Selfish Genes

Understanding pedigrees, inbreeding, dosage, etc.

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Patuxet
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Selfish Genes

Postby Patuxet » Fri Jul 22, 2011 3:47 pm

Pedigree journalist Jay Leimbach posted this provocative observation to another forum.

In the July 2nd edition of Science News magazine there is an intriguing article called "Evolution's Wedges: Finding the genes that drive one species into two".

Near the end is the following quote:


"Theorists began to wonder whether individual genes could be as selfish as individual organisms. Since animals usually carry two copies of most chromosomes, the average maternal or paternal version gets passed down to only half of a creature's progeny.

Selfish genes, on the other hand, are downright Machiavellian, maneuvering themselves into as many offspring as possible. These sort of cheaters place themselves far more than 50% in the next generation and, therefore, get a huge evolutionary advantage..."

Apparently there is solid evidence for this phenomenon happening, and obviously it has major implications for horse breeding and pedigrees containing the likes of Nasrullah, Northern Dancer, Mumtaz Mahal, and La Troienne, et al...where a single presence of such a selfish ancestor could create unusual dominance for several generations...
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Postby Tappiano » Fri Jul 22, 2011 6:47 pm

Sounds like some people's egos.....

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Pan Zareta
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Re: Selfish Genes

Postby Pan Zareta » Sat Jul 23, 2011 1:49 pm

Patuxet wrote:Pedigree journalist Jay Leimbach posted this provocative observation to another forum.

In the July 2nd edition of Science News magazine there is an intriguing article called "Evolution's Wedges: Finding the genes that drive one species into two".

Near the end is the following quote:


"...theorists began to wonder whether individual genes could be as selfish as individual organisms. Since animals usually carry two copies of most chromosomes, the average maternal or paternal version of each gene gets passed down to only half of a creature's progeny. Selfish genes, on the other hand, are downright Machiavellian, maneuvering themselves into as many offspring as possible. These sort of cheaters place themselves far more than 50% in the next generation and, therefore, get a huge evolutionary advantage..."

Apparently there is solid evidence for this phenomenon happening, and obviously it has major implications for horse breeding and pedigrees containing the likes of Nasrullah, Northern Dancer, Mumtaz Mahal, and La Troienne, et al...where a single presence of such a selfish ancestor could create unusual dominance for several generations...


Patuxet,
I've taken the liberty of clarifying 'who said what' based upon the Evolution's Wedges article at ScienceNews, and a msg. Jay posted to tbpedix. Jay's remarks are in blue italics. The paragraph in black italic was Jay quoting from the ScienceNews article. Underlined are three words accidentally dropped from that quote. Without them it reads as though parent organisms were passing unrecombined chromosomes on to the next generation, which was not the case. What has been documented are genes that are preferred during recombination, or at some other point during gamete formation. That has intriguing implications for many species.

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Postby brogers » Fri Jul 29, 2011 4:55 pm

Further to the point made above, Jay made a hell of an assumption that Northern Dancer, et al had/have these so called 'selfish genes', if they exist at all in the thoroughbred. The sort of statement that Jay has made, and I am sure it was not his intention, ends up being treated as fact, just because it was said.
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Postby jellac » Tue Aug 02, 2011 8:03 pm

brogers - I didn't take the same opinion of what Jay wrote re: Northern Dancer, et als with regard to the so-called "selfish genes" as you did.

I took Jay's statement to mean that if (an assumption on his part that is not contra the article) that all creatures have at least some selfish genes then those individuals that are heavily (some would say over) represented in subsequent generations due to their preferential use in breeding next generations, their prepotentcy as sires of sires and breeders regular use of inbreeding and linebreeding to those individuals - we can assume have passed on more of their selfish genes because inbreeding of individuals from a pool that is skewed statisticly to offer more crosses that go back to same orginal genetic makeup will have more of those individuals' genetic material, and likely made more so when / if that genetic material includes/included selfish genes.

Not saying that you're wrong or that Jay is correct but simply that I think there is more than one way to interpret what Jay is inferring with his statement.

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ElPrado
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Postby ElPrado » Tue Aug 02, 2011 11:36 pm

Maybe this is an instance of genes replicating normally,
and then doubling in the replication process.
Multiple occurences of certain gene sequences in different spots,
or perhaps consecutively.

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Postby Bill from WA » Wed Aug 03, 2011 6:03 pm

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