EASY TO UNDERSTAND | INTRO TO GENETICS
Summary
TLDRIn this introductory genetics video, Miss Angler explains the basics of DNA and its role in determining physical traits. She clarifies the difference between genes and alleles, emphasizing that genes are inherited in pairs, with one allele from each parent. The video delves into dominant and recessive alleles, illustrating how they combine to affect an individual's phenotype. Miss Angler also discusses the process of meiosis, highlighting how alleles are passed on to offspring, and concludes with a terminology recap to aid in understanding the concepts presented.
Takeaways
- π The video is an introduction to genetics for grade 8 to 12 biology students.
- π Viewers are encouraged to like, subscribe, and turn on notifications for regular updates.
- π Miss Angler offers a membership on her YouTube page with exclusive perks like live lessons and Q&A sessions.
- 𧬠Genetics is the study of heredity and variation in living organisms, focusing on DNA and its structure.
- π§¬π§¬ Chromosomes are condensed pieces of DNA, with humans having 46 chromosomes in total.
- π DNA contains genes, which are sections that code for specific traits like height, eye color, and blood group.
- π Alleles are variations of genes, such as different eye colors, and they determine the physical expression of traits.
- π Dominant alleles are represented by uppercase letters and are expressed physically, while recessive alleles are lowercase.
- πΆ Each person inherits one maternal and one paternal chromosome, resulting in two alleles for each gene.
- π§¬π During meiosis, homologous chromosomes separate, ensuring offspring inherit one allele from each parent.
- πΌ Phenotype refers to the physical expression of traits, influenced by the combination of dominant and recessive alleles.
- π Genotype is the genetic makeup, described using uppercase for dominant and lowercase for recessive alleles in pairs.
Q & A
What is the main topic of the video?
-The main topic of the video is an introduction to genetics.
What should viewers do if they are new to Miss Angler's biology class?
-If viewers are new, they should give the video a thumbs up, like it, subscribe, turn on notifications, and consider signing up for her membership on her YouTube page.
What types of perks are offered for being a member on Miss Angler's YouTube page?
-Membership perks include exclusive videos, live lessons with Miss Angler, and question and answer sessions.
What are the basics covered in the video on genetics?
-The basics covered include the chromatin network, chromosomes, DNA, genes, alleles, and the inheritance of these genetic components.
How many chromosomes do humans have?
-Humans have 46 chromosomes.
What is the difference between a gene and an allele?
-A gene is a section of DNA that codes for a specific characteristic, while an allele is a variation of that gene, such as different eye colors.
What are homologous chromosomes?
-Homologous chromosomes are pairs of chromosomes, one inherited from each parent, that carry alleles for the same genes.
How does the process of meiosis affect the inheritance of alleles?
-During meiosis, the maternal and paternal chromosomes separate, ensuring that each gamete receives only one allele for each gene, which is then passed on to offspring.
What is the significance of dominant and recessive alleles in determining physical traits?
-Dominant alleles are expressed physically when at least one is present, while recessive alleles require two copies to be expressed.
How are alleles represented in genetic notation?
-Alleles are represented using upper and lower case letters, with dominant alleles in uppercase and recessive alleles in lowercase.
What terms describe the different genetic combinations of alleles?
-Homozygous dominant refers to two dominant alleles, heterozygous refers to one dominant and one recessive allele, and homozygous recessive refers to two recessive alleles.
What is the difference between phenotype and genotype?
-Phenotype refers to the physical appearance or expressed traits of an individual, while genotype refers to the actual allele combination that determines those traits.
What does the video suggest for further study on genetics?
-The video suggests viewers look at Miss Angler's grade 12 playlist for more in-depth videos on topics like monohybrid and dihybrid crosses and sex-linked disorders.
Outlines
π Introduction to Genetics
This introductory segment to genetics by Miss Angler sets the stage for the video, welcoming viewers to her biology class. She encourages new viewers to subscribe, like, and turn on notifications for regular updates on biology content for grades 8 to 12. Miss Angler also promotes her YouTube membership, which offers exclusive benefits like live lessons and Q&A sessions. The video aims to provide a foundational understanding of genetics, and for those seeking more depth, she directs them to her grade 12 playlist. She begins with a recap of the chromatin network and its condensation into chromosomes during cell division, urging viewers to revisit her meiosis videos for a refresher on chromosome structure. The segment ends with a brief mention of DNA as the carrier of genetic information, coding for all proteins in the body.
𧬠Understanding Genes and Alleles
In this paragraph, Miss Angler delves into the specifics of genetic inheritance, explaining the concepts of genes and alleles. She clarifies that a gene is a segment of DNA that codes for a particular characteristic, such as height or eye color, while alleles are the variations of these genes, like different eye colors. She uses the example of eye color to illustrate how alleles can vary within the same gene. The paragraph also explains the physical representation of alleles on homologous chromosomes, which are pairs of chromosomes that carry alleles for the same gene. Miss Angler emphasizes the importance of distinguishing between genes and alleles, setting the stage for further discussions on inheritance.
πΆ Inheritance of Alleles
This section focuses on the inheritance of genetic traits, detailing how humans inherit one chromosome from each parent, forming homologous pairs. Each chromosome carries alleles for the same gene, and these alleles can vary between the maternal and paternal chromosomes. Miss Angler explains that during meiosis, these homologous chromosomes separate, ensuring that offspring inherit only one allele for each gene from each parent. She uses the example of eye color to demonstrate how different combinations of maternal and paternal alleles can result in different physical traits, or phenotypes, in the offspring. The paragraph also introduces the concept of alleles being represented by letters, with uppercase letters indicating dominant alleles and lowercase indicating recessive ones.
π Dominance and Expression of Alleles
In this segment, Miss Angler discusses the expression of genetic traits, specifically the concepts of dominant and recessive alleles. She explains that dominant alleles are expressed over recessive ones when present in the genotype, using the example of flower color to illustrate this point. The paragraph explores the different possible genotypes and their corresponding phenotypes, such as homozygous dominant, heterozygous, and homozygous recessive. The summary also touches on the importance of understanding these genetic terms for studying and understanding inheritance patterns. Miss Angler wraps up the video with a quick recap of the key terms introduced, including chromatin network, chromosomes, genes, alleles, paternal/maternal chromosomes, dominant and recessive alleles, and homozygous and heterozygous genotypes.
Mindmap
Keywords
π‘Chromatin Network
π‘Chromosomes
π‘DNA
π‘Genes
π‘Alleles
π‘Homologous Chromosomes
π‘Meiosis
π‘Dominant Alleles
π‘Recessive Alleles
π‘Phenotype
π‘Genotype
Highlights
Introduction to genetics with a focus on basic concepts suitable for grade 8 to 12 biology students.
The importance of subscribing and turning on notifications for regular updates on biology content.
Membership benefits on the YouTube channel include exclusive videos and live lessons.
The necessity of understanding the basics of genetics before diving into more complex topics like mono and dihybrid crosses.
Chromatin network's role in the nucleus and its condensation into chromosomes during cell division.
DNA as the 'code of life' that determines all physical traits, from skin to hair.
Genes are sections of DNA that code for specific characteristics, such as height and eye color.
Alleles are variations of genes, like different eye colors, representing physical trait variations.
Homologous chromosomes and their role in carrying alleles for the same gene.
Inheritance of characteristics through the separation of maternal and paternal chromosomes during meiosis.
The concept of alleles being passed on to offspring, with only one allele of each gene being transmitted at a time.
Using upper and lower case letters to denote dominant and recessive alleles, respectively.
Phenotype as the physical expression of an individual's genetic makeup, influenced by dominant and recessive alleles.
Genotype refers to the actual combination of alleles, such as homozygous dominant or heterozygous.
Dominant alleles are expressed physically when only one is present, while recessive alleles require two for expression.
The significance of understanding the difference between homozygous dominant, homozygous recessive, and heterozygous genotypes.
A recap of key genetic terminology to aid in studying and understanding genetic principles.
Transcripts
hi everybody and welcome back to miss
angus biology class i am miss angler and
in today's video we are going to do a
introduction to genetics
now if you are new here don't forget to
give this video a thumbs up like and
subscribe and turn your notifications on
because i post new videos every tuesday
and thursday for grade 8 to 12 biology
also if you are new here don't forget to
sign up for my membership on my youtube
page you can find the join button
on my home page and you can have a look
at the different perks and that are
offered being a member things like
members exclusive videos live lessons
with me question and answer sessions so
go check that out if you're looking for
some extra help as you work your way
through your matricu and into your
finals
now it's important to point out that
this video is an introduction to
genetics if you're needing a little bit
more detail you should go and look at my
grade 12 playlist there you'll find many
videos covering mono hybrid dihybrid
crosses sex link disorders a little bit
more in depth this video here is going
to cover genetics
and the basics around it so let's just
recap a couple of things first things
first we know that in every cell there
is a chromatin network and that
chromatin network is found inside of the
nucleus that we see here now when a cell
is undergoing any form of meiotic or
mitotic division so meiosis or mitosis
that chromatin network is going to
condense into chromosomes now if you're
not so sure what a chromosome is or its
structure you should go look back at my
meiosis videos which i've linked above
now so you can refresh your memory on
all of those basics
now a chromosome is a collection of your
dna and you'll have 46 chromosomes as a
human and chromosomes are condensed
pieces of dna so that means if i zoom in
on just this chunk over here we will
find this piece of dna
that has been condensed now dna is the
code of life we know that it codes for
all the proteins of the body everything
from skin to hair and everything in
between is made via this dna
now the sections of the dna are called
genes in other words if i were to take
all the information from here all the
way down to there that would code for a
specific characteristic
now it's really important to get this
terminology locked down a gene is a type
of a characteristic for example your
height your hair color your eye color
your blood group those are the
characteristics that we find in genes
and those genes express themselves
physically so that we can see them in
people now if you can see them that
would be something like your hair color
right but you can't see someone's blood
group you'd have to have a blood test
for that but we still say that a gene is
the way you express
a characteristic
it's really important now to clarify
this confusion between the word gene and
allele because it's going to make it
really difficult if we don't know the
differences from this point onwards so
first things first as we've established
already a gene is a characteristic so i
want you to think of things like your
height your eye color your blood group
but those particular genes have
variations or types
and we call those things alleles
and an allele is a variation of that
gene for example you have your eye color
gene
and the variation of that gene would be
a blue um
a blue eyed allele a brown eyed allele a
green eyed allele those are all
variations of eye color eye color is the
characteristic and the actual physical
color itself is the allele or the
variation
now let's see these alleles in action as
we already know every human has
homologous chromosomes or homologous
pairs and you remember that from a
previous video you have two chromosomes
that are paired together and they are
paired together because they carry
um alleles
that are for the same gene in other
words they carry
a eye color or they carry your skin
color or something like that where they
must be grouped together because they
carry the same gene
now
we're going to get into more detail
about how you actually inherit those
things but let's just see what they look
like physically what does an allele
actually look like on your chromosomes
so first things first
on these two chromosomes that you have
let's say hypothetically for example
over
here
is where we find your gene for your eye
color
on your one chromosome that you have you
have a blue allele
in that exact location and it must be on
both sides
because both sides of the chromosome are
like mirror images of each other
and then on your other chromosome you
have a different allele let's say you
had green eyes
on this particular
chromosome so that's your allele
now you will notice that the gene is in
exactly the same place
on both of the chromosomes which means
that it is the same characteristic it's
the same gene but the colors are
different and because the colors are
different we say that those are alleles
they are different kinds or different
types
and so what we have here is one gene
but we have two
different
alleles is what we are seeing here two
different alleles
now that we've clarified what an allele
and a gene is we now need to look at how
do you actually pass those
characteristics on
and so in every human being you have 46
chromosomes and they come in pairs or
homologous pairs the pairs are made up
of a maternal chromosome which you got
from your mother and a paternal
chromosome which you got from your
father and what that basically means is
for every single gene in your body you
have two alleles for that gene so as an
example on here
this particular person is going to have
a eye color gene on the one chromosome
from mom
and then on the other we are going to
have maybe a different allele variation
maybe a blue variation for eye color on
the other
so what that means is for every single
one of your genes you will have two
alleles or two versions of that gene and
you are going to pass those on to your
children but separately
and that comes down to having knowledge
in meiosis and so these two chromosomes
are not going to stay together
based off of how meiosis works the
maternal chromosome is going to go off
into its own cell over here
and the paternal chromosome is going to
go off on to another different cell that
will then continue on in the process of
meiosis this separation you may be
familiar with when you think about
anaphase one where we separate the
homologous partners from each other
so now i've gone and i have placed those
chromosomes into separate cells and
they've taken their alleles with them
and so that is why when you have
children you can only pass one
of your alleles on at a time for example
let's say that you were male
um
and it doesn't matter if your male
and your maternal or your paternal is
passed on it's not linked to your sex in
other words if you're male you don't
just pass on paternal traits you can
also pass on maternal ones
um essentially if you were making sperm
cells maybe the sperm cells that were
resultant of this particular cell are
all going to have brown eyed alleles on
them
and then maybe all the sperm cells that
come from this chromosome are going to
have all the blue alleles on them
and so essentially what i'm getting at
here is when you pass on your
characteristics you can only pass on one
of the two alleles that you have at a
time you can never pass on more than
that because if you do you have created
a chromosomal mutation
now to take this even further we need to
describe these alleles
in a way with letters
and what we do is we use upper and lower
case letters to describe the
characteristic
and in this instance because we are
using eye color brown and blue i'm going
to use the letter b for now
and i'm going to elaborate very soon as
to why i'm using capital b's for the 1
and
lowercase b's for the other that has to
do with whether or not the allele is
what we call dominant or is it a
recessive allele and i'm going to
explain that next
now that we understand how we inherit
our alleles from our parents and that we
always have two alleles for every
characteristic we need to now see if
these alleles come in pairs
who gets expressed which one do we
actually use because we don't use both
of them all the time in actual fact
depending on the combination you receive
it will determine what you physically
look like or what characteristic you
have and so that's where we play into a
dominant and a recessive allele
now when we speak about these alleles we
often use letters and for now we're just
going to use the letter b because it's
convenient but you could use any letter
when we talk about dominant alleles
dominant alleles are ones that we use
with a capital letter when we speak
about recessive alleles we use a lower
case letter and that's how we tell the
difference
now
how do you know
what you are going to physically look
like that depends on the combination of
your alleles now as an example below we
have three possible combinations and
they come in twos remember because you
have to have two alleles of every
possible uh gene
one maternal one paternal
you will see that um out of our first
two individuals you could either have
two capital b's
or you could have a capital b and a
lower b and then the third individual is
two lowercase b's and you can see that
their combination actually influences
the way they look
and we call this influence on the way
they look their phenotype which is their
physical appearance it is how they look
and that physical appearance so their
color whether they're purple or white is
influenced by something called their
genotype or their allele
and so their allele pairs are important
so let's have a look at the first allele
pair in this first picture there are two
capital bs which means that this
particular plant has two dominant in
this case purple alleles as the key
describes below so that means 100 this
plant is going to make purple only
flowers no other options
the second version is where you have a
capital b and a lowercase b
now according to the laws that govern
how genetics works which i do cover in a
different video in the monohybrid as
well as in my types of dominance video
which i've linked above now
you will see that when you have this
mixture
you are going to only see the dominant
allele or the capital letter allele
because it dominates it masks the
recessives it's going to come out purple
the third and final option is two
lowercase letters and it's two recessive
alleles that means that those two
alleles are going to make a white
individual and the only time you can
ever have a recessive uh physical
characteristic like in this instance
being white you need to have two in
order to have it
now to summarize that when you are
writing out these characteristics and
specifically you are writing out the
genotype you would say for example that
this organism the first one would be
homozygous dominant homo means the same
dominant means that it has two of the
expressed physical characteristics
if you have a mixture like a big letter
and a small letter we call this
heterozygous hetero meaning two
different
now if you have two smaller case letters
you still use the word homozygous to
describe the genotype however we say
homozygous recessive so that we can tell
that oh this is referring to two small
letters that are the same as opposed to
two big letters for homozygous dominant
now as always at the end of every video
i'd like to do a quick terminology recap
you can use all of these terms in your
flash cards while you study it's the
best way to study terminology first
things first we looked at the chromatin
network which was a recap of a previous
lesson where we looked at that long
twisty noodle-like structure that has
all your dna it's only visible during
interphase and it condenses into
chromosomes chromosomes you have 46 of
them they carry that particular dna we
spoke of earlier in the chromatin
network and they are the ones that
we will be dealing with mostly when we
talk about alleles and being able to see
them and pass them on and crossing over
and stuff like that in meiosis
and then we looked at genes which were
sections of the chromosome that coded
for a specific trait
that one might be your height your eye
color your hair texture and we looked at
variations of those genes which we call
alleles remember that's a variation like
you have the gene for your eye color
that's the gene but then the variation
would be green eyes or blue eyes and so
that is the allele
then we looked at paternal and maternal
chromosomes which remember you inherit
one chromosome from your dad one from
your mom and likewise when you reproduce
your paternal and maternal chromosomes
they must separate from each other so
that only one goes into each of your
gametes we then spoke about dominant
characteristics or alleles which are the
physically expressed alleles when there
is just one present but if you want a
recessive
gene to be expressed you're going to
need at least two
and an example of this maybe in nature
would be if you have brown eyes you only
need one brown allele to have brown eyes
but if you have blue eyes you need at
least two small bees in order or or two
recessive allele should i say
for you to have
blue eyes and lastly we looked at
homozygous and heterozygous which refers
to
the combination of letters that you have
you are either homozygous dominant which
means you've got two capital letters
let's just remind ourselves to capital
letter b's
or you are going to have to lower case
that's what homozygous means dominant or
recessive heterozygous means you have
one capital letter and one lowercase
letter
now that's all for today's video i hope
you enjoyed it um if you like this video
don't forget to give it a thumbs up and
subscribe i post new content every
tuesday and thursday and please turn
your notifications on so you get the
freshest content as soon as i post it
and i will see you all again soon bye
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