I think that nowadays "gene" refers only to a subset of a nucleic acid. Sequences of ACTG (or ACUG in the case of RNA) only, and only in that organism's chromosomes.
If you inherit a virus from your mother, for instance, I think most would call that non-genetic inheritance, even though viruses have genes too. Same goes for methyl and acetyl markers, transcription factors, nutrients, toxins, and whatever else comes along for the ride in the meiotic cell.
Back in the day when they didn't know which cellular chemical was responsible for the majority of heritability I think the usage was indeed more general. But now we have "the central dogma of biology" which puts nucleic acids on a pedestal. Convenient to have rules so you can keep track of their many exceptions.
Could you restate this? I believe "genetic" usually refers to only the sequence of linear bases, while epigenetics refers to histone acetylation, and base methylation (And other things perhaps). These are also heritable, and regulate protein expression in a way that, like genetics, affects phenotype.
But there might be other ways that some traits get inherited, eg by changing the cellular environment in the sperm/egg itself which could affect the offspring while keeping the genes the same.
Maybe he's trying to go to the earliest idea of "gen-es" aka the reasons for the traits of an individual. The idea existed before the discovery of cells kernels and DNA right ? so in a way, if there are other mechanisms involved in passing traits to children, it could be termed as gen-something
Yes, that depends on the definition. Lamarck could fit into it, but he had no clue about DNA, genes and so forth; neither had Darwin. He babbled about gemmulae.
Even the definition of a gene is not very accurate. Many important sequences yield a miRNA or another RNA. Only few sequences yield a mRNA. Some "genes" are just integrated viruses/phages/transposons etc... that were modified. One of the most fascinating one was the retrovirus in regards to the mammalian placenta: https://pmc.ncbi.nlm.nih.gov/articles/PMC4332834/ but there are many more examples. We are all DNA hybrids at the end of the day. The whole species concepts makes very little sense these days, IMO. I can see the use case for eukaryotes, but it makes no sense to me for bacteria yet alone viruses.
Epigenetic inheritance is a mechanism whereby traits could be passed from one generation to the next without modifying the underlying genetic DNA. The mechanism would alter the expression of different parts of DNA.
It’s a very young field with a lot of open questions. The concept has been adopted and abused in the mainstream so you have to be careful to separate the science from the pseudoscience.
That depends on the definition. But, if we use the modern definition, it emerged (or re-emerged) in the 1990s. It's not old, indeed, but I also would no longer call it "very young". It's soon 40 years in the modern definition, and much older if we include prior discussions.
I think that nowadays "gene" refers only to a subset of a nucleic acid. Sequences of ACTG (or ACUG in the case of RNA) only, and only in that organism's chromosomes.
If you inherit a virus from your mother, for instance, I think most would call that non-genetic inheritance, even though viruses have genes too. Same goes for methyl and acetyl markers, transcription factors, nutrients, toxins, and whatever else comes along for the ride in the meiotic cell.
Got it. I had thought that actual genes were only a part of what was considered "genetics."
Back in the day when they didn't know which cellular chemical was responsible for the majority of heritability I think the usage was indeed more general. But now we have "the central dogma of biology" which puts nucleic acids on a pedestal. Convenient to have rules so you can keep track of their many exceptions.
Could you restate this? I believe "genetic" usually refers to only the sequence of linear bases, while epigenetics refers to histone acetylation, and base methylation (And other things perhaps). These are also heritable, and regulate protein expression in a way that, like genetics, affects phenotype.
No. If the change happens without altering the DNA (or RNA) sequence it's not genetic it's epigenetic.
epi- = outside
It’s not a tautology. Check out the work of Michael Levin (easily accessible on YouTube) for examples of non-genetic heritability.
Genetic would mean that genes get modified.
But there might be other ways that some traits get inherited, eg by changing the cellular environment in the sperm/egg itself which could affect the offspring while keeping the genes the same.
Maybe he's trying to go to the earliest idea of "gen-es" aka the reasons for the traits of an individual. The idea existed before the discovery of cells kernels and DNA right ? so in a way, if there are other mechanisms involved in passing traits to children, it could be termed as gen-something
Yes, that depends on the definition. Lamarck could fit into it, but he had no clue about DNA, genes and so forth; neither had Darwin. He babbled about gemmulae.
Even the definition of a gene is not very accurate. Many important sequences yield a miRNA or another RNA. Only few sequences yield a mRNA. Some "genes" are just integrated viruses/phages/transposons etc... that were modified. One of the most fascinating one was the retrovirus in regards to the mammalian placenta: https://pmc.ncbi.nlm.nih.gov/articles/PMC4332834/ but there are many more examples. We are all DNA hybrids at the end of the day. The whole species concepts makes very little sense these days, IMO. I can see the use case for eukaryotes, but it makes no sense to me for bacteria yet alone viruses.
Epigenetic inheritance is a mechanism whereby traits could be passed from one generation to the next without modifying the underlying genetic DNA. The mechanism would alter the expression of different parts of DNA.
It’s a very young field with a lot of open questions. The concept has been adopted and abused in the mainstream so you have to be careful to separate the science from the pseudoscience.
> It’s a very young field
https://en.wikipedia.org/wiki/Epigenetics#Definitions
That depends on the definition. But, if we use the modern definition, it emerged (or re-emerged) in the 1990s. It's not old, indeed, but I also would no longer call it "very young". It's soon 40 years in the modern definition, and much older if we include prior discussions.
A young field can be immature, regardless of age.
E.g., I would regard computer science as a very young field.