane; I've not heard of anything like this before, anywhere."
[,,,] The workers' ability to clone at will places their colonies in a much more precarious position, especially once the queen leaves or dies and the old social order collapses. Instead of expending energy to get the colony back on its feet, workers will dedicate themselves to selfish schemes – such as finding ways to place their clones into positions of power.
"If you take the queen away, for instance, instead of raising a new queen like other bee species might, these bees will just start laying eggs themselves," Oldroyd said. "There are also cells, called queen cells, where the queen lays the eggs containing future queens. It's perfectly possible for a worker to fly in from another colony, or one of the existing workers in that colony to come and replace that queen egg with one of their clone eggs. That way, they can be genetically reincarnated as a queen."
But one lineage of Cape bee workers has taken this socially parasitic behavior even further, to the point where they no longer need a queen, and they solely exist by taking over the hives of the African lowland honeybee.
Members belonging to a single branch of rogue clone Cape bee workers sneak into African lowland honeybee hives, which are commonly used for agricultural purposes, and lay as many eggs as they can, which the African lowland bees mistake for their own and rear.
The parasitic clone Cape bee larvae are in on this ruse, even sending signals to their unfortunate hosts to feed them as much as possible. This cuckoo-like behavior allows them to grow their bodies and their ovaries almost to the size of a queen's.
"The Cape bee clones don't do any work inside those hives because they've become reproductive," Oldroyd said. "They just strut around with this attitude like, 'Yeah, you're going to work for me.' It very quickly leads to the collapse of the hive. As individuals, these clones are quite dysfunctional, so you'd expect them to peter out. But they're a lot like the cells in a tumor in this regard – it doesn't matter if every clone is healthy, so long as enough of them are around to exploit the host."
The Cape bee workers that take part in this parasitic behavior are the genetically identical descendants of a single worker that lived in 1990, according to Oldroyd. This single lineage of clones is responsible for the collapse of 10 percent of African lowland honeybee colonies every year... (MORE - missing details)
New human species type unknown to science found, lived 420,000 to 120,000 years ago (intro): An international group of archaeologists have discovered a missing piece in the story of human evolution. Excavations at the Israeli site of Nesher Ramla have recovered a skull that may represent a late-surviving example of a distinct Homo population, which lived in and around modern-day Israel from about 420,000 to 120,000 years ago. As researchers Israel Hershkovitz, Yossi Zaidner and colleagues detail in two companion studies published today in Science, this archaic human community traded both their culture and genes with nearby Homo sapiens groups for many thousands of years... (MORE)
- - - - -
Dramatic discovery in Israeli excavation (key points): The discovery of a new Homo group in this region, which resembles Pre-Neanderthal populations in Europe, challenges the prevailing hypothesis that Neanderthals originated from Europe, suggesting that at least some of the Neanderthals' ancestors actually came from the Levant.
The new finding suggests that two types of Homo groups lived side by side in the Levant for more than 100,000 years (200-100,000 years ago), sharing knowledge and tool technologies: the Nesher Ramla people who lived in the region from around 400,000 years ago, and the Homo sapiens who arrived later, some 200,000 years ago.
The new discovery also gives clues about a mystery in human evolution: How did genes of Homo sapiens penetrate the Neanderthal population that had presumably lived in Europe long before the arrival of Homo sapiens?
The researchers claim that at least some of the later Homo fossils found previously in Israel, like those unearthed in the Skhul and Qafzeh caves, do not belong to archaic (early) Homo sapiens, but rather to groups of mixed Homo sapiens and Nesher Ramla lineage. (MORE - details)
'Dragon man' claimed as new species of ancient human but doubts remain
https://www.newscientist.com/article/228...ts-remain/
EXCERPTS: A large fossil skull discovered in China may belong to one of our mysterious long-lost relatives, the Denisovans, potentially offering us our first glimpse of a Denisovan face. It has, however, been placed in a new human species – Homo longi – a name that derives from a Chinese term meaning “dragon”, and that means the early hominin may become known informally as “dragon man”.
Other researchers say the discovery is important and exciting, but think the decision to add a new species to our family tree is premature. [...] “This is biggest human skull I’ve seen – and I’ve seen a few,” says Chris Stringer at the Natural History Museum, London, who was also a member of the team.
The researchers estimate that the skull belonged to a man who was about 50 years old when he died, between 146,000 and 296,000 years ago. Its features are a mix of those seen in archaic and modern humans. It has thick brow ridges, for example, yet “the face looks so much like a bigger version of a modern human face”, says Stringer. Its brain size was similar to ours too.
“It’s got such an interesting combination of features,” says Stringer. “The morphology shows that this is definitely a distinct lineage in eastern Asia. It’s not Neanderthal and it’s not Homo sapiens, it’s something quite distinctive,” says Stringer.
One possibility is that the Harbin fossil is a Denisovan. This mysterious group of extinct humans was first identified a decade ago from DNA in a finger bone found in the Denisova cave in Siberia, Russia. The Denisovans were closely related to the Neanderthals, and lived in Asia for hundreds of thousands of years. They also interbred with H. sapiens... (MORE -details)
RELATED: 'Dragon man' fossil may replace Neanderthals as our closest relative