|
Register | Sign In |
|
QuickSearch
Thread ▼ Details |
Thread Info
|
|
|
Author | Topic: How do you define the word Evolution? | |||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10038 Joined: Member Rating: 5.3 |
caffeine writes: The reason Taq is so inordinately fond of these mice as an example of evolution, though, is that there is not one allele for dark colouration. I would put that 3rd on the list of reasons I like this example. The 1st reason is that they were able to correlate the phenotypic change to mutations in a specific gene. The 2nd reason is that we know that this mutation could not have existed in ancestral pocket mice because the basalt outcroppings appeared in just the last few million years. Prior to these volcanic eruptions there were only brown mice because the black allele would have been selected against and removed from the population.
|
|||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10038 Joined: Member Rating: 5.3 |
Faith writes: In any case it is still true that to get one color means losing the other colors. Getting a new color does not require the loss of the other color, as you have tried to claim.
|
|||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10038 Joined: Member Rating: 5.3
|
Faith writes: In the population that must be black for the sake of survival it does mean either losing or severely reducing other colors.
But you don't need to eliminate the other color in order to have black mice, which is what you claimed before. It is the mutations that produce black fur, not the removal of the brown allele.
|
|||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10038 Joined: Member Rating: 5.3
|
Faith writes: But for the black fur to characterize the whole population in the black environment . . . That is not what we are talking about. You said that natural selection produces the black fur. This is false. It is mutations that produced the black fur, not selection.
|
|||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10038 Joined: Member Rating: 5.3
|
CRR writes: Coat colour is controlled in large part by the interaction of two proteins, the melanocortin-1-receptor (MC1R) and the agouti-signaling protein. The mutations in mcr1 prevent this interaction resulting in dark coats. So it's not that the mice have gained the ability to produce dark coats but rather they have lost control of the colour resulting in dark coats. So it is a loss of function mutation; one that is beneficial when the mice live on dark rocks. Dark coat colors are a gain in function: "In the laboratory mouse, loss-of-function mutations at Mc1r are recessive and result in light color, whereas gain-of-function alleles are dominant and result in dark color (16)."Just a moment...
|
|||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10038 Joined: Member Rating: 5.3
|
Faith writes: I mean and always mean that A WHOLE POPULATION of a particular phenotype is produced by selection, not the black fur itself. Would you also agree that black fur color was produced by a mutation, and that mutation is beneficial?
I've said over and over that it doesn't matter how the genetic diversity is produced, whether by mutation or built in alleles, when you have evolution, meaning the production of a population of new phenotypes, it can only happen by the reduction of genetic diversity. At one point there was just brown mice. Due to a mutation, there is now black and brown mice. This is evolution. How is this a reduction in genetic diversity when you go from one phenotype to two phenotypes?
|
|||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10038 Joined: Member Rating: 5.3
|
Faith writes: I don't know what to think of the mutation theory. It may be a mutation, but it doesn't matter. It does matter. The paper lists the mutations in the Mcr1 gene that are associated with black fur. Do you have any reason to doubt that these mutations are the cause for black fur in these mice? Why are you so reluctant to accept these mutations as the source of black fur?
Again, it's the selection that reduces the genetic diversity, and it's the selection that creates the new population, or in some cases "species." In the new population there is only the one phenotype. There are two phenotypes in this population where there used to be one. You keep ignoring this fact.
|
|||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10038 Joined: Member Rating: 5.3 |
Faith writes: No no no no no. Loss of genetic diversity is necessary to evolution, to the formation of new phenotypes, new species etc. These mice did not have lose their brown fur in order to evolve black fur. Before the mutations there was just brown fur. After the mutations, there are now mice with black and brown fur. How is this not an increase in genetic diversity?
you still have to reduce or get rid of the genetic material that is not part of the new phenotype/species. Reduction of one allele is now considered a loss in genetic diversity? Really? Before mutations: 100% brown alleleAfter mutations: 10% black fur, 90% brown fur You are saying that after the mutations there is less genetic diversity?
|
|||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10038 Joined: Member Rating: 5.3
|
Faith writes: My definition of the Kind is functional, defined by the point at which evolution runs out of genetic diversity. Evolution never runs out of genetic diversity because new alleles are created by mutations all of the time.
|
|||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10038 Joined: Member Rating: 5.3
|
Faith writes: You don't need mutation for adaptations either, just new combinations of existing alleles. What combinations of existing human alleles will produce an elephant?
|
|||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10038 Joined: Member Rating: 5.3
|
RAZD writes:
That was more of a guesstimate. The actual number is probably a bit lower since the black basalt outcroppings make up a small percentage of their overall range. And ... black is dominant ... so, the Hardy-Weinberg equation gives us: Edited by Taq, : No reason given.
|
|||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10038 Joined: Member Rating: 5.3
|
CRR writes: I was talking about loss of function between the MC1R gene and the agouti-signaling protein.They are talking gain/loss of function as it relates to coat colour.. Dominant/recessive does not determine gain/loss of functional information. A normal light switch can be turned on or off. A broken light switch can result in a light permanently on (dominant) or permanently off (recessive); but the switch is broken in either case. Similarly with the MC1R gene. You are claiming that any change, no matter what it is, is a broken switch. That is just denial.
|
|||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10038 Joined: Member Rating: 5.3
|
RAZD writes: So 90% of statistics used in arguments are made up on the spot? +/- 1.8%. Don't forget the standard deviation.
|
|
|
Do Nothing Button
Copyright 2001-2023 by EvC Forum, All Rights Reserved
Version 4.2
Innovative software from Qwixotic © 2024