So I had that one chromosome there, and then I have another one here.

So I have a chromosome.

So this is a single chromosome.

This is one chromosome right here.

She's got two x's.

Humans usually have 46 chromosomes, two sets of 23, or simply 23 pairs of chromosomes.

The other is the X chromosome.

She has one regular X chromosome and then she has one X chromosome that has the I'll put a little superscript there for hemophilia she has the hemophilia mutation.

In a human's case, you would have 46 of them.

If you've got a y chromosome, you are a male.

Now men, they only have one X chromosome.

And you have two strands of DNA in each chromosome.

So this is one chromosome there and this is the other chromosome here.

The book of you would have 46 chapters, one for each chromosome.

So let me zoom in on chromosome number 3.

Remember, chromosome is just a big if you take the DNA, the

And the long one right here, it's been the convention to call that the x chromosome.

Since females only have X's to pass on in their egg cells, and males can give either an X or a Y in their sperm cells, the sex is determined by the father and the chance of producing a male or a female is 50 50.

Even though we have two chromatids, one for each chromosome, now we have four chromatids, two for each chromosome, we still say we only have two chromosomes.

Identifying genes on each chromosome is an active area of genetic research.

Identifying genes on each chromosome is an active area of genetic research.

But for a son, he can only get the X chromosome from his mother.

However, the other genes of the X chromosome cause feminization as well.

1q21.1 deletion syndrome or 1q21.1 (recurrent) microdeletion is a rare aberration of chromosome 1.

Chromosome 2 is the second largest human chromosome, spanning more than 242 million base pairs (the building material of DNA) and representing almost 8 of the total DNA in cells.

Chromosome 2 is one of the 23 pairs of chromosomes in humans.

We have the ability now to build a large robot that can make a million chromosomes a day.

And in the other case, the sperm is carrying an X chromosome, meeting the X chromosome of the egg.

This was an African man who gave rise to all the Y chromosome diversity around the world.

Well, every chromosome has to have either of those, so these are going to add up to 100 , or equal to 1.

46 chromosomes combine with 30,000 different genes to determine your gender, body type, color of hair, eyes, skin, and even certain characteristics of your personality.

We find all kinds of species that have taken up a second chromosome or a third one from somewhere, adding thousands of new traits in a second to that species.

Females with trisomy X have three X chromosomes, for a total of 47 chromosomes per cell.

In meiosis, the chromosome pairs splits and a representative of each pair goes to one daughter cell.

The Y chromosome, the piece of DNA that makes men men, traces a purely paternal line of descent.

And if we isolate just one chromosome, we're going to pull it out and have a look at its structure.

He's pulled over one copy of each oh, I used a different color one copy of each chromosome to himself.

And in this scenario, I want to imagine that, in one case, the sperm is carrying a Y chromosome, meeting that X chromosome of the egg.

Because a daughter can get one X from the father, one X from the mother, it's kind of diluted out.

Now, I have two chromosomes, one from my father and one from my mother, so let's say that this is the chromosome from my mother.

So maybe for this chromosome I get it from my dad, from the next chromosome, I get it from my mom.

But what's even more amazing is that if you look at the Y chromosome side, the male side of the story, the Y chromosome Adam only lived around 60,000 years ago.

We have 23 pairs of chromosomes, and in each pair, we have one chromosome from our mother and one chromosome from our father.

Or it could go the other way.

So for a man to exhibit hemophilia, to have this phenotype, he just needs it only on the one X chromosome he has.