Genetic disorders, pedigree analysis - Principles of Inheritance and Evolution, Biology Video Lecture - Class 12

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how in this section we are going to talk
about the genetic disorders now as I
said there can be mutations when the
structure of insulin changes or as a
number of Thrones or changes in the
structure of chromosome gene is now as I
said mutations are not necessary
powerful odd ways but at the same time
not all these mutations are useful as
well so sometimes these kind of changes
and actually bring about this order in
an organism or an individual so this is
what we are going to talk about here
when we will see what are the ways
genetic disorders what if what are the
various disorders that can happen in
individual that happens due to genetics
are they that comes in that individuals
you can see better
now when I say genetic disorders it is a
problem or a disease that is present
from birth you can generate ignore
delicious now not all disorder is a
disease it is not necessary that
something which is a disorder this
disease that is order can be something
which is not a disease you are not
suffering from that disease but it is
just a problem is not normal it is
little different from what does not well
but it is a kind of problem right so
that is the literal meaning of disorder
many same disease this is is which you
are all aware of right so when you are
actually suffering from a disease and it
can be fatal or even if it is not fatal
so this is literally we are not exactly
the same but when they define genetic
disorder some of the disorders for a
given disease some things can't just be
a disorder just a problem but it is not
the actual affecting your life is there
but still you are able to do it will do
with that now any such problem which
exists from birth to the genetic
abnormalities now he doesn't have and
you any of the external factors it
happens because of some issues with the
gene so maybe during the process of
things it is
you see so many parking anything stay
please during the course of this process
thank so many I will be able and it
believes so many times it happens that
the sister chromatids separate so many
as the holo Scrolls they are very for
mining in the separator so many small
small things take place during this
entire event so there is always a
possibility of an error and a multi step
so whenever you have anything on these
processes so that is out of your scope
that you may not know what's happening
inside the body but sometimes it is a
natural process occur which there might
be some genetic abnormalities as a
result of which the baby which is worn
since the time of birth which we have
some problems due to those genetic
abnormalities and they are known as
genetic disorders now move you
understand why it is so important to
understood study about anything
disorders because this is something
which is not in our hands we cannot
control the way cell division is taking
place the way ble is duplicating itself
so we cannot control our this errors but
what we can do is we can try to prevent
genetic disorders how by studying about
it now if we know that okay so right now
we already know that if we know the
genetic makeup of both the parents we
can actually train it
what kind of offsprings can be produced
by this couple right so very good we
feel that okay there is a possibility
that this couple might give birth to a
kid Mike avenatti disorder it may be
some preventive measures can be taken
right so that is the purpose of studying
about who's making these orders these
kind of gently disorders keep on passing
they take at keep they keep on going
from one generation to the next
this is generation 1 this is generation
to their kids
so this couple they give go to say two
boys so they are there is then get
married and then again these are their
kids of this generation 3 she anything
they give birth to a boy they go through
girl not begging and mind and again
but still you see that something which
was present United planets in Europe so
let us talk about the genetic disorders
now in order to study how the tournament
is almost anything handed there is a
technique which is known as pedigree
analysis so this is many single table
which means study of key handles on
these orders very easy because it is not
really simple to understand it manually
okay because we cannot experiment with
you in these so let us see what this
pedigree analysis it is a technique to
study the inheritance of traits over
several generations in a family
so you actually prepare a family tree
kind of a structure where you see then
how the chains are being inherited or
how the genes are being passed on from
one generation to the other
now if you actually try to do pack a
family tree it is not that simple it is
going to be a very complex structure so
first a couple in their kids then they
get married they form a bubble then
there is so the tree keeps on expanding
right so if you want to study the
inheritance of tails you actually need a
very smart paper so that you can do it
very efficiently and for that purpose
was introduced this pre-degree analysis
now the question is why do we do this
analysis why is it so important to have
a technique just to study the
inheritance of traits over generations
we can just try to do it in a macro
level so let us try to see why is
important to have pedigree analysis to
understand traits over several
generations so let us try to understand
why do we use for my tea
why is pedigree analysis required it
will remind the possibility of an
offspring with a genetic disorder so as
I said if you study the way the traits
are being inherited from one generation
to the next family it becomes easier to
track if there is a possibility of
genetic disorder in an off state so you
can do it beforehand
someday we'll need measures can be taken
so that is one
language controlled crosses are not
possible but in case of human beings we
cannot perform controlled processes to
what do we be my controlled cross when
control cross is crossing of two
individuals of desired traits now many
things that doesn't happen like you we
cannot use human beings for
experimentation purpose like how the be
plant was used or how the fruit fly was
used so that is a little difficult in
case of human beings so we cannot
deliberately breed to individuals to
produce an offspring and that we cannot
allow we cannot choose desirable genetic
characters to be crossed to produce
offsprings just for experimentation
purpose so controlled crosses a little
difficult so that for that reason also
we have affinity analysis so that we can
prepare an analysis chart and we can
forecast the possibility of the instance
of traits to the next determination
human beings produced fewer children now
in real life
the number of children increase of human
beings and start with one end of the
families with only one children even if
there are few families in little areas
where you will see that they are
launched eventually that number doesn't
go beyond ten or fifteen if everything
is on the maximum side so with fewer
children you cannot actually conclude
something because with experimentation
you need to have more and more data only
then you can reach a conclusion but with
lesser number of children with less
number of people in the entire chart you
just cannot reach to a conclusion to
understand the whole of inheritance now
this is very very important now when we
prepare a pedigree analysis track we
actually get to see that how the
inheritance is actually taking place how
specific trait is being passed on from
one generation to the other generation
so that is also it helps to determine
whether the trait is dominant or
recessive
now if you prepare a pedigree chart you
will be able to know that tree which is
getting inherited whether it is a
dominant trait or a recessive trait now
how is it important to know this because
if you mole
that changes a dominant trait that means
even if you get it from one of your
parents you will be affected with the
disease let us suppose if if a disease
then I suppose if that trailer if the
gene which is silent a particular
disorder if that is a dominant trait
that means even if you get it from one
of your parents you might be an affected
individual but if it is a recessive
trait that is when we get disorder over
you when you get it or any we inhaled it
from boots your pants right so that
means it helps to know if the Train is a
dominant or a recessive trait so now let
us talk about the technique how exactly
do we use this technique of pedigree
analysis so before we actually talk
about the technique there are quite a
few symbols which you will use in order
to prepare the credibly track so let us
first look at the symbols the specific
symbols are used to prepare pedigree
analysis charts it is look at the symbol
son we often use a square for males so
the squared is U which for to denote a
male a circle is used to denote female
so here I am coloured then just or you
can use your whenever you see pink you
can relate it to a female egg where you
see blue you can relate it to a male so
that is just for you convenient purpose
otherwise obtained square boxes are male
and freckle is a female if you have a
triangle like this then if this means
that the sex is unspecified so we do not
know the sex of the individual whether
it is male or female so if you have
something marked in red so if it is all
red that means these individuals on the
spoons on the existence of aliens means
the sex is unspecified but if they are
all born red that means that these
individuals are affected so they are
affected with a disorder if you have
something like this what is this this is
a male this is a female and you see a
lion joining both of them so this means
that there is mating happening between
the male and the female so this denotes
mating between a male
female so you can say that this is the
hospital survived when they get married
the possibilities they've made so it is
denotes the mating what does this mean
they have double lines between the male
and the female again here businessman
this is female so the double line waters
this indicate this indicates that here
also making is happening because the
lines can eat them but this shows that
there is mating between relatives so
maybe if there the boy and the girl they
are cousin brothers and sisters maybe
they are their own brothers or sisters
so they are related so they belong to
the same family but and then they are
meeting so there this is that makes a
difference right because if both the
male and the female they belong to the
same family so they already share some
of your genetic characteristics now when
they go to mate then the result is going
to be little different then if two
individuals individuals me in that is
their genetic makeup is completely
different because their families are not
related to each other right
so wherever you have a double line that
means the painting is happening between
relatives who already belong to the same
family so what does this pink indicates
so this is a male this is a female
this slide shows that they are making
now when they made offsprings will be
reduced so that is devoted by these
lines and what are the offsprings that
tops things are this is these are the
children so these denote the children so
this is a good and this is a boy so they
are the patterns so live these are
parents and these are the offsprings now
in offspring also they are shown in the
order so from left in the order of left
to right it shows and the order of their
birth so here you choose that the girl
was born first and then the boy was born
so that isn't that border it shows so
what does this show this again shows
services the maize is the females they
get married and when they are mating and
they give birth to a meal this is a mere
child a boy who is affected so here you
see that the mean child is affected here
they give both women
we'll check what does this mean so when
you have just this box that means that
sex is unspecified but when you have
this with the number inside that means
the fine or strings have been produced
and the file options are unaffected now
we do not know whether the five walks of
strings they are doing or they are all
female or some of them are males and
some of them are females we don't have
that data but all we know is there are
five options and all them are unaffected
so these are some of the symbols which
are extensively used in physically
analysis now using this it helps because
now what if I do is you can do a
research on various data because you can
get the data from different recollection
we can actually start Bell or beliefs
and then you can analyze okay what I
know it's gang involved in this family
for this particular color thank you
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