Older fathers pass on more genetic mutations, study shows - Polidicks

[quote][I]According to scientists, rates of conditions such as autism and schizophrenia could be a result of the rising age of fatherhood[/I] The rising age of fatherhood could be a factor in increased rates of conditions such as schizophrenia and autism, scientists say, after new research suggesting that older fathers pass on more genetic mutations to their children. A child will normally have 60 new mutations in its genetic sequence (out of a total of more than 3bn DNA letters) passed on from its parents. Despite being a tiny fraction of the sequence, these differences are the root of much of the diversity in the human genomes and, over long periods of time, amount to a significant force in human evolution. "Most of these mutations are probably neutral," said Kari Stefansson, chief executive of deCODE Genetics in Iceland, who led the latest work, published on Wednesday in Nature. "Occasionally, they will be deleterious, they will lead to a disease. Once in a blue moon, you will get a mutation that confers a selective advantage. We showed that some of these mutations are in genes that have been indicated in diseases like autism and schizophrenia." A single-letter mutation in a gene called APP can confer protection against Alzheimer's disease and help people live longer, for example, while a single-letter mutation in the CTFR gene causes cystic fibrosis. Similar single-letter mutations in genes are behind sickle cell anaemia and even colour blindness. Stefansson said a 40-year-old father was approximately twice as likely to conceive a child that developed autism as a 20-year-old father, although the overall risk remained low. The increase in risk factor for schizophrenia went up by a similar amount. "It's incredibly important to recognise that, even though there is a doubling in risk of a 40-year-old father conceiving a child that develops schizophrenia compared to a 20-year-old, the overall risk is still not above 1%," he said. Stefansson urged fathers not to worry about having children at an older age. "This has been a fact of life for centuries – nothing has changed with this. This is only giving us an opportunity to quantify the changes that are happening in genomes," he said. He hoped that the work would, however, shift some of the focus from the increasing age of the mother to the increasing age of the father when it came to concerns about developmental disorders in children. Alexey Kondrashov of the department of ecology and evolutionary biology at the University of Michigan, in an accompanying analysis for Nature, said: "In humans, as many as 10% of point mutations are deleterious, so [Stefansson's] findings suggest that an average newborn carries six new deleterious mutations. Although most of these mutations will, on their own, have only mild effects, collectively they could have a substantial impact on health." Stefansson's team studied the mutation rates in 78 Icelandic parent-offspring trios and found that a 20-year-old father transmits, on average, around 25 mutations to his child, whereas a 40-year-old father transmits around 65. Every additional year of the father's age meant an average of two extra mutations in the child. In comparison, the number of new mutations passed on by the mother was always around 15, regardless of her age. In Iceland, where the study was carried out, the age of fathers at conception had risen from an average of 27.9 years in 1980 to 33 years in 2011, mainly owing to increased education and the higher use of contraception. In the UK, the average age of fathers in 2008 was 32.4, up from 31.5 a decade earlier. Autism spectrum disorders are known to have some genetic triggers and increased rate of mutations from older fathers might be a factor. In Iceland, where the study was carried out, the age of fathers at conception had risen from an average of 27.9 years in 1980 to 33 years in 2011, mainly due to increased education and the higher use of contraception. In the UK, the average age of fathers in 2008 was 32.4, up from 31.5 a decade earlier.Stefansson said that a 40-year-old father was approximately two times more likely to conceive a child that developed autism than a 20-year-old father, although the overall risk remained low. The increase in risk factor for schizophrenia went up by a similar amount. "It's incredibly important to recognise that, even though there is a doubling in risk of a 40-year-old father conceiving a child that develops schizophrenia compared to a 20-year-old, the overall risk is still not above 1%," he said. Despite the research, Stefansson urged fathers not to worry about having children at an older age. "This has been a fact of life for centuries - nothing has changed with this [research], this is only giving us an opportunity to quantify the changes that are happening in genomes," he said. He hoped that the work would, however, shift some of the focus from the increasing age of the mother to the increasing age of the father, when it came to concerns about developmental disorders in children. Kondrashov said it was unsurprising that disorders of brain function, such as autism, schizophrenia, dyslexia and reduced intelligence, seemed particularly affected by the age of the father. "This is consistent with the fact that more genes are expressed in the brain than in any other organ, meaning that he fraction of new mutations that will affect its functions is the highest." He added that the reason that older fathers passed on more mutations was easily explained by the fact that "in mammals, male germ cells (sperm) are continually produced, so they go through many more cell divisions over the course of a generation than do female germ cells (eggs), which are not actively dividing in individuals of reproductive age". Darren Griffin, professor of genetics at the University of Kent, said that, though the effect observed by Stefansson was significant, it should not necessarily cause great worry among prospective older fathers. "This study only considered single DNA letter changes. However, overall DNA damage in the sperm as well as more gross genomic [chromosomal] age-related changes on the egg should be considered. The maternal age effect on chromosomal abnormalities is a far more potent and measurable." Allan Pacey, an andrologist at the University of Sheffield and chairman of the British Fertility Society, said it was a surprise to find that men transmitted a higher number of mutations to their children than women. "While not wanting to scare the children of older fathers, information like this is important to understand and should remind us that nature designed us to have our children at a young age and if at all possible men and women should not delay parenthood if they are in a position not to." Older fathers pass on more genetic mutations to their children than mothers and younger fathers, according to a study of familial genome sequences. Scientists said that the rising age of fathers could, therefore, be a factor in the increased rates of conditions such as schizophrenia and autism seen in many western societies. A child will normally have 60 new mutations in her genetic sequence (out of a total more than 3bn DNA letters), passed on from her parents. Despite being a tiny fraction of the sequence, these differences are the root of much of the diversity in the human genomes and, over long periods of time, amount to a significant force in human evolution. "Most of these mutations are probably neutral," said Kari Stefansson, chief executive of of deCODE Genetics in Iceland, who led the latest work,[/quote] [url=http://www.guardian.co.uk/science/2012/aug/22/older-fathers-genetic-mutations-research?CMP=twt_fd]Source[/url] It's bad for women to have kids later on as well, so heh.

I thought we already knew this? I learned this in school a long time ago.

you guys must have really old parents.

My mom is 61 :v: she was 43 when I was born, probably why I had to be put in a incubator just to survive.

[QUOTE=SpaceGhost;37360468]My mom is 61 :v: she was 43 when I was born, probably why I had to be put in a incubator just to survive.[/QUOTE] Your mum was your father?

[QUOTE=Bumrang;37360121]I thought we already knew this? I learned this in school a long time ago.[/QUOTE] I learned this in High School Biology.

[QUOTE=BrainDeath;37362284]Your mum was your father?[/QUOTE] What?

Explains why I have the feet of a Sasquatch, that and I've walked barefoot on tile floors for years.

I was conceived when my dad was 20 and my mum 21. Having young parents is awesome.

Things have turned upside down. Usually high mutation rates are good for the specie because that allows much faster adaption to a specific environment. But now, thanks to modern medical science, even individuals with harmful mutations can spread their genes to future generations instead of dying before reaching maturity. I wonder if humans are evolving at all anymore. Though you should not be worried, according to the National center for biotech information each human zygote averages around 128 mutations, and almost all of them are fully harmless.

And older parents make children more longevous.

My dad is 60 now Oh god what if I have super powers but I don't know it

I thought this was because the older you got the more your DNA mutated and degraded over time, hence why we age?

My parents were both in their late 40s when I was born. Guess that means I'm special.

I'm almost certain the mother's age is the more important factor.

[QUOTE=Strider*;37369085]I'm almost certain the mother's age is the more important factor.[/QUOTE] Why? Both the mother and father provide the child's genetic material in the form of Sperm/Egg, so both parent's DNA could be responsible for genetic mutations.

[QUOTE=Strider*;37369085]I'm almost certain the mother's age is the more important factor.[/QUOTE] Well. The mothers is more down to mental issues or wether the kid lives at all. Father... well, that's worse.

That explains why I'm here on facepunch instead of out with friends.

Guess that explains why I acted like such a retard when I was younger.

My mum was 31 and my father 35 when I was born.

Genetic mutations haven't got much to do with being retarded, stop making excuses guys

[QUOTE=LtKyle2;37374626]Guess that explains why I acted like such a retard when I was younger.[/QUOTE] [QUOTE=jiggu;37370365]That explains why I'm here on facepunch instead of out with friends.[/QUOTE] Um no it doesn't, these types of character feautures don't really heavily depend on genes.

[QUOTE=Maucer;37363168]Things have turned upside down. Usually high mutation rates are good for the specie because that allows much faster adaption to a specific environment. But now, thanks to modern medical science, even individuals with harmful mutations can spread their genes to future generations instead of dying before reaching maturity. [B]I wonder if humans are evolving at all anymore. [/B] Though you should not be worried, according to the National center for biotech information each human zygote averages around 128 mutations, and almost all of them are fully harmless.[/QUOTE]Interesting you'd say that. [media]http://www.youtube.com/watch?v=UkuCtIko798[/media]