Mitochondrial DNA: Origin, Inheritance & Comparison

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Discussion Overview

The discussion revolves around mitochondrial DNA (mtDNA), its origins, inheritance patterns, and comparisons with nuclear DNA. Participants explore questions related to the identification of individuals based on mtDNA and nuclear DNA, as well as the broader implications of mtDNA in evolutionary biology.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants inquire whether mtDNA extracted from different body parts (e.g., toe and hair) can be used to confirm they come from the same individual, suggesting that mtDNA should be identical across locations.
  • Others clarify that while mtDNA from the same individual should be identical, it cannot uniquely identify the individual due to maternal inheritance patterns.
  • There is a question about whether mtDNA from a newborn is essentially cloned from the mother, with some participants affirming this idea.
  • Participants discuss the ability to distinguish human mtDNA from that of non-primate mammals, with some asserting that enough mutations have accumulated to allow for differentiation.
  • One participant seeks clarification on whether mtDNA and nuclear DNA can be used together to identify an individual, leading to a response that indicates no predictive relationship exists between the two types of DNA.
  • A separate line of inquiry touches on the historical context of DNA terminology and its presence in organisms without nuclei, such as bacteria.

Areas of Agreement / Disagreement

Participants generally agree on the identity of mtDNA across different body parts of the same individual and the maternal inheritance of mtDNA. However, there is disagreement regarding the predictive relationship between mtDNA and nuclear DNA, with some asserting that no such relationship exists.

Contextual Notes

Participants express uncertainty about the implications of mtDNA and nuclear DNA comparisons, particularly regarding identification and inheritance. There are also limitations in understanding the historical context of DNA terminology.

Who May Find This Useful

This discussion may be of interest to those studying genetics, evolutionary biology, or the historical development of biological terminology.

Stephanus
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Dear PF Forum,
I've seen the term mitochondrial DNA, several years ago usually in determining human migration. Never paid much attention. And recently I read that mitochondria is endosymbiosis, which is surprise me if not intriguing.
While I thought only chloroplast is endosymbiotic.

Perhaps anyone can fullfil my curiosity.

https://en.wikipedia.org/wiki/Mitochondrial_DNA#Origin
Nuclear and mitochondrial DNA are thought to be of separate evolutionary origin
1. So, if we extract the usual human DNA (perhaps from nucleus?) from toe and from hair, can we tell it comes from the same person? I think we can, unless for some chimera cases.
2. If we extract mitochondrial DNA from toe and the usual DNA from hair, can we tell that those two DNA strain come from the same individual?

and
https://en.wikipedia.org/wiki/Mitochondrial_DNA#Female_inheritance
In sexual reproduction, mitochondria are normally inherited exclusively from the mother...
https://en.wikipedia.org/wiki/Mitochondrial_DNA
Since mtDNA evolves relatively slowly compared to other genetic markers...
3. So can we say that the mitochondrial from a newborn is almost cloned from the mother?

4. And lastly, can we tell human mitochondrial DNA from another mammals not primate, say tiger?

Thank you very much.
 
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Stephanus said:
1. So, if we extract the usual human DNA (perhaps from nucleus?) from toe and from hair, can we tell it comes from the same person? I think we can, unless for some chimera cases.
Yes.

2. If we extract mitochondrial DNA from toe and the usual DNA from hair, can we tell that those two DNA strain come from the same individual?
Yes, the mitochondrial DNA extracted from two locations on the same individual should be identical. This method, however, cannot uniquely identify the individual as that individuals mother (and maternal grandmother, etc.) will all have nearly identical mitochondrial DNA sequences.

3. So can we say that the mitochondrial from a newborn is almost cloned from the mother?
Yes.

4. And lastly, can we tell human mitochondrial DNA from another mammals not primate, say tiger?
Yes. Humans and diverged from other primate and non-primate species a long enough time ago for their mitochondrial DNA to accumulate enough mutations for them to be distinguishable.
 
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Wow, thanks @Ygggdrasil for your invaluable help.
Though, I think I want a clarification of this one question
Ygggdrasil said:
Stephanus said:
2. If we extract mitochondrial DNA from toe and the usual DNA from hair, can we tell that those two DNA strain come from the same individual?
Yes, the mitochondrial DNA extracted from two locations on the same individual should be identical. This method, however, cannot uniquely identify the individual as that individuals mother...
Yes, I think mtDNA extracted from two locations on the same individual should be identical, but what I'd like to know actually, can we tell the mtDNA extracted from our toe and the nucleus DNA extracted from our hair come from the same individual?

Thanks.
 
Stephanus said:
Yes, I think mtDNA extracted from two locations on the same individual should be identical, but what I'd like to know actually, can we tell the mtDNA extracted from our toe and the nucleus DNA extracted from our hair come from the same individual?

Ah, I see. The answer to this is no. There would be no way to predict an individuals mtDNA from their genomic DNA or vice versa.
 
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Ygggdrasil said:
Ah, I see. The answer to this is no. There would be no way to predict an individuals mtDNA from their genomic DNA or vice versa.
Thank you very much. This helps me so much in reading other articles.
 
Can I ask again, perhaps off topics?
So, there are DNAs, deoxyribonucleic acid in mitochondrial aside in cell nucleus.
Adenine: C5H5N5
Thymine: C5H5N2O2
Cytosine: C4H4N3O
Guanine: C5H4N50
https://en.wikipedia.org/wiki/Arecibo_message#Nucleotides
I learn DNA formula from astronomy.
So, deoxyribonucleic acid doesn't necesseraly have to be in cell nucleus. It only refers to these pairs of sugar, right? And scientist coined the term DNA, because the first time they found these pairs of sugar was in cell nucleus?
 
Yes. Many names in biology are purely historical. Deoxyribonucleic acids are not found only in the nucleus. In fact, you will find nucleic acids even in organisms that have no nucleus like bacteria.
 
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