Jan 12, 2025 11:05 AM
We are all mosaics: riddled with genomic errors accumulating through a lifetime
https://knowablemagazine.org/content/art...ics-clones
INTRO: “That process of accumulating errors across your genome goes on throughout life,” says Phil H. Jones, a cancer biologist at the Wellcome Sanger Institute in Hinxton, England.
Scientists have long known that DNA-copying systems make the occasional blunder — that’s how cancers often start — but only in recent years has technology been sensitive enough to catalog every genetic booboo. And it’s revealed we’re riddled with errors. Every human being is a vast mosaic of cells that are mostly identical, but different here or there, from one cell or group of cells to the next.
Cellular genomes might differ by a single genetic letter in one spot, by a larger lost chromosome chunk in another. By middle age, each body cell probably has about a thousand genetic typos, estimates Michael Lodato, a molecular biologist at the University of Massachusetts Chan Medical School in Worcester.
These mutations — whether in blood, skin or brain — rack up even though the cell’s DNA-copying machinery is exceptionally accurate, and even though cells possess excellent repair mechanisms. Since the adult body contains around 30 trillion cells, with some 4 million of them dividing every second, even rare mistakes build up over time. (Errors are far fewer in cells that give rise to eggs and sperm; the body appears to expend more effort and energy in keeping mutations out of reproductive tissues so that pristine DNA is passed to future generations.)
“The minor miracle is, we all keep going so well,” Jones says.
Scientists are still in the earliest stages of investigating the causes and consequences of these mutations. The National Institutes of Health is investing $140 million to catalog them, on top of tens of millions spent by the National Institute of Mental Health to study mutations in the brain. Though many changes are probably harmless, some have implications for cancers and for neurological diseases. More fundamentally, some researchers suspect that a lifetime’s worth of random genomic mistakes might underlie much of the aging process.
“We’ve known about this for less than a decade, and it’s like discovering a new continent,” says Jones. “We haven’t even scratched the surface of what this all means.” (MORE - details)
Bigmouth buffalo: The mysterious fish that live for a century and don't decline with age
https://www.bbc.com/future/article/20250...e-with-age
INTRO: Recent findings show bigmouth buffalo fish have perplexingly long lives and appear to get healthier as they age. But scientists are worried their population is about to crash.
If you ever find yourself on the shores of Minnesota's Rice Lake in May time, you may be able to spot swarms of large fish bodies mingling among the wild rice plants in water barely a few feet deep. These are bigmouth buffalo fish, and they are the world's longest-lived freshwater fish. Some live for over 100 years.
Every year, these huge fish – which can weigh more than 50lb (23kg) – traverse through Rice River to spawn and reproduce in the lake. But the regularity of this spawning belies a hidden conservation concern: for more than six decades now, no new generations of young fish here have made it to adulthood.
Bigmouth buffalo have remained understudied for decades. In the last few years, however, scientists have begun to realise how unique these huge and incredibly long-lived fish truly are – even as they also uncover how imperilled they may be.
Bigmouth buffalo fish are native to North America and can be found from Southern Saskatchewan and Manitoba in Canada all the way down to Louisiana and Texas in the US. They're often viewed by the public and anglers as "rough fish" – a long-lived but non-scientific term used to imply that they're not particularly desirable – since they're not commercially fished and therefore not economically important.
It's this view of bigmouth buffalo that has long led them to be overlooked by scientists. Over the last five years, however, researchers have made a spate of new and surprising discoveries about them.
For one thing, individuals have been documented to reach up to 127 years of age, making them the world's longest-lived freshwater fish. They also don't seem to decline biologically with age. Most recently, researchers have realised that their stable population sizes over recent decades could be thanks to the fact that these old fish are not dying, even as they fail to produce young that survive into adulthood.
The few experts who study these fish worry that a severe drop in their population may be imminent, if not unavoidable. What's clear from the research so far is just how little we know about bigmouth buffalo, and how many unanswered questions remain.
Lackmann led the research, published in a 2019 paper, which first discovered the centenarian lifespan of bigmouth buffalo in Minnesota... (MORE - details)
https://knowablemagazine.org/content/art...ics-clones
INTRO: “That process of accumulating errors across your genome goes on throughout life,” says Phil H. Jones, a cancer biologist at the Wellcome Sanger Institute in Hinxton, England.
Scientists have long known that DNA-copying systems make the occasional blunder — that’s how cancers often start — but only in recent years has technology been sensitive enough to catalog every genetic booboo. And it’s revealed we’re riddled with errors. Every human being is a vast mosaic of cells that are mostly identical, but different here or there, from one cell or group of cells to the next.
Cellular genomes might differ by a single genetic letter in one spot, by a larger lost chromosome chunk in another. By middle age, each body cell probably has about a thousand genetic typos, estimates Michael Lodato, a molecular biologist at the University of Massachusetts Chan Medical School in Worcester.
These mutations — whether in blood, skin or brain — rack up even though the cell’s DNA-copying machinery is exceptionally accurate, and even though cells possess excellent repair mechanisms. Since the adult body contains around 30 trillion cells, with some 4 million of them dividing every second, even rare mistakes build up over time. (Errors are far fewer in cells that give rise to eggs and sperm; the body appears to expend more effort and energy in keeping mutations out of reproductive tissues so that pristine DNA is passed to future generations.)
“The minor miracle is, we all keep going so well,” Jones says.
Scientists are still in the earliest stages of investigating the causes and consequences of these mutations. The National Institutes of Health is investing $140 million to catalog them, on top of tens of millions spent by the National Institute of Mental Health to study mutations in the brain. Though many changes are probably harmless, some have implications for cancers and for neurological diseases. More fundamentally, some researchers suspect that a lifetime’s worth of random genomic mistakes might underlie much of the aging process.
“We’ve known about this for less than a decade, and it’s like discovering a new continent,” says Jones. “We haven’t even scratched the surface of what this all means.” (MORE - details)
Bigmouth buffalo: The mysterious fish that live for a century and don't decline with age
https://www.bbc.com/future/article/20250...e-with-age
INTRO: Recent findings show bigmouth buffalo fish have perplexingly long lives and appear to get healthier as they age. But scientists are worried their population is about to crash.
If you ever find yourself on the shores of Minnesota's Rice Lake in May time, you may be able to spot swarms of large fish bodies mingling among the wild rice plants in water barely a few feet deep. These are bigmouth buffalo fish, and they are the world's longest-lived freshwater fish. Some live for over 100 years.
Every year, these huge fish – which can weigh more than 50lb (23kg) – traverse through Rice River to spawn and reproduce in the lake. But the regularity of this spawning belies a hidden conservation concern: for more than six decades now, no new generations of young fish here have made it to adulthood.
Bigmouth buffalo have remained understudied for decades. In the last few years, however, scientists have begun to realise how unique these huge and incredibly long-lived fish truly are – even as they also uncover how imperilled they may be.
Bigmouth buffalo fish are native to North America and can be found from Southern Saskatchewan and Manitoba in Canada all the way down to Louisiana and Texas in the US. They're often viewed by the public and anglers as "rough fish" – a long-lived but non-scientific term used to imply that they're not particularly desirable – since they're not commercially fished and therefore not economically important.
It's this view of bigmouth buffalo that has long led them to be overlooked by scientists. Over the last five years, however, researchers have made a spate of new and surprising discoveries about them.
For one thing, individuals have been documented to reach up to 127 years of age, making them the world's longest-lived freshwater fish. They also don't seem to decline biologically with age. Most recently, researchers have realised that their stable population sizes over recent decades could be thanks to the fact that these old fish are not dying, even as they fail to produce young that survive into adulthood.
The few experts who study these fish worry that a severe drop in their population may be imminent, if not unavoidable. What's clear from the research so far is just how little we know about bigmouth buffalo, and how many unanswered questions remain.
Lackmann led the research, published in a 2019 paper, which first discovered the centenarian lifespan of bigmouth buffalo in Minnesota... (MORE - details)