Sperm, egg and aging

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So, if the male is age 30 and the female is age 28 with the sperm and egg, why isn't their baby starts at age 29? That means the DNA damage theory shouldn't happen, each male and female would give half of their chromosomes (23) created through meiosis and fuse them to form a zygote beginning at age zero. If DNA damage theory does happen, somewhere along the line there would have been a perfect repair of DNA. So what do you think is the difference in age between the zygote and the male and female?
 

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  • #2
Choppy
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So, if the male is age 30 and the female is age 28 with the sperm and egg, why isn't their baby starts at age 29? That means the DNA damage theory shouldn't happen, each male and female would give half of their chromosomes (23) created through meiosis and fuse them to form a zygote beginning at age zero. If DNA damage theory does happen, somewhere along the line there would have been a perfect repair of DNA. So what do you think is the difference in age between the zygote and the male and female?
From a genetic point of view, who says that it doesn't? From a certain point of view you could consider specific genes (or perhaps the genes' codes) to be millions or even billions of years old.

I think one important thing to remember is that the phenomenon of age as we experience it, is more than just an accumulation of genetic damage. And I don't think there's any requirement for the DNA to be "perfect" - whatever that means. It needs to be functional, but that's about it.
 
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  • #3
Evo
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So, if the male is age 30 and the female is age 28 with the sperm and egg, why isn't their baby starts at age 29? That means the DNA damage theory shouldn't happen, each male and female would give half of their chromosomes (23) created through meiosis and fuse them to form a zygote beginning at age zero. If DNA damage theory does happen, somewhere along the line there would have been a perfect repair of DNA. So what do you think is the difference in age between the zygote and the male and female?
It would really help if you would post links to what you've read that has lead to your misunderstandings so that we can clarify for you.

This is an article about how the age of the mother can impact the viability of the egg. There is a lot of information how children of older mothers are more prone to birth defects. you just need to do some simple searches.

The multidisciplinary research team set out to learn whether maternal age is important in the accumulation of mitochondrial DNA (mtDNA) mutations, both in the mother and in the child as a result of transmission. Collaborating with Ian Paul, a pediatrician at the Penn State Milton S. Hershey Medical Center, they took samples of blood and of cells inside the cheek from 39 healthy mother-child pairs. Because mtDNA is inherited only maternally, paternal mtDNA was not a factor in the study. Studying healthy individuals gave the researchers a baseline for future studies of disease-causing mutations.

Through DNA sequencing, they found more mutations in blood and cheek cells in the older mothers in the study. Maternal age of study participants ranged from 25 to 59. "This finding is not surprising," Makova said, "because as we age, cells keep dividing, and therefore we will have more mutant genes." But finding greater rates of mutations in children born to the older mothers did come as a surprise. The researchers believe a similar mutation process is occurring both in the cells of the mothers' bodies and in their germ lines.
http://science.psu.edu/news-and-events/2014-news/Makova10-2014
 
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  • #4
jim mcnamara
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Whew. I'm not posting citations - there are too many required. Simply and without lots of technical terms:
1. Human females begin meiosis as a fetus. It is "held" midway until ovulation. A woman 28 years old has "eggs" that have been on hold for 28 years, (take away about 4 months).
2. Human males continuously undergo meiosis. So complete "sperm creation" takes less than 45 days or so.

Meiotic failures increase as a function of the woman's age versus when the "egg" started meiosis. Therefore defects which relate to 'goofed-up' meiosis, like Down's Syndrome, increase as a percentage of live births as Mom gets older. Not necessarily as Dad gets older. Dad can have problems, too. They are just not as blatantly obvious. And not always directly age-related, like the meiotic problems Mom has.
 
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  • #5
Evo
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I think Jim has a good point, we would have to teach a course on reproduction to answer the OP's wrong and too broad questions. Thread closed. Op needs to do some searches, which would be very easy.
 
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