These Mice Pups Inherited Immunity From Their Parents—But Not Through DNA
The rules of inheritance are supposedly easy. Dad’s DNA mixes with mom’s to generate a new combination. Over time, random mutations will give some individuals better adaptability to the environment. The mutations are selected through generations, and the species becomes stronger.
But what if that central dogma is only part of the picture?
A new study in Nature Immunology is ruffling feathers in that it re-contextualizes evolution. Mice infected with a non-lethal dose of bacteria, once recovered, can pass on a turbo-boosted immune system to their kids and grandkids—all without changing any DNA sequences. The trick seems to be epigenetic changes—that is, how genes are turned on or off—in their sperm. In other words, compared to millennia of evolution, there’s a faster route for a species to thrive. For any individual, it’s possible to gain survivability and adaptability in a single lifetime, and those changes can be passed on to offspring.
“We wanted to test if we could observe the inheritance of some traits to subsequent generations, let’s say independent of natural selection,” said study author Dr. Jorge Dominguez-Andres at Radboud University Nijmegen Centre.
“The existence of epigenetic heredity is of paramount biological relevance, but the extent to which it happens in mammals remains largely unknown,” said Drs. Paola de Candia at the IRCCS MultiMedica, Milan, and Giuseppe Matarese at the Treg Cell Lab, Dipartimento di Medicina Molecolare e Biotecnologie Mediche at the Università degli Studi di Napoli in Naples, who were not involved in the study. “Their work is a big conceptual leap.”
Evolution on Steroids
The paper is controversial because it builds upon Darwin’s original theory of evolution.
You know this example: giraffes don’t have long necks because they had to stretch their necks to reach higher leaves. Rather, random mutations in the DNA that codes for long necks was eventually selected, mostly because those giraffes were the ones that survived and procreated.
Yet recent studies have thrown a wrench into the long-standing dogma around how species adapt. At their root is epigenetics, a mechanism “above” DNA to regulate how our genes are expressed. It’s helpful to think of DNA as base, low-level code—ASCII in computers. To execute the code, it needs to be translated into a higher language: proteins.
Similar to a programming language, it’s possible to silence DNA with additional bits of code. It’s how our cells develop into vastly different organs and body parts—like the heart, kidneys, and brain—even though they have the same DNA. This level of control is dubbed epigenetics, or “above genetics.” One of the most common ways to silence DNA is to add a chemical group to a gene so that, like a wheel lock, the gene gets “stuck” as it’s trying make a protein. This silences the genetic code without damaging the gene itself.
These chemical markers are dotted along our genes, and represent a powerful way to control our basic biology—anything from stress to cancer to autoimmune diseases or psychiatric struggles. But unlike DNA, the chemical tags are thought to be completely wiped out in the embryo, resulting in a blank slate for the next generation to start anew.
Not so much. A now famous study showed that a famine during the winters of 1944 and 1945 altered the metabolism of kids who, at the time, were growing fetuses. The consequence was that those kids were more susceptible to obesity and diabetes, even though their genes remained unchanged. Similar studies in mice showed that fear and trauma in parents can be passed onto pups—and grandkids—making them more susceptible, whereas some types of drug abuse increased the pups’ resilience against addiction.
Long story short? DNA inheritance isn’t the only game in town.
Superpowered Immunity
The new study plays on a similar idea: that an individual’s experiences in life can change the epigenetic makeup of his or her offspring. Here, the authors focused on trained immunity—the par...
But what if that central dogma is only part of the picture?
A new study in Nature Immunology is ruffling feathers in that it re-contextualizes evolution. Mice infected with a non-lethal dose of bacteria, once recovered, can pass on a turbo-boosted immune system to their kids and grandkids—all without changing any DNA sequences. The trick seems to be epigenetic changes—that is, how genes are turned on or off—in their sperm. In other words, compared to millennia of evolution, there’s a faster route for a species to thrive. For any individual, it’s possible to gain survivability and adaptability in a single lifetime, and those changes can be passed on to offspring.
“We wanted to test if we could observe the inheritance of some traits to subsequent generations, let’s say independent of natural selection,” said study author Dr. Jorge Dominguez-Andres at Radboud University Nijmegen Centre.
“The existence of epigenetic heredity is of paramount biological relevance, but the extent to which it happens in mammals remains largely unknown,” said Drs. Paola de Candia at the IRCCS MultiMedica, Milan, and Giuseppe Matarese at the Treg Cell Lab, Dipartimento di Medicina Molecolare e Biotecnologie Mediche at the Università degli Studi di Napoli in Naples, who were not involved in the study. “Their work is a big conceptual leap.”
Evolution on Steroids
The paper is controversial because it builds upon Darwin’s original theory of evolution.
You know this example: giraffes don’t have long necks because they had to stretch their necks to reach higher leaves. Rather, random mutations in the DNA that codes for long necks was eventually selected, mostly because those giraffes were the ones that survived and procreated.
Yet recent studies have thrown a wrench into the long-standing dogma around how species adapt. At their root is epigenetics, a mechanism “above” DNA to regulate how our genes are expressed. It’s helpful to think of DNA as base, low-level code—ASCII in computers. To execute the code, it needs to be translated into a higher language: proteins.
Similar to a programming language, it’s possible to silence DNA with additional bits of code. It’s how our cells develop into vastly different organs and body parts—like the heart, kidneys, and brain—even though they have the same DNA. This level of control is dubbed epigenetics, or “above genetics.” One of the most common ways to silence DNA is to add a chemical group to a gene so that, like a wheel lock, the gene gets “stuck” as it’s trying make a protein. This silences the genetic code without damaging the gene itself.
These chemical markers are dotted along our genes, and represent a powerful way to control our basic biology—anything from stress to cancer to autoimmune diseases or psychiatric struggles. But unlike DNA, the chemical tags are thought to be completely wiped out in the embryo, resulting in a blank slate for the next generation to start anew.
Not so much. A now famous study showed that a famine during the winters of 1944 and 1945 altered the metabolism of kids who, at the time, were growing fetuses. The consequence was that those kids were more susceptible to obesity and diabetes, even though their genes remained unchanged. Similar studies in mice showed that fear and trauma in parents can be passed onto pups—and grandkids—making them more susceptible, whereas some types of drug abuse increased the pups’ resilience against addiction.
Long story short? DNA inheritance isn’t the only game in town.
Superpowered Immunity
The new study plays on a similar idea: that an individual’s experiences in life can change the epigenetic makeup of his or her offspring. Here, the authors focused on trained immunity—the par...
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