Fathers Pass Along More Mutations As They Age

ananyo writes "In the 1930s, the pioneering geneticist J. B. S. Haldane noticed a peculiar inheritance pattern in families with long histories of haemophilia. The faulty mutation responsible for the blood-clotting disorder tended to arise on the X chromosomes that fathers passed to their daughters, rather than on those that mothers passed down. Haldane subsequently proposed that children inherit more mutations from their fathers than their mothers, although he acknowledged that 'it is difficult to see how this could be proved or disproved for many years to come.' That year has finally arrived: whole-genome sequencing of dozens of Icelandic families has at last provided the evidence that eluded Haldane. Moreover, the study, published in Nature, finds that the age at which a father sires children determines how many mutations those offspring inherit. By starting families in their thirties, forties and beyond, men could be increasing the chances that their children will develop autism, schizophrenia and other diseases often linked to new mutations (abstract)."

Comments

Hardly surprising

[dkleinsc]

The testes are towards the outside of the body and vulnerable to all sorts of things, while the ovaries are better protected. Furthermore, sperm is produced over the course of a lifetime, whereas eggs aren't. The end result is that eggs are likely to have the original genetic material of Mom, while the sperm is more likely to have been modified (by radiation, damage from trauma, copying errors, etc) from the original genetic material of Dad.

This seems like a good evolutionary strategy, however it arose: Mom provides a version that has allowed her to survive and reproduce, suggesting a minimum viability, which she passes on to the child. Dad provides a version of an evolutionarily successful human that is modified, allowing the species to improve itself (And if he's lived to old age, he was probably an effective survivor evolutionarily speaking).

I have a son with a 'de novo' mutation

[Frans Faase]

I was 35 when I conceived my son. He was diagnosed with a 'de novo' (new) mutation in one of the two copies of his MLL2 gene: a single base pair was deleted at position 2272 ("c.2272delG"). This causes half of his MLL2 proteins to be not working resulting in Kabuki Syndrome. He has an academic IQ of around 50, but with some tasks he out smarts everyone I know: he can instantly see who are missing from a certain setting. Saw him walk into his class room, look around, walk to his teacher and when asked by her who were missing, mention the names without hesitating (or looking around) for a second.