EASY TO UNDERSTAND | INTRO TO GENETICS

Summary

In 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

• 📚 The video is an introduction to genetics for grade 8 to 12 biology students.
• 👍 Viewers are encouraged to like, subscribe, and turn on notifications for regular updates.
• 🎓 Miss Angler offers a membership on her YouTube page with exclusive perks like live lessons and Q&A sessions.
• 🧬 Genetics is the study of heredity and variation in living organisms, focusing on DNA and its structure.
• 🧬🧬 Chromosomes are condensed pieces of DNA, with humans having 46 chromosomes in total.
• 🔍 DNA contains genes, which are sections that code for specific traits like height, eye color, and blood group.
• 👀 Alleles are variations of genes, such as different eye colors, and they determine the physical expression of traits.
• 🌟 Dominant alleles are represented by uppercase letters and are expressed physically, while recessive alleles are lowercase.
• 👶 Each person inherits one maternal and one paternal chromosome, resulting in two alleles for each gene.
• 🧬🔄 During meiosis, homologous chromosomes separate, ensuring offspring inherit one allele from each parent.
• 🌼 Phenotype refers to the physical expression of traits, influenced by the combination of dominant and recessive alleles.
• 🔠 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

00:00

🌟 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.

05:00

🧬 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.

10:00

👶 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.

15:01

🔍 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.

Keywords

💡Chromatin Network

The chromatin network is a complex of DNA and proteins found within the cell's nucleus. In the context of the video, it is mentioned as the structure that condenses into chromosomes during cell division. This network is essential for understanding the organization of genetic material and its role in genetics.

💡Chromosomes

Chromosomes are thread-like structures composed of DNA and proteins, and they carry genetic information. In the video, it is explained that humans have 46 chromosomes, which are condensed forms of DNA. Chromosomes are central to the study of genetics as they are the carriers of genes.

💡DNA

DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. It contains the genetic instructions for the development, functioning, growth, and reproduction of all known living organisms. In the video, DNA is described as the 'code of life' that codes for all the body's proteins.

💡Genes

Genes are segments of DNA that contain the instructions for making proteins, which are the building blocks for various bodily functions. The video emphasizes that genes code for specific characteristics such as height, hair color, and eye color, making them a fundamental concept in genetics.

💡Alleles

Alleles are different forms or variations of a gene. They determine the different expressions of a trait, such as different eye colors. In the script, alleles are used to explain the concept of genetic variation and inheritance, with examples like blue, brown, and green eye color alleles.

💡Homologous Chromosomes

Homologous chromosomes are a pair of chromosomes, one from each parent, that have the same genes at the same loci. The video explains that every human has homologous pairs, which carry alleles for the same genes, and these are crucial for understanding how traits are inherited.

💡Meiosis

Meiosis is a type of cell division that reduces the chromosome number by half, creating four gamete cells. It is important in the context of the video because it is the process by which alleles are separated and distributed to offspring, ensuring genetic diversity.

💡Dominant Alleles

Dominant alleles are versions of a gene that express their phenotype even when only one copy is present. In the video, dominant alleles are denoted by uppercase letters and are explained as the alleles that mask the expression of recessive alleles in a heterozygous pair.

💡Recessive Alleles

Recessive alleles are versions of a gene that are only expressed when two copies are present. The video uses lowercase letters to denote recessive alleles and explains that they are only visible when there is no dominant allele present to mask their expression.

💡Phenotype

Phenotype refers to the observable characteristics or traits of an organism, such as hair or eye color. The video describes how the combination of alleles determines an individual's phenotype, with examples of how different allele combinations result in different physical appearances.

💡Genotype

Genotype is the genetic composition of an organism for a specific trait. It is the set of alleles, either dominant or recessive, that an individual has inherited. The video explains how genotypes are denoted using letters and how they relate to the expression of traits.

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

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freshest content as soon as i post it

and i will see you all again soon bye