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Thread: The details of human evolution grows through discoveries and genetics

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    The details of human evolution grows through discoveries and genetics

    The details of the diversity and evolution of our evolution increases over time with more discoveries and advances in genetics.

    Source: https://www.bbc.com/news/science-environment-51508616



    'Ghost' human ancestor discovered in West Africa

    A mysterious "ghost population" of now-extinct ancient human-like creatures may have interbred with early humans living in West Africa, scientists say.

    Researchers suggest DNA from this group makes up between 2% and 19% of modern West Africans' genetic ancestry.

    They believe the interbreeding occurred about 43,000 years ago.

    Scientists found links to the Mende people of Sierra Leone, Yoruba as well as Esan people in Nigeria, plus other groups in western areas of The Gambia.

    The new study was published in Science Advances this week.

    It suggests that ancestors of modern West Africans interbred with a yet-undiscovered species of archaic human, similar to how ancient Europeans mated with Neanderthals, and Oceanic populations with Denisovans.

    Neanderthals 'dived in the ocean' for shellfish
    Cave girl was half Neanderthal, half Denisovan
    Viewpoint: Why we still underestimate the Neanderthals
    The research sheds more light on how archaic hominins added to the genetic variation of present-day Africans, which has been poorly understood even though it is the most genetically diverse continent.

    Hundreds of thousands of years ago there were several different groups of humans including modern humans, Neanderthals and Denisovans.

    The newly-discovered "ghost population" of ancient human species seems likely to have diverged from these groups.

    Sriram Sankararaman - the computational biologist who led the research at the University of California in Los Angeles - told BBC Newsday he believed more such groups would be found in the future.

    His team looked at the genetic make-up of West Africans and found that some of their DNA came from an ancient unexplained source.

    "As we get more data from diverse populations - and better quality data - our ability to sift through that data and excavate these ghost populations is going to get better," Mr Sankararaman said.

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    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

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  2. #2
    Evolution is God's ID rogue06's Avatar
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    The full paper Recovering signals of ghost archaic introgression in African populations can be read HERE

    The Abstract from the paper:

    While introgression from Neanderthals and Denisovans has been documented in modern humans outside Africa, the contribution of archaic hominins to the genetic variation of present-day Africans remains poorly understood. We provide complementary lines of evidence for archaic introgression into four West African populations. Our analyses of site frequency spectra indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans. Using a method that can identify segments of archaic ancestry without the need for reference archaic genomes, we built genome-wide maps of archaic ancestry in the Yoruba and the Mende populations. Analyses of these maps reveal segments of archaic ancestry at high frequency in these populations that represent potential targets of adaptive introgression. Our results reveal the substantial contribution of archaic ancestry in shaping the gene pool of present-day West African populations.


    And from The Scientist:

    Source: Remnants of Extinct Hominin Species Found in West African Genomes


    A study points to the existence of an ancient human relative that interbred with Homo sapiens.

    An analysis of the whole genome sequences of hundreds of modern-day West Africans, along with those of ancient Neanderthals and Denisovans, points to the existence of a “ghost” species that interbred with Homo sapiens before dying out, researchers at the University of California, Los Angeles, report yesterday (February 12) in Science Advances.

    The finding further complicates an evolutionary history in which different hominin species diverged, only to—in some cases—meet up and swap genes with each other hundreds of thousands of years later. Modern humans have already been found to have interbred with Neanderthals and Denisovans.

    In the new study, Arun Durvasula and Sriram Sankararaman analyzed the whole-genome sequences of people from four populations living in Nigeria, Sierra Leone, and the Gambia, as well as those from Neanderthal and Denisovan fossils. They found patterns in the genomes of two of the modern groups, Yoruba and Mende, that indicated some of their DNA sequences originated in a species other than those analyzed.

    Whatever that species was, “They seem to have made a pretty substantial impact on the genomes of the present day individuals we studied,” Sankararaman tells The Guardian. “They account for 2% to 19% of their genetic ancestry.” He and Durvasula also found hints of the archaic species’ genes in a population in Kenya, and in individuals of Han Chinese and northern and western European ancestry.

    Sankararaman and Durvasula estimate that the ghost species split between 1 million and 360,000 years ago from the lineage that produced modern humans and Neanderthals, and that members of that species interbred with Homo sapiens sometime in the past 124,000 years.

    “It’s an exciting moment because these studies open a window showing us that there is much more than we thought to learn about our ancestors. But actually knowing who those ancestors were, how they interacted, and where they existed is going to take fieldwork to find their fossil and archaeological remains,” John Hawks, an anthropologist at the University of Wisconsin-Madison who was not involved in the study, tells The Guardian.

    The New York Times notes that one candidate for the ghost species is a hominin for which a skull was discovered in 2011 in Nigeria. But researchers have not yet succeeded in extracting and sequencing DNA from that fossil, or from others found in Africa that are thought to be from now-extinct hominins.


    Source

    © Copyright Original Source


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  3. Amen Juvenal amen'd this post.
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    tWebber shunyadragon's Avatar
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    A new discovery about the Australopithecus show more evidence of the evolution of earlier primates and later primates that lead to human evolution. This diversity of subspecies and varieties of the widespread adaptation Australpithecus is already known that lead to the evolution of humans. This discovery shows this variation of Australpithecus lived partially in trees.

    Source: https://www.9news.com.au/world/little-foot-australopithecus-lived-in-trees-was-vegetarian-say-researchers/921c0d91-196e-4c0e-a6ba-f5bb53a7c5e8



    Ancient human ancestor probably lived in trees

    Around 3.67 million years ago, an ancient human ancestor nicknamed Little Foot fell about 30 feet down into a deep shaft of a cave. Today, she represents the most complete Australopithecus skeleton and is helping researchers to learn more about our chimpanzee-like ancestors. Little Foot likely stood over just four feet tall. She would have slept in trees to remain safe from giant predators like sabre-toothed cats. And she was likely a vegetarian who munched on plants. Little Foot had powerful hands and a special big toe that allowed for better climbing.

    This week, researchers studying her skeleton learned something new. They shared that Little Foot was capable of different head movements than modern humans. This was likely due to the fact that Little Foot spent so much time in trees and was an expert climber. Humans have lost those special abilities and don't need their heads to move as far back or forward.

    That discovery is thanks to the fact that Little Foot retained her atlas, or the topmost cervical vertebrae between the head and neck.
    In addition to understanding more about head movements, the atlas can also share information about blood flow to the brain through vertebral arteries.

    The researchers discovered that the facets allowing for articulation between the head, first vertebra and second vertebra are more concave for Little Foot than modern humans, said Amélie Beaudet, study author and researcher at the University of the Witwatersrand in Johannesburg, South Africa.

    "These features might be useful for Australopithecus when climbing trees," Beaudet said.

    Little Foot's atlas is similar to those in modern chimpanzees, as are her ligaments. Chimpanzees spend about eight or nine hours a day in trees and sleep in nests they've built there to remain safe from predators. Australopithecus likely did the same.

    The researchers were also able to estimate blood flow to the brain, based on the skull and vertebrae. Little Foot's blood flow to the brain, and likely the use of glucose by the brain, was three times lower than modern humans. This is also similar to chimpanzees.

    "The low investment of energy into the brain of Australopithecus could be tentatively explained by a relatively small brain of the specimen, a low quality diet [low proportion of animal products] or high costs of other aspects of the biology of Australopithecus [such as upright walking]," Beaudet said. "In any case, this might suggest that the human brain's vascular system emerged much later in our history." The study published this week in the journal Scientific Reports.

    Previously, Beaudet studied the endocast of Little Foot, or the imprint of the brain preserved on the inside of the skull, along with her inner ear structure. Little Foot's inner ear provided insight not only about her hearing, but her sense of balance.

    "I could demonstrate that the shape of the inner ear was compatible with activities in the trees and the ground, which is confirmed by our new study of the atlas," Beaudet said. "Moreover, the reconstruction of the brain showed that it was three times smaller than ours and that the organization was very different from us, meaning that the emergence of a human-like brain occurred later in our history."

    Compared with younger Australopithecus skeletons, Little Foot spent more time in trees
    .
    "A southern African Australopithecus specimen [later] than 'Little Foot' [probably younger by about 1 million years] may have partially lost this capacity and spent more time on the ground, like us today," Beaudet said.
    Who was Little Foot?

    Australopithecus is thought to be our potential direct ancestor, the researchers said. Studying Little Foot provides researchers with an opportunity to look back at ancient ancestors who walked upright -- long before the rise of the first humans.

    These fossils have been found in South Africa over the years, leading to its naming as the "cradle of humankind."
    Little Foot got her name because she was first known based on the discovery of four foot bones found in 1995 by University of Witwatersrand researchers Ron Clarke and Philip Tobias. Tobias died in 2012.

    From those four bones alone, they were able to determine that the creature combined both human and ape-like traits, Beaudet said. The bones also revealed Little Foot walked on two legs.

    Most of her skeleton was found embedded in sediment of South Africa's Sterkfonetin Cave, including a complete skull. It took Clarke and his colleagues 20 years to painstakingly unearth it.

    "She may not be perfect in formed body, with some bones missing, but Little Foot is our great-great aunt many times removed and she is perfect to me," Clarke famously said when Little Foot was revealed to the world in 2017.

    Since then, Little Foot has been scanned and studied by researchers at the University of Witwatersrand, which remains her home. Beaudet began studying Little Foot in 2017.
    Multiple Australopithecus species lived in Africa around three million years ago, including anamensis, africanus and afarensis like the famed Lucy skeleton. It's possible that Little Foot belonged to the prometheus species, but it hasn't been confirmed by the researchers yet.

    "Australopithecus had a small brain, large teeth and males and females were really different from each other -- while humans have a large brain, smaller teeth and human males and females are less distinct," Beaudet said. "Australopithecus could climb trees and walk on the ground while we, humans, have lost the capacity of climbing and moving in trees like Australopithecus."

    More questions remain about Little Foot and the researchers will continue studying her unique fossil. Her crushed and deformed skull presents a challenge, so they are using scans to virtually separate and reassemble the bone fragments. This will better allow them to have a complete picture of what the Australopithecus skull looked like and compare it to others. Her hip bones will also need to be virtually reconstructed. And they can also learn more about her diet based on her teeth.

    © Copyright Original Source

    Last edited by shunyadragon; 03-21-2020 at 05:49 AM.
    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

  5. #4
    Evolution is God's ID rogue06's Avatar
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    Quote Originally Posted by shunyadragon View Post
    A new discovery about the Australopithecus show more evidence of the evolution of earlier primates and later primates that lead to human evolution. This diversity of subspecies and varieties of the widespread adaptation Australpithecus is already known that lead to the evolution of humans. The discovery shows this variation of Australpithecus lived partially in trees.

    Source: https://www.9news.com.au/world/little-foot-australopithecus-lived-in-trees-was-vegetarian-say-researchers/921c0d91-196e-4c0e-a6ba-f5bb53a7c5e8



    Ancient human ancestor probably lived in trees

    Around 3.67 million years ago, an ancient human ancestor nicknamed Little Foot fell about 30 feet down into a deep shaft of a cave. Today, she represents the most complete Australopithecus skeleton and is helping researchers to learn more about our chimpanzee-like ancestors. Little Foot likely stood over just four feet tall. She would have slept in trees to remain safe from giant predators like sabre-toothed cats. And she was likely a vegetarian who munched on plants. Little Foot had powerful hands and a special big toe that allowed for better climbing.

    This week, researchers studying her skeleton learned something new. They shared that Little Foot was capable of different head movements than modern humans. This was likely due to the fact that Little Foot spent so much time in trees and was an expert climber. Humans have lost those special abilities and don't need their heads to move as far back or forward.

    That discovery is thanks to the fact that Little Foot retained her atlas, or the topmost cervical vertebrae between the head and neck.
    In addition to understanding more about head movements, the atlas can also share information about blood flow to the brain through vertebral arteries.

    The researchers discovered that the facets allowing for articulation between the head, first vertebra and second vertebra are more concave for Little Foot than modern humans, said Amélie Beaudet, study author and researcher at the University of the Witwatersrand in Johannesburg, South Africa.

    "These features might be useful for Australopithecus when climbing trees," Beaudet said.

    Little Foot's atlas is similar to those in modern chimpanzees, as are her ligaments. Chimpanzees spend about eight or nine hours a day in trees and sleep in nests they've built there to remain safe from predators. Australopithecus likely did the same.

    The researchers were also able to estimate blood flow to the brain, based on the skull and vertebrae. Little Foot's blood flow to the brain, and likely the use of glucose by the brain, was three times lower than modern humans. This is also similar to chimpanzees.

    "The low investment of energy into the brain of Australopithecus could be tentatively explained by a relatively small brain of the specimen, a low quality diet [low proportion of animal products] or high costs of other aspects of the biology of Australopithecus [such as upright walking]," Beaudet said. "In any case, this might suggest that the human brain's vascular system emerged much later in our history." The study published this week in the journal Scientific Reports.

    Previously, Beaudet studied the endocast of Little Foot, or the imprint of the brain preserved on the inside of the skull, along with her inner ear structure. Little Foot's inner ear provided insight not only about her hearing, but her sense of balance.

    "I could demonstrate that the shape of the inner ear was compatible with activities in the trees and the ground, which is confirmed by our new study of the atlas," Beaudet said. "Moreover, the reconstruction of the brain showed that it was three times smaller than ours and that the organization was very different from us, meaning that the emergence of a human-like brain occurred later in our history."

    Compared with younger Australopithecus skeletons, Little Foot spent more time in trees
    .
    "A southern African Australopithecus specimen [later] than 'Little Foot' [probably younger by about 1 million years] may have partially lost this capacity and spent more time on the ground, like us today," Beaudet said.
    Who was Little Foot?

    Australopithecus is thought to be our potential direct ancestor, the researchers said. Studying Little Foot provides researchers with an opportunity to look back at ancient ancestors who walked upright -- long before the rise of the first humans.

    These fossils have been found in South Africa over the years, leading to its naming as the "cradle of humankind."
    Little Foot got her name because she was first known based on the discovery of four foot bones found in 1995 by University of Witwatersrand researchers Ron Clarke and Philip Tobias. Tobias died in 2012.

    From those four bones alone, they were able to determine that the creature combined both human and ape-like traits, Beaudet said. The bones also revealed Little Foot walked on two legs.

    Most of her skeleton was found embedded in sediment of South Africa's Sterkfonetin Cave, including a complete skull. It took Clarke and his colleagues 20 years to painstakingly unearth it.

    "She may not be perfect in formed body, with some bones missing, but Little Foot is our great-great aunt many times removed and she is perfect to me," Clarke famously said when Little Foot was revealed to the world in 2017.

    Since then, Little Foot has been scanned and studied by researchers at the University of Witwatersrand, which remains her home. Beaudet began studying Little Foot in 2017.
    Multiple Australopithecus species lived in Africa around three million years ago, including anamensis, africanus and afarensis like the famed Lucy skeleton. It's possible that Little Foot belonged to the prometheus species, but it hasn't been confirmed by the researchers yet.

    "Australopithecus had a small brain, large teeth and males and females were really different from each other -- while humans have a large brain, smaller teeth and human males and females are less distinct," Beaudet said. "Australopithecus could climb trees and walk on the ground while we, humans, have lost the capacity of climbing and moving in trees like Australopithecus."

    More questions remain about Little Foot and the researchers will continue studying her unique fossil. Her crushed and deformed skull presents a challenge, so they are using scans to virtually separate and reassemble the bone fragments. This will better allow them to have a complete picture of what the Australopithecus skull looked like and compare it to others. Her hip bones will also need to be virtually reconstructed. And they can also learn more about her diet based on her teeth.

    © Copyright Original Source

    Abstract:

    Source: The atlas of StW 573 and the late emergence of human-like head mobility and brain metabolism


    Functional morphology of the atlas reflects multiple aspects of an organism’s biology. More specifically, its shape indicates patterns of head mobility, while the size of its vascular foramina reflects blood flow to the brain. Anatomy and function of the early hominin atlas, and thus, its evolutionary history, are poorly documented because of a paucity of fossilized material. Meticulous excavation, cleaning and high-resolution micro-CT scanning of the StW 573 (‘Little Foot’) skull has revealed the most complete early hominin atlas yet found, having been cemented by breccia in its displaced and flipped over position on the cranial base anterolateral to the foramen magnum. Description and landmark-free morphometric analyses of the StW 573 atlas, along with other less complete hominin atlases from Sterkfontein (StW 679) and Hadar (AL 333-83), confirm the presence of an arboreal component in the positional repertoire of Australopithecus. Finally, assessment of the cross-sectional areas of the transverse foramina of the atlas and the left carotid canal in StW 573 further suggests there may have been lower metabolic costs for cerebral tissues in this hominin than have been attributed to extant humans and may support the idea that blood perfusion of these tissues increased over the course of hominin evolution.


    Source

    © Copyright Original Source



    I should also note that the entire paper is available as well at the link above for those who are interested

    I'm always still in trouble again

    "You're by far the worst poster on TWeb" and "TWeb's biggest liar" --starlight (the guy who says Stalin was a right-winger)
    "Of course, human life begins at fertilization that’s not the argument." --Tassman

  6. #5
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    Quote Originally Posted by rogue06 View Post
    Abstract:

    Source: The atlas of StW 573 and the late emergence of human-like head mobility and brain metabolism


    Functional morphology of the atlas reflects multiple aspects of an organism’s biology. More specifically, its shape indicates patterns of head mobility, while the size of its vascular foramina reflects blood flow to the brain. Anatomy and function of the early hominin atlas, and thus, its evolutionary history, are poorly documented because of a paucity of fossilized material. Meticulous excavation, cleaning and high-resolution micro-CT scanning of the StW 573 (‘Little Foot’) skull has revealed the most complete early hominin atlas yet found, having been cemented by breccia in its displaced and flipped over position on the cranial base anterolateral to the foramen magnum. Description and landmark-free morphometric analyses of the StW 573 atlas, along with other less complete hominin atlases from Sterkfontein (StW 679) and Hadar (AL 333-83), confirm the presence of an arboreal component in the positional repertoire of Australopithecus. Finally, assessment of the cross-sectional areas of the transverse foramina of the atlas and the left carotid canal in StW 573 further suggests there may have been lower metabolic costs for cerebral tissues in this hominin than have been attributed to extant humans and may support the idea that blood perfusion of these tissues increased over the course of hominin evolution.


    Source

    © Copyright Original Source



    I should also note that the entire paper is available as well at the link above for those who are interested
    Thank you for the new info. For new discoveries in science we make a reasonable tag team of information. Most may not respond, but the information speaks for itself.
    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

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