Comments on: Just call him/her Ol’ Blue Eyes

By: cloud computing companies

cloud computing companies — Wed, 25 Jan 2012 18:47:55 +0000

cloud computing companies…

[…]neo-neocon » Blog Archive » Just call him/her Ol’ Blue Eyes[…]…

By: Foxfier

Foxfier — Mon, 28 Jun 2010 03:54:29 +0000

You can’t prove something with a system that is based on what you’re trying to prove– that’s circular reasoning. It might be 100% accurate, it’s just not proof.

From the tiny snippet we have (I’m going to assume they did more than a press release for years of study ^.^), they were looking at a single trait, yes, but they only mention that there’s a single identical mutation that causes it. Which is why my first post was about me hoping they had SOMETHING more than just that as a base for the guess.

On a side note, I only just noticed the personification of nature in the quotes by the doctor. Hehe.

By: Sergey

Sergey — Sat, 26 Jun 2010 21:28:39 +0000

No, coalescence is a method, not a theory, and it is based on assumption that any combination of several neutral markers can not be replicated in evolution, it can be only inherited. Usually many such combinations are traced, and they can be inherited in different times from different ancestors. The coalescent is a tree with maximal score, which can explain observed distribution of markers in population with maximal likelihood. It is computed using dynamical programming algorithm.
Traits are not the same as markers. Here only one trait was studied, a mutation of blue eyes, but a lot of markers (neutral mutations in mtDNA) were used in construction of coalescent explaining origin of this trait.

By: Foxfier

Foxfier — Sat, 26 Jun 2010 16:17:49 +0000

Sergey-
if it’s the same mutation, I don’t think it would be possible to narrow it down from just that one gene. You could get evidence that it’s always found with X in this population, and that X is this different from the X in this population in a way that we think indicates separation by Y generations (same way they figure the mitochondrial mother, IIRC)

Huh….from what I can find nosing around, coalescence theory has as a base assumption that all traits are from a single ancestor. If I remember my logic correctly, that means it can’t be used to prove a single ancestor– just to calculate within the assumption.

By: Sergey

Sergey — Sat, 26 Jun 2010 08:34:35 +0000

I have not read the original paper, but if they did coalescence analysis (and they did), they have a positive evidence of a single-mutation origin of the trait. I mean, if in all studied cases the lines of coalescence merge in one point, this assertion is proved. If the trait had a multiple origin, they would get several clasters of lines of descent that does not connect each other in historical time. For example, the Scottish population would have one nearest common ancesstor of all their blue-eyed, Irish population – its own nearest common ancestor, and so on.

By: Wm Lawrence

Wm Lawrence — Sat, 26 Jun 2010 06:35:12 +0000

From what little I remember of my high school biology (way too many years ago) A recessive trait can not be wiped out of a population. It is normally hidden and appears sporadically. I suppose our new found ability to read the genetic code could change that.

By: Foxfier

Foxfier — Fri, 25 Jun 2010 20:40:10 +0000

I hope they have more to back up a single ancestor than all blue-eyes sharing a common mutation… that might be the only way that blue eyes can be found in humans, and (not being obviously bad for survival) it was simply not wiped out.

(I have a not-exactly-personal interest, since my Elf and our darling Kit both have baby-blue eyes.)

By: Curtis

Curtis — Fri, 25 Jun 2010 16:24:53 +0000

Thank you very much for your answer. I was thinking in a different context where the subject was not a person but evolution.

I’ll read the study. Being a monozygotic twin, I know the reality of which you speak. One detail: The one thing both my brother and I retained from our military service was our Commanding Officer’s dictionary. Same red volume with black marker on the top edge memorializing “CO.”

By: Sergey

Sergey — Fri, 25 Jun 2010 16:07:08 +0000

It means a lot of personal traits both physical and mental are predetermined by an unique genetic composition of an individual. Even your choices are largely controlled by your genetic makeup. There was a huge longitudinal study of concordance of personal traits in pairs of monozygotic and dizigotic twins rised up separately in adopting families, known as Minnesota Twin Study. Its results were summed up in popular book “Born this way”. Monozygotic twins showed remarkable coincidence in their habits, career choices, marital choices and even names they gave to their pets. See
http://www.amazon.com/Born-That-Way-Behavior-Personality/dp/0679430288

By: Curtis

Curtis — Fri, 25 Jun 2010 15:36:26 +0000

Sergey: Saying you believe that DNA is destiny is rather disingenuous. Destiny implies “according to plan” and what is DNA except the plan. So what do you mean when you say DNA is destiny?