mitochondrial DNA

THC

Very interesting stuff...

what do people on here know about it?

seems to be opening up a lot of scientific discussion.....

Ahnimus

I have to admit, biology is one of my weaker links. I have two friends with biology textbooks, I'm gonna steal one after I finish Gray's Pscyhology. I didn't think mitochondria was a type of DNA, I thought it was a feature of some cell bodies, is that the reference?

chopitdown

Ahnimus wrote:

I have to admit, biology is one of my weaker links. I have two friends with biology textbooks, I'm gonna steal one after I finish Gray's Pscyhology. I didn't think mitochondria was a type of DNA, I thought it was a feature of some cell bodies, is that the reference?

mitochondria have dna (hence mitochondralDNA) since they are a living cell / organism. that's all I've got

Ahnimus

chopitdown wrote:

mitochondria have dna (hence mitochondralDNA) since they are a living cell / organism. that's all I've got

I've heard it a billion times in those HHMI lectures. But, I didn't retain it, I'm mostly interested in nerve cells and synapses though.

Here is an article from HHMI http://www.hhmi.org/bulletin/may2006/pdf/Mitochondria.pdf

The Powerhouse of the Cell

chopitdown

Ahnimus wrote:

I've heard it a billion times in those HHMI lectures. But, I didn't retain it, I'm mostly interested in nerve cells and synapses though.

Here is an article from HHMI http://www.hhmi.org/bulletin/may2006/pdf/Mitochondria.pdf

The Powerhouse of the Cell

i should have said that's all i've got in regards to mitochondralDNA. I've got a basic understanding of mitochondria; and I'm happy to keep it at a basic understanding

Ahnimus

chopitdown wrote:

i should have said that's all i've got in regards to mitochondralDNA. I've got a basic understanding of mitochondria; and I'm happy to keep it at a basic understanding

It's hard to find something on it exactly

Luis Brieba de Castro, a newly named HHMI international research scholar, is working to understand how the DNA that is found outside the nucleus of cells produces proteins. That DNA, called mitochondrial DNA, is found in small cellular structures called mitochondria. Mutations in mitochondrial DNA have been linked to several inherited medical conditions, including some forms of hearing and vision loss.


Scientists know that mitochondrial DNA is inherited only from the mother, but they do not yet fully understand the basic mechanisms of nucleic acid metabolism and how DNA damage is linked to diseases. Brieba de Castro hopes to find answers that could lead to genetic interventions to correct certain inherited disorders. Following previous studies of DNA replication in bacteriophage, a type of virus that infects bacteria, he is working in the yeast Saccharomyces cerevisiae to explore how DNA functions in the mitochondria.

http://www.hhmi.org/news/20061101a.html

There is also something about tracing our ancestry through it.

THC

Ahnimus wrote:

There is also something about tracing our ancestry through it.

the stuff about tracing ancestry is the really cool part. i saw a bit on this on 20/20 the other day. Its interesting though...one of their points was that if you go back say 8 generations...of your own DNA...you'd have something like 24,000 grandparents or something crazy. Which means...our genes..are very much a combination of many...many gene pools...from all over the globe.

Ahnimus

THC wrote:

the stuff about tracing ancestry is the really cool part. i saw a bit on this on 20/20 the other day. Its interesting though...one of their points was that if you go back say 8 generations...of your own DNA...you'd have something like 24,000 grandparents or something crazy. Which means...our genes..are very much a combination of many...many gene pools...from all over the globe.

So the redneck claim "My mother's my sister" isn't too far off

Doesn't evolution suggest that all species share a common ancestry?

Lucy I'm home!!! mmmm Australopithecusafarensis!

Wait, how many days did it take God to create the universe?

tybird

Ahnimus wrote:

So the redneck claim "My mother's my sister" isn't too far off

Doesn't evolution suggest that all species share a common ancestry?

No, it's my wife is my sister...silly.

Yes, according to evolution, we all share a distant (very distant as in a long time ago) common ancestor.

MahoganySouls

tybird wrote:

No, it's my wife is my sister...silly.

Yes, according to evolution, we all share a distant (very distant as in a long time ago) common ancestor.

I wonder if his name is Adam.

Bwalker545

Mitochondrial Eve http://en.wikipedia.org/wiki/Mitochondrial_eve
Y Chromosomal Adam http://en.wikipedia.org/wiki/Y-chromosomal_Adam

luvisatower

chopitdown wrote:

mitochondria have dna (hence mitochondralDNA) since they are a living cell / organism. that's all I've got

Mitochondria are NOT organisms/cells. Mitochondria are organelles within cells, they produce energy in the form of ATP to power the cell's activities.
Mitochondria have their own DNA, it is circular in arrangement and similar to that in prokaryotes (bacteria).. It is thought that eukaryotic cells arose from an endosymbiotic relationship between mitochondria and other prokaryotic cells.
There is a distinct evolutionary connection between mitochondrial DNA across species. Additionaly, it is beleived that all human mitochondrial DNA is passed from mother to offspring since egg cells have mitochondria and sperm do not and that all mitochondrial DNA originated from a single female known as mitochondrial Eve.

Anything else you'd like to know?
Just ask
Peace,
luv

Vedd Hedd

luvistower wrote:

Mitochondria are NOT organisms/cells. Mitochondria are organelles within cells, they produce energy in the form of ATP to power the cell's activities.
Mitochondria have their own DNA, it is circular in arrangement and similar to that in prokaryotes (bacteria).. It is thought that eukaryotic cells arose from an endosymbiotic relationship between mitochondria and other prokaryotic cells.
There is a distinct evolutionary connection between mitochondrial DNA across species. Additionaly, it is beleived that all human mitochondrial DNA is passed from mother to offspring since egg cells have mitochondria and sperm do not and that all mitochondrial DNA originated from a single female known as mitochondrial Eve.

Anything else you'd like to know?
Just ask
Peace,
luv

I was going to point this out....well, SOME of it anyway.:D

Especially your first sentence.

Scubascott

What luvistower said. The theory of aquisition of organelles by endocytosis has been around for a long time now. The chloroplasts found in plant cells also thought to be decended from prokaryotic symbionts. There are other ineteresting examples of intracellular symbionts living in eukaryotic cells that look like they might be headed down the path of evolving into organelles. Some corals, for example, harbour nitrogen fixing bacteria inside their cells.

The important thing about mitochondiral DNA from out point of view is the way in which it is inherited. We're all taught that our DNA is 50% from our father and 50% from our mother, but that's not exactly true. We get all our mitochondrial DNA from our mothers, because sperm do not contribute any mitochondria when the egg is fertilised. This has applications in forensics etc as well, as mitochnidrial DNA can be used to trace maternal lines. I've noticed that they also like to throw the term 'mitochondrial DNA' randomly into lab scenes on crap shows like CSI and law and order.

Ahnimus

So, what do you call the DNA from the cell body that isn't mitochondrial DNA, is it cellular DNA?

That is 50/50 mother/father, correct?

Endocytosis, that is the process whereby a cell membrane absorbs molecules? As in when neurotransmitters are released by the presynaptic cell and absorbed into the receptors of the postsynaptic cell, the process is endocytosis, correct?

Jeanie

Scubascott wrote:

What luvistower said. The theory of aquisition of organelles by endocytosis has been around for a long time now. The chloroplasts found in plant cells also thought to be decended from prokaryotic symbionts. There are other ineteresting examples of intracellular symbionts living in eukaryotic cells that look like they might be headed down the path of evolving into organelles. Some corals, for example, harbour nitrogen fixing bacteria inside their cells.

The important thing about mitochondiral DNA from out point of view is the way in which it is inherited. We're all taught that our DNA is 50% from our father and 50% from our mother, but that's not exactly true. We get all our mitochondrial DNA from our mothers, because sperm do not contribute any mitochondria when the egg is fertilised. This has applications in forensics etc as well, as mitochnidrial DNA can be used to trace maternal lines. I've noticed that they also like to throw the term 'mitochondrial DNA' randomly into lab scenes on crap shows like CSI and law and order.

Hey!! Don't be picking on Grissom!

That all sounds very interesting Scott and well explained coz even I managed to wrap my head around it.

Aren't mitochondrial dna the little swirly strands?

Scubascott

Heh. All DNA is 'little swirly strands'. The point here is what part of the cell those strands are found in.

Basically there are two types of cellular organisms on earth - prokaryotic - which are bacteria and archaea. Simple single celled organisms. Very small, with no real structures inside their cells. Basically everything (DNA, proteins, and other molecules) floats around inside the outer cell membrane.

The second type are called eukaryotes. This includes all the higher forms of life, including plants, animals and fungi. Eukaryotic cells (like ours) have structures inside them with their own little membranes, like tiny cells within a cell. These structures are called organelles. The defining ones are the nucleus, which contains most of the DNA, and other things like mitochondria, chloroplasts (only in plants) etc. Some of these organelles have their own DNA. The DNA contained in the nucleus is what you inherit in a 50/50 ratio from your parents. There are two copies of each one of your chromosomes in that nucleus. You get one copy from your mother (these are the ones that were present in the egg cell before fertilisation) and one copy from your father (from the sperm). But since the sperm does not contribute any organelles, the DNA in your mitochondria all comes from your mother.

That's biology 101 for today. I have to go. More later if people are interested.

Jeanie

Scubascott wrote:

Heh. All DNA is 'little swirly strands'. The point here is what part of the cell those strands are found in.

Basically there are two types of cellular organisms on earth - prokaryotic - which are bacteria and archaea. Simple single celled organisms. Very small, with no real structures inside their cells. Basically everything (DNA, proteins, and other molecules) floats around inside the outer cell membrane.

The second type are called eukaryotes. This includes all the higher forms of life, including plants, animals and fungi. Eukaryotic cells (like ours) have structures inside them with their own little membranes, like tiny cells within a cell. These structures are called organelles. The defining ones are the nucleus, which contains most of the DNA, and other things like mitochondria, chloroplasts (only in plants) etc. Some of these organelles have their own DNA. The DNA contained in the nucleus is what you inherit in a 50/50 ratio from your parents. There are two copies of each one of your chromosomes in that nucleus. You get one copy from your mother (these are the ones that were present in the egg cell before fertilisation) and one copy from your father (from the sperm). But since the sperm does not contribute any organelles, the DNA in your mitochondria all comes from your mother.

That's biology 101 for today. I have to go. More later if people are interested.

I'll have to read that several times for it to sink in, but then I have read basically that so many times and it never really sinks in. Mind of a fish! :rolleyes:

Ok so now I have a really dumb question, well the question may not be dumb but my execution of it probably will be.
My understanding of stem cells is that they can make them or are attempting to make them without that bit in the middle that decides what kind of cell they are in order to make them specifically as the kind of cell that they want. Does that mean that the mytochondria and all the other things in the nucleus like the chromosomes would remain? In which case, by having stem cell therapy you would potentially be recieving some one elses DNA? That probably made no sense at all.

baraka

Subascott, you might the only one interested in this. Seemed to open up a can of worms at the time, although I haven't kept up with the research. There was a great paper in The Scientist about this a few years ago, but I'm too tired to sift through the archives. Very interesting............................

http://www.nytimes.com/library/national/science/012500sci-mitochondrial-dna.html

Ahnimus

Jeanie wrote:

I'll have to read that several times for it to sink in, but then I have read basically that so many times and it never really sinks in. Mind of a fish! :rolleyes:

Ok so now I have a really dumb question, well the question may not be dumb but my execution of it probably will be.
My understanding of stem cells is that they can make them or are attempting to make them without that bit in the middle that decides what kind of cell they are in order to make them specifically as the kind of cell that they want. Does that mean that the mytochondria and all the other things in the nucleus like the chromosomes would remain? In which case, by having stem cell therapy you would potentially be recieving some one elses DNA? That probably made no sense at all.

I'm pretty sure they replace the nuclear DNA with your own. That was my understanding of how stem cells are created. They incubate an ovary with your DNA instead of the original. The differentiation of stem cells occurs depending on the types of neighbouring cells. Kind of like the way any gene is expressed. The gene doesn't contain an instruction set, but rather it's more complicated. I know that the 'master gene' for a mouse eye can be transmutated into a drosophila (fruit fly) and the drosophila will grow a drosophila eye, instead of a mouse eye, and vise-verca. So the expression of the genes depends on things besides the gene it's self.

But I'm curios to know the answer to your question about mitochondrial DNA as well. And Scott can correct me on the rest if I'm wrong.

beachdweller

in the immortal words of Jon Stewart "Go Onnnnnnn!"