Comments on: Why sons inherit their mother’s curse

By: Kevin Sweeney

Kevin Sweeney — Tue, 17 May 2011 01:15:27 +0000

I’ve got your male mutational load right here.
(sorry… =P )

By: Christina

Christina — Sat, 14 May 2011 00:21:08 +0000

@Catherine
Actually, the male mitochondrion does enter the ovum, but is subsequently tagged with ubiquitin and destroyed. “[T]he mitochondria, and therefore the mitochondrial DNA, usually comes from the egg only. The sperm’s mitochondria enter the egg but do not contribute genetic information to the embryo. Instead, paternal mitochondria are marked with ubiquitin to select them for later destruction inside the embryo.” from Wikipedia. It cites a ScienceNews article, but that article is subscription-only. I’ve read this in other books on genetics as well.

By: Catherine steacy

Catherine steacy — Fri, 13 May 2011 16:22:46 +0000

@Claire and Christina,
the male mitochondria are not inherited because they do not enter the egg.
The head of the sperm contains the nucleus. This is the only paart of the sperm to enter the egg.The mid piece which has the mitochondria and the tail remain outside the egg.
So only female mitochondria are inherited.

By: Catherine steacy

Catherine steacy — Fri, 13 May 2011 16:20:30 +0000

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By: Christina

Christina — Fri, 13 May 2011 14:24:04 +0000

@Claire – I would presume that a major reason the maternal mitochondria usually win is that the ova are massively larger than the sperm, and thus start out with large numbers of mitochondria, whereas the sperm has only one or two mitochondria. Thus, maternal mitochondria start out massively outnumbering paternal mitochondria.

By: Strombio Lentatric

Strombio Lentatric — Fri, 13 May 2011 09:13:21 +0000

This is a well written article.

By: marvin

marvin — Fri, 13 May 2011 05:13:26 +0000

Very interesting.
I’m an XXY.

By: Winston Yee

Winston Yee — Fri, 13 May 2011 03:46:04 +0000

Hi Ed, that was beautifully told, and this is coming from a member of Dowling’s lab group. I especially like your computer and USB analogy.

By: Claire Ainsworth

Claire Ainsworth — Thu, 12 May 2011 21:36:24 +0000

Great post! Given the selection pressure to escape the “mother’s curse”, is there any evidence that paternal mitochondria evolve ways to bypass the mechanisms that exclude them from the fertilised egg? I have come across reports of paternally-inherited mitochondria in the literature (see, for e.g. http://www.nejm.org/doi/full/10.1056/NEJMoa020350 and http://www.nature.com/nature/journal/v352/n6332/abs/352255a0.html ). Admittedly, these cases are rare, but it got me wondering if there was some kind of arms race going on between egg and sperm, and why the egg appears to be winning…