Are women born with all the eggs they'll ever produce?

[lumberjim]

That's what they told me in 10th grade biology. Seems like it can't be right. If they were..... How would we have evolved at all?

So, you're born with all your eggs, and they gradually deplete as you age and at some point you exhaust the supply, have hot flashes, act like a bitch, and then calm down. But?

If that was the case..... If you were born... eggs intact, all spoken for.... From the jump.... That would mean the egg half of the zygote you started as,... is exactly the same as the half your mother was born with, right? Because she was also born with all of her eggs. And her mom. Where would mutation or evolution get hold of the xx side, ever?

Does all mutation come from changes to the male DNA, that occurs prior to the production of the sperm that brings the Y chromosome?

Studies say mice can produce new eggs if they have loss of significant amounts of born eggs. Stem cells will regenerate if need be. Difficult to discern in humans. Still.... Smart bodies we have.

Women can create, nurture, and deliver new humans. That's awesome. But is it only Men that can create better humans? Does all mutation and evolution originate in the male hemisphere?

[Clodfobble]

The female fetus's eggs form as she forms, just like all her other organs. They are each formed from her DNA, which is a mix of her mom's and dad's.

Remember Punnet Squares? Dad has brown eyes, no recessive blue, so he's BB, mom is blue-eyed, she's bb. (Eye color is actually more complex, but shut it.) So all of mom's eggs have b, and all of dad's sperm have B. Mom gets pregnant, a b egg with a B sperm. So her girl fetus's DNA is Bb, in every cell from the beginning. Now girl fetus develops ovaries, then eggs, which split one extra time like all gametes. Girl baby is born with brown eyes and full of eggs, half of which are B and half of which are b. Outwardly she has brown eyes like dad, but half her eggs contain recessive blue eyes from her mom, and HER fetus might one day be formed from a b egg, and have blue eyes and nothing but b eggs if she marries a blue-eyed dude.

[lumberjim]

Yes. But. You're describing combinations and statistial variation. If the X coming from mom was there from her creation, then no change that occurs to her during her life will alter the actual egg, so to whatever extent her genes carry to the fetus, they were there from the start. Unchanged. Unless the eggs can change. Maybe they can, I don't know. Not so concerned with varying combinations of x and y. But externally influenced changes.

Like if, as a 20 year old, I do an inordinate amount of lsd, and it changes the way my mind works, can that transmit through my sperm and my kids would have some residual effect? But their mom already had her eggs done, so if she did just as much acid, would it even matter?
The x that comes from the fathers mother could be changed, but only while the father carried it.

[Undertoad]

no change that occurs to her during her life will alter the actual egg

This is how it is.

[xoxoxoBruce]

The Xs and the Ys are each a label for a bag with tons of data sequences. That's where genes are storing information, and gene splicing comes in.

Maybe cocaine Katy can embroideries on your genes.

[Undertoad]

Like if, as a 20 year old, I do an inordinate amount of lsd, and it changes the way my mind works, can that transmit through my sperm and my kids would have some residual effect?

No

This is what I believe.

[xoxoxoBruce]

I believe you're correct, however chemicals might change more than the way your mind works. The kid might be a shower rather than grower.

[sexobon]

We don't know. Most studies are related to drug use and fertility, not genetic alterations passing on to offspring. Few people use only one drug for meaningful drug studies along those lines let alone separating the affects of multiple drugs (e.g. alcohol and cocaine) from the affects other physical deviations.

While some associations have been made, like men's methamphetamine use and heart abnormalities in offspring, cause and affect has not been established for most drugs. We can't say they cause problems; but, we can't rule it out either. That there aren't enough studies to rule it out by even just a preponderance of the evidence has been one of the obstacles in getting drugs like marijuana legalized.

[Undertoad]

(After some reading)

It won't change the DNA sequence. What might change are the how the genes express themselves through epigenetics; this is how the same sequence produces different results. It seems to take a pretty harsh condition to cause that. The studies on it are all about famine and war.

Wikipedia on Transgenerational epigenetic inheritance

[xoxoxoBruce]

But Monsanto, Dow, DuPont, et al, are working on a solution. Dozens of solutions in fact, any one of which might be a game(gene) changer.

[lumberjim]

With how little we actually know about things... Any glimmer of uncertainty looms large.

Check back here 25 years from now.

[Diaphone Jim]

I learned I biology about mammals in general:
"The ova, which are the female sex cells, are much larger than the sperm and are normally formed within the ovaries of the fetus before its birth."
So I am comfortable with "yes."
I am also somewhat tired from producing gazillions of sperm cells for most of my life.

[xoxoxoBruce]

But it's a pleasure to dispose of them.

[Peterdowe]

"But it's a pleasure to dispose of them. "

Yup, real pleasure.

[xoxoxoBruce]

I spotted this today, I guess that proves some things get handed down. Makes me want to see the generations in between to see if it skipped.