What is Relatedness?

Jim McGinn <[email hidden]> wrote or quoted:

Quoted message said:

Tim Tyler <[email hidden]> wrote

Quoted message said:

Quoted message said:

Here's Dawkins on the relationship between man and chimpanzees:

``The 98% doesn't mean we are 98% chimpanzees. And it really matters what unit you choose to
make your comparison."

Implicit in Dawkins' statement here is the supposition that the "unit" can be chosen arbitrarily
to achieve different results in the comparison. This seems, obviously, scientifically untenable to
me. Suppose we were comparing the length of two sticks. And suppose we use inches and determine
that the first stick is twice as long as the second stick. If we were to employ centimeters
instead of inches we would not expect the relative comparative lengths of the sticks to change.

This suggests that the "units" that Dawkins refers to are not really units and/or that the scale
that he is drawing from is greatly lacking in quantitative relevance.

Dawkins is talking about the length of DNA sequence being considered.

If you compare the similarity to two books by counting the letters that are in identical places
between them then you get one value.

If you compare by counting the word similarities to one another, then you get another,
*different* value.

The "letter" relatedness will usually be much greater than the "word" relatedness.

The 98% figure corresponds to "letter" relatedness.

However the "letter relatedness" of two totally unrelated *random* DNA sequences is /still/ in
excess of 12%.

...and consider this example:

"SETS GUN OFF" "LETS RUN OFF"

Here the *letter* similarity is high - but both the word similarity and the meaning
similarity are not.

Sometimes, letter relatedness is not a very good metric - and it should often be considered to be
artificially inflated.
--
__________
|im |yler timtyler.orgtimtyler.orgOpen ↗ [email hidden] Remove lock to reply.

Tim Tyler <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Jim McGinn <[email hidden]> wrote or quoted:

Quoted message said:

Tim Tyler <[email hidden]> wrote

Quoted message said:

Here's Dawkins on the relationship between man and chimpanzees:

``The 98% doesn't mean we are 98% chimpanzees. And it really matters what unit you choose to
make your comparison."

Implicit in Dawkins' statement here is the supposition that the "unit" can be chosen arbitrarily
to achieve different results in the comparison. This seems, obviously, scientifically untenable
to me. Suppose we were comparing the length of two sticks. And suppose we use inches and
determine that the first stick is twice as long as the second stick. If we were to employ
centimeters instead of inches we would not expect the relative comparative lengths of the sticks
to change.

This suggests that the "units" that Dawkins refers to are not really units and/or that the scale
that he is drawing from is greatly lacking in quantitative relevance.

Dawkins is talking about the length of DNA sequence being considered.

The fact that Dawkins and yourself are unable to delineate this "length" proves my point.

Jim

Jim McGinn <[email hidden]> wrote or quoted:

Quoted message said:

Tim Tyler <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Jim McGinn <[email hidden]>

Quoted message said:

Tim Tyler <[email hidden]> wrote:

Quoted message said:

Quoted message said:

Quoted message said:

> Here's Dawkins on the relationship between man and chimpanzees:
>
> ``The 98% doesn't mean we are 98% chimpanzees. And it really matters what unit you choose to
> make your comparison."

Implicit in Dawkins' statement here is the supposition that the "unit" can be chosen
arbitrarily to achieve different results in the comparison. This seems, obviously,
scientifically untenable to me. Suppose we were comparing the length of two sticks. And
suppose we use inches and determine that the first stick is twice as long as the second stick.
If we were to employ centimeters instead of inches we would not expect the relative
comparative lengths of the sticks to change.

[...]

Quoted message said:

Quoted message said:

Dawkins is talking about the length of DNA sequence being considered.

The fact that Dawkins and yourself are unable to delineate this "length" proves my point.

Your point /seemed/ to be that Dawkins was saying:

``that the "unit" can be chosen arbitrarily to achieve different results.''

That's not what the man said - he was pointing out that comparing chunks of text of different length
would give different values for "relatedness" - in much the same way that comparing words and
comparing letters between two books does.

He never said that all the resulting values were equally valid or useful - and thus that the length
could be chosen arbitrarily.

Indeed what he said was just the opposite - he said that: "it really matters what unit you choose" -
since comparing stretches of genome of different lengths can give different results.

He also said that the "letter" relatedness of "98%" did *not* mean that we were "98%" chimpanzees -
saying that this sort of relatedness has drawbacks.
--
__________
|im |yler timtyler.orgtimtyler.orgOpen ↗ [email hidden] Remove lock to reply.

"Jim McGinn" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Tim Tyler <[email hidden]> wrote in message

news:<[email hidden]>...

Quoted message said:

Quoted message said:

Jim McGinn <[email hidden]> wrote or quoted:

Quoted message said:

Tim Tyler <[email hidden]> wrote
> Here's Dawkins on the relationship between man and chimpanzees:
>
> ``The 98% doesn't mean we are 98% chimpanzees. And it really matters what unit you choose to
> make your comparison."

Implicit in Dawkins' statement here is the supposition that the "unit" can be chosen
arbitrarily to achieve different results in the comparison. This seems, obviously,
scientifically untenable to me. Suppose we were comparing the length of two sticks. And
suppose we use inches and determine that the first stick is twice as long as the second stick.
If we were to employ centimeters instead of inches we would not expect the relative
comparative lengths of the sticks to change.

This suggests that the "units" that Dawkins refers to are not really units and/or that the
scale that he is drawing from is greatly lacking in quantitative relevance.

Dawkins is talking about the length of DNA sequence being considered.

The fact that Dawkins and yourself are unable to delineate this "length" proves my point.

As far as my primate (near but not quite chimp-style) brain can overview the relevant science
factual situation, you, Jim, should not expect to find answers to your questions any time soon.

In fact it even appeared [when I percEPTively sniffed the wind - using not my nose but an organ that
produces playfully oracular opinions - in regard to these questions %-] that there will NEVER arise
any such - 'statistically straight-forward' - answers (for us to champion our superiority over
chimpanzees with) other than already available and collectable of data by which we can determine
that we are the champions as far as AEVASIVE adaptability/capacity is concerned.

P

Tim Tyler <[email hidden]> wrote

<snip>

Quoted message said:

Quoted message said:

Quoted message said:

Dawkins is talking about the length of DNA sequence being considered.

The fact that Dawkins and yourself are unable to delineate this "length" proves my point.

Your point /seemed/ to be that Dawkins was saying:

``that the "unit" can be chosen arbitrarily to achieve different results.''

That's not what the man said - he was pointing out that comparing chunks of text of different
length would give different values for "relatedness"

Did he not use the word, "units?"

Quoted message said:

- in much the same way that comparing words
and comparing letters between two books does.

He never said that all the resulting values were equally valid or useful - and thus that the
length could be chosen arbitrarily.

It seems he was saying that the "unit" could be chosen arbitrarily to achieve whatever end
one wished.

Quoted message said:

Indeed what he said was just the opposite - he said that: "it really matters what unit you choose"
- since comparing stretches of genome of different lengths can give different results.

And you think this is a good thing?

Quoted message said:

He also said that the "letter" relatedness of "98%" did *not* mean that we were "98%" chimpanzees
- saying that this sort of relatedness has drawbacks.

What's needed is a more rational and consistent understanding of relatedness. After this is achieved
we can then try to narrow it down to biological relatedness.

Jim