Comments on: Grandma Plays Favourites: X-Chromosome Relatedness and Sex-specific Childhood Mortality – Proceedings of the Royal Society B

By: onyx

onyx — Tue, 03 Nov 2009 04:17:13 +0000

i also think it will be easy to proof pgm’s function more/better for the survival of grandchildren when they are more sure. i am however quite convinced that mgm’s function more easily in that sense. for an example, woman have cells of all their children in their body’s specifically the brain,
i think it has much a do with the natural direction of their biological empathy’s. (and thus that genes are not all-telling persee , but they are that in combination with merely physical (biological) factors). interestingly that poses the question who was first (the bird or the egg) and when exactly did genetics incorporate these biological effects, pretty well possible before we ever grew into sth. more then a primate, and possibly long before that. allthough the same matter of it’s allways an egg before a bird, interestingly we could perhaps pinpoint a few of the related genetic developments on a timescale. btw. for animals smell usually suffices to make the distinction, and it would be somewhat farfetched to assume humans would have lost all that capacity to turn into humans, altho that be kinda nice and contrary to existing theory.

By: onyx

onyx — Tue, 03 Nov 2009 03:58:28 +0000

wich i technically doubt, simply put we are all offspring of murderous victors, at least in europe. any gene that prominently expresses thus implies that exact result of survivability, i just doubt it did that much to our social structures , i expect more that genes will show to be coherent to neccesary quality’s of that surround. more of a bottom-up thing, then a top-down thing. perhaps it will be debated in eternity.

By: terryt

terryt — Tue, 03 Nov 2009 03:13:36 +0000

“their survival rates granted them a niche automatically, and not so much that the niche granted them survival rates”.

You might have something there. At any rate I think the survival of particular offspring is unlikely to be simply the result of genes on the X chromosome.

By: onyx

onyx — Mon, 02 Nov 2009 19:51:21 +0000

i think you are looking to far, productive members of the group are just tolerated, pretty soon the few woman that thus survived menopause would have a cultural niche. that in the end they doubtlessly contributed to the survival of their offsprings genes, oh well it is true, but i don’t think it is anymore specific then in other great mammals, like eg. whales that are often (seemingly at least) lead by an older female. so what i actually think is their survival rates granted them a niche automatically, and not so much that the niche granted them survival rates.

By: dearieme

dearieme — Fri, 30 Oct 2009 15:58:54 +0000

Actually, light-heartedness apart, that is a mechanism that positively favours the development of ANY unusual characteristics, so long as they are not of themselves an evolutionary disadvantage. By gum. Good Lord, have I contributed to biological science?

By: dearieme

dearieme — Fri, 30 Oct 2009 15:55:44 +0000

Sorry, that’s “putative grandchild”.

By: dearieme

dearieme — Fri, 30 Oct 2009 15:55:16 +0000

A PGM could make a good guess, though, if her child and putative child had some unusual characteristic in common – let us say, for the sake of argument, red hair. Then both grandmas have an incentive to look after the mother and child and then redheadedness could constitute an evolutionary advantage. There you are – the carrot-top explained. Yes, now you ask, I am prepared to accept the Nobel Prize.

By: Luis

Luis — Fri, 30 Oct 2009 11:40:39 +0000

And even today many children are unsure who their father is.

You nailed it here: I did not even consider that the PGM would be affected by that factor but it’s obviously much more important. A MGM knows she has an investment in her daughter children, a PGM knows nothing for sure.

By: terryt

terryt — Fri, 30 Oct 2009 03:45:16 +0000

“I would rather look on sociological factors like greater natural empathy of mothers for her daughter’s well doing (including her offspring)”.

That was my first thought on reading the post and I see no reason to change my mind. And even today many children are unsure who their father is.

By: Luis

Luis — Thu, 29 Oct 2009 20:22:54 +0000

Ok, they argue that the X chr has more genes than it would normally correspond (8%), what twists a bit the maths. But I still don’t think this makes such a huge difference.

And I still don’t get their 31% MGM-GD affinity but just 25% when I correct the figures for that:

100%-8%=94%

PGM-GS: 94/4=23%
MGM-GD: (94/4)+(8/4)=25%
PGM-GD: (94/4)+(8/2)=27%

Unless I’m missing something important, these are the real figures for overall relatedness. There is a difference but it is very small.