Chromosome one top left, bottom right are the sex chromosomes.

And those individuals who disproportionately suffer from Lups and Rheumatoid Arthritis, and a host of other diseases, are women and they are XX.

I can just draw a bunch of them, and then have the X chromosome that is essentially one of the gender determining chromosomes from my mother.

And then let's say that last one actually helps to determine my gender, or it fully determines my gender.

You have your two chomosomes, each made with sister chromatids, each made with two sister chromatids.

I'll show you an example of that real quickly.

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.

But, as a cancer doc, this is what I see.

It's not like one is getting two versions of a gene and the other is getting two versions of another gene.

It now has four chromosomes.

different species have different numbers of chromosomes.

It's fuckedup chromosomes.

When we talk about meiosis, we have to be careful to show the homologous pairs.

There's a lot of mistakes to be made out there, and the immune system makes them.

So in one instance, you can have somebody who has an XY chromosomal basis, and that SRY gene on the Y chromosome tells the proto gonads, which we all have in the fetal life, to become testes.

So it's analogous to anaphase in mitosis, but the key difference is you're pulling apart homologous pairs.

It didn't have that crossover occur.

So let me say it has this chromosome right here and then

They're being pulled apart, but they're being pulled apart the homologous pair is being pulled apart, not the actual chromosomes, not the chromatids.

And just like in mitosis, as soon as the sister chromatids are split apart, they are now referred to as chromosomes, or sister chromosomes.

These are years that we could get.

He gets split up into two chromatids, which we are now calling chromosomes, or sister chromosomes.

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

She suffers from a chronic illness.

Let's flip the table yet again

18.Rare diseases

Now we're in metaphase, and metaphase really is just an aligning of the chromosomes, so all of the chromosomes are going to be aligned at the center of the cell.

Remember, in interface, even though I drew it this way, they don't exist in this state, the actual chromosomes.

I got from my dad.

Let me do it in blue.

Let me just cut and paste what I have. I have this one, this chromosome right here.

Chimpanzees have two sets of 24, or 24 pairs of chromosomes.

Rhesus monkeys have 21 pairs of chromosomes.

So I have one chromosome from my dad, and it's made up of two chromatids, so it's already replicated, but we only consider it one chromosome, and then I have one from my mom in green.

There's just a gazillion of them that are all duplicates of the cell, and they all contain the 2N number of chromosomes, the diploid number of chromosomes.

So dystonia is a disorder affecting children.

He was taken off the Dutch ship in Martinique and died a week later of consumption. Oh...

But we're going to focus on the region labeled red here and it's the interface between the dynamic scaffolding and the chromosomes.

Sometimes this is called a tetrad because it has four chromatids in it, but it's in a pair of homologous chromosomes.

It's just growing, accumulating materials and building itself out, and then it actually replicates its chromosomes.

Let me see, it'll look like this.

We get one from mom, one from dad.

Once again, we're not even in mitosis yet.

Anaphase I, the homologous pairs were broken up, but the chromosomes themselves were not.

This was at a time that treatment actually existed in rich countries.