are you wondering what is mitochondrial dna and do i need to take a mitochondrial dna test
today i'm going to go over some of the basics of mitochondrial dna and whether or not a test
would be good for you howdy welcome to family histogenics where we love helping you climb
your family tree and have fun along the way if you're new to genetic genetology then chances
are you have questions well check out the link in our description below to the 5 most common
questions we are asked about dna you've probably heard about mitochondrial dna and are wondering
what it is and how it might be useful well mitochondrial dna is sometimes called the maternal
dna or the mother's dna and that is because it is passed on from mother to children let's go over
the whiteboard and let's talk a little bit about dna and what's different about mitochondrial dna
so you can understand how it might be useful in your genetic genealogy when we think about dna
mostly what we're thinking about is what is in the nucleus of our cells and so there is going to be a
pairs of chromosomes so there's one pair here's two pairs here's three pairs uh
four pairs and there's for humans there's 23 pairs i'm not going to draw them all out
now besides the dna that is in our nucleus of our cells there happens to be some dna in another part
of our cell called the mitochondria and this dna is actually a little circle so it's not a
rod or or a chromosome like we normally think of it is actually a circular portion of dna
so here's a couple of big differences that we have so this dna that's in our nucleus it is three
billion letters long three billion that's a lot whereas this mitochondrial dna is only 16 000
letters long so it is much smaller much shorter amount of dna than the rest of our
dna than any single one of our chromosomes even the shortest chromosome the chromosome number
22 is something like 40 million letters long so this mitochondrial dna is tiny really really tiny
now how or where did this dna come from well let me draw a picture of a cell this is going back to
biology and i said before that the dna that we're talking about with chromosomes number one through
23 is in the nucleus right here and i'm just going to draw a couple of lines there
to represent that dna that is in there this other dna this mitochondrial dna is in some
other parts of our cells called mitochondria and each cell has hundreds and sometimes even more
of these mitochondria they're very important to the biological process of creating energy
now what's interesting is from our study of science what has happened is about
1.5 billion years ago we had everything was just a single cell there was different cells that
you know did different things and they were all just floating around you know
doing their doing their business and in some of these cells they were really good
at making energy and what happened is that another cell went and basically enveloped that one
and brought it inside of itself and so now what you had is you had a cell within a cell and they
developed and grew like that and that is where our mitochondria came from and so that's why this
mitochondrial dna actually looks very different from the rest of the dna we have is because it was
from originally two completely different cells that joined together um to give us
what we have today now this happened before plants developed this happened before fungi developed
like i said this happened back when everything was single cellular and so every multicellular
which means plants animals fungi they have this structure this mitochondria structure because
it's all descended from these original cells that enveloped these other cells that happen
to have this process that they were really good at so that is the biology lesson that we have
for today how then does mitochondrial get passed on well in the sex cells of humans there are eggs
and sperm the mothers have the eggs and the fathers have the sperm all that the
fathers contribute to the child in the end it really is just their nuclear material
they don't contribute all the rest of the part of the cell and so this cell that we have here
is combined with the mother cell and a little bit of the father's dna
and that's why mitochondrial dna is passed down from mother to children because every single one
of these mitochondria came from the mother none of them came from the father now the second part
of that question then is is should you take a mitochondrial dna test the answer to that is it
depends do you have a dna question that could be answered recognizing that mitochondrial dna
is passed from mother to children if the question is on some other part of your
tree then a mitochondrial dna test is not going to help you out two other things complicate whether a
mitochondrial dna test is going to help you with your genealogy one is is that traditionally the
females took on the male names and so there's not a surname that you can really attach to any
of these mitochondrial lines you have to know each one of those individuals
you know throughout that line the second thing is is that again mitochondrial is only 16 000 letters
long and not all of those letters are different there's there's uh only a couple hundred of them
that are going to be different for you know all the different people in the world and that means
that those changes happen over thousands of years they don't happen rapidly at all so even
if you do have a mitochondrial dna match that person may be hundreds or thousands of years
related to you before you have a common ancestor which is beyond where
most genealogical records are from and so the advice that i normally give people is if you
have exhausted everything from autosomal dna and if you have exhausted all of your different
genealogical research as far as paper genealogy records and different things like that
and if you have the money then go ahead and get a mitochondrial dna test but recognize that
it's probably not going to answer the question that doesn't mean it will never
answer the question just that it probably will not answer the question mitochondrial dna tests are
primarily done at family tree dna and they cost a couple hundred dollars
so again unless you have the money and unless you've exhausted your other resources there's
probably not a reason to get a mitochondrial dna test now i've had a mitochondrial dna test
but it really was just for learning to be able to show different things on this channel i have never
used my mitochondrial dna test for any kind of genealogy research and i don't expect to
if you still have questions about dna then join us in our dna live streams where we answer your
questions and consider joining fhf extra where we have even more dna q a sessions as well as
webinars now if you would like to learn more about other types of dna i have this video up here but
if there's something else you want to learn then why don't you try looking at this video down below
i'm losing my voice hopefully i can get through all of these