Can current science deduce who originated who?

[CharonY 2059]

17 minutes ago, Ali NasserEddine said:

Were we able to identify this relation (subspecies) only because they were domesticated?

No, even without knowledge we would know that they are a kind of wolves (i.e. same species). The distinction into subspecies is somewhat arbitrary. I do not know specifically on the genetic level how divergent they are, but the morphological differences would be quite obvious. But again, subspecies distinctions are a wobbly concept at best.

 

17 minutes ago, Ali NasserEddine said:

Doesn't this contradict the concept that wolves are the ancestors of dogs? Unless you mean that there was a living object x, which became a wolf at one point, and the wolf became a dog at a later stage.

No, dogs are a subspecies, i.e. they are wolves. They are just a specific sub-group of wolves. They are not a different species. It would make more sense you if you look at e.g. jackals, foxes, coyotes and other canidae. If you look at relationship on this level you will see that dog and gray wolves group together as one species, the next relatives are coyotes, then the golden Jackal, then the Ethiopian wolf and so on.  Maybe this can help you in looking at these things.

 

17 minutes ago, Ali NasserEddine said:

This is very important to my understanding. Was the molecular clock used for identifying the relation between wolves and dogs?

No, molecular clocks are only good in measuring large divergence. For short-time changes they are usually rather unreliable. And again, wolves and dogs are too close to each other to make real distinctions on that level. 

Edit: I should add, that it is not impossible, it just requires very careful calibration of mutation rates. What one need is basically genetic information from ancestors of current wolves and dogs (which would be found ca. 20-30k years ago) . While that has not been traditionally possible, nowadays one could obtain such information from somewhat well-preserved specimen (especially dry and cold areas).

 

Edited February 15, 2018 by CharonY

[Ali NasserEddine 1]

4 minutes ago, CharonY said:

Maybe this can help you in looking at these things.

Thanks a lot Charon, well noted. I looked at the link; very illustrative dendrograms.

However, I am confused. I understand that dogs and wolves are the same species, but how could we tell that wolves are the ancestors? This concept has been long in existence, even before the advancement in modern science and scientific tools.

Have scientists derived this conclusion based on physical similarities? I was hoping that the case that @StringJunky presented is true because this would be a shortcut for what I am looking for. I quote it here:

On 2/14/2018 at 6:24 PM, StringJunky said:

To OP: If we take a population of dogs and analyse their DNA and then do the same with wolves, I think you would find DNA evidence of wolves in all dogs but not the other way around; not all wolves carried the mutation which led to dogs, so we can surmise, with a high degree of confidence, that dogs came after wolves.

If the concept of subspecies is based on similarities, well, it might be but it also might not be. For example, as per the suggestion of @DrP, I watched this video on the laryngeal nerve. At 0.37, he says: "obviously a ridiculous detour, no engineer would ever make a mistake like that". Here is another viewpoint on the matter "RLN Is Not Evidence of Poor Design".

Just so I don't get lost, could you please share your opinion on the question I asked before in response to @StringJunky reply that I quoted above?

3 hours ago, Ali NasserEddine said:

To understand it correctly, if we consider a sample of 10 wolves and 10 dogs, we would find DNA evidence of wolves in all the 10 dogs, but not vice versa. However, as per @Moontanman comment, it is possible to find evidence of dogs in some wolves (3 out of 10 for example). If my understanding is correct, could you please advise if there is any scientific reference for this?

[StringJunky 2100]

15 minutes ago, Ali NasserEddine said:

Just so I don't get lost, could you please share your opinion on the question I asked before in response to @StringJunky reply that I quoted above?

As I said to Moon earlier, I was making an educated guess and would always defer to CharonY. He is much more well-versed in this subject than I am. If Arete chimes in. this is his field. CharonY may be coming across as a bit vague to you and not giving a resolute presentation but that is the  state of current knowledge.

Edited February 15, 2018 by StringJunky

[Ali NasserEddine 1]

2 minutes ago, StringJunky said:

As I said to Moon earlier, I was making an educated guess and would always defer to CharonY. He is much more well-versed in this subject than I am.

Well noted. Many thanks.

[CharonY 2059]

20 minutes ago, Ali NasserEddine said:

However, I am confused. I understand that dogs and wolves are the same species, but how could we tell that wolves are the ancestors? This concept has been long in existence, even before the advancement in modern science and scientific tools.

I am not sure about the natural history of how folks first determined it. But rather obviously it was known that dogs are a domesticated species and that it would have to originated from some wild forms and the most likely candidate (geographically and morpohologically) were wolves or perhaps coyotes. As genetic analyses have shown that grey wolves and dogs are most closely related, the conclusion seems rather obvious. 

However, if we want to be very precise, it is actually quite a bit more complicated. It is not clear, for example if the ancestor of the dog is actually the gey wolf we see today, or perhaps a common ancestor of the modern grey wolf. Also, there is potential admixture afterward. I am not sure how well that has been resolved, though.

[Bender 204]

Not only can DNA analysis track species through time, it can also show migration patterns. Link

 

 

1 hour ago, Ali NasserEddine said:

For example, as per the suggestion of @DrP, I watched this video on the laryngeal nerve. At 0.37, he says: "obviously a ridiculous detour, no engineer would ever make a mistake like that". Here is another viewpoint on the matter "RLN Is Not Evidence of Poor Design".

Please don't put too much weight into such apologetic nonsense.

[Ali NasserEddine 1]

3 hours ago, CharonY said:

I am not sure about the natural history of how folks first determined it. But rather obviously it was known that dogs are a domesticated species and that it would have to originated from some wild forms and the most likely candidate (geographically and morpohologically) were wolves or perhaps coyotes. As genetic analyses have shown that grey wolves and dogs are most closely related, the conclusion seems rather obvious. 

However, if we want to be very precise, it is actually quite a bit more complicated. It is not clear, for example if the ancestor of the dog is actually the gey wolf we see today, or perhaps a common ancestor of the modern grey wolf. Also, there is potential admixture afterward. I am not sure how well that has been resolved, though.

Thanks a lot Charon for the clarification; well noted and very much appreciated.

3 hours ago, Bender said:

Not only can DNA analysis track species through time, it can also show migration patterns. Link

Thanks a lot Bender for the link. However, if they could trace a story that dates back to 33,000 years ago, wouldn't it be easily possible to identify the ancestry relation between wolves and dogs that are currently available. I refer to the last post by @CharonY:

4 hours ago, CharonY said:

were wolves or perhaps coyotes

So, it is uncertain. Please note that Charon was nominated by many here as one of the most familiar with this science field in this forum.

I really wish not to lose the point that brought me here. If you could help me understand the following, I would be indeed grateful:

8 hours ago, Ali NasserEddine said:

To understand it correctly, if we consider a sample of 10 wolves and 10 dogs, we would find DNA evidence of wolves in all the 10 dogs, but not vice versa. However, as per @Moontanman comment, it is possible to find evidence of dogs in some wolves (3 out of 10 for example). If my understanding is correct, could you please advise if there is any scientific reference for this?

 

[Moontanman 2183]

5 hours ago, Ali NasserEddine said:

Hi Charon, many thanks for this information; well noted. Further to your reply, could you please help me understand some of your statements?

Were we able to identify this relation (subspecies) only because they were domesticated?

Actually no, there are natural subspecies, usually this indicates that the gene pools are separated but the separation didn't occur long ago enough for their genes to be incompatible.  This can be true for species as well, neanderthals are considered a different species of human but we do carry evidence that we did mix our genes in the distant past. 

5 hours ago, Ali NasserEddine said:

Doesn't this contradict the concept that wolves are the ancestors of dogs? Unless you mean that there was a living object x, which became a wolf at one point, and the wolf became a dog at a later stage.

No, think of your first cousin, you both share a common ancestor who might still be alive but neither of you are that ancestor nor ancestral to each other. Object X can be your ancestor and still be alive. It reminds me of the old question if humans descended from monkeys why are there still monkeys. The answer is that while humans and extant monkeys share a common ancestor and that ancestor, if alive today would be classified as a monkey, we are not descended from any monkeys alive today... 

5 hours ago, Ali NasserEddine said:

This is very important to my understanding. Was the molecular clock used for identifying the relation between wolves and dogs?

I'm sure this was one method used to estimate the time since wolves and dogs last shared a common ancestor the molecular clock is not required to show common ancestry... 

[Ali NasserEddine 1]

Hi Moontanman, thanks a lot. All are well noted.

7 minutes ago, Moontanman said:

No, think of your first cousin, you both share a common ancestor who might still be alive but neither of you are that ancestor nor ancestral to each other. Object X can be your ancestor and still be alive. It reminds me of the old question if humans descended from monkeys why are there still monkeys. The answer is that while humans and extant monkeys share a common ancestor and that ancestor, if alive today would be classified as a monkey, we are not descended from any monkeys alive today... 

This is understood, but what I am exactly after is to know whether there is a methodology that allows us to identify the hierarchical relation between two living objects. I used the example of wolves and dogs because it is common, but it could be anything else, like two types of birds. Actually, the educated guess of @StringJunky is exactly to the point. If his idea is correct, then, my requirement would be satisfied.

However, after all the help I got through this forum, and for which I am sincerely grateful, I think that proving such relations is not straight forward. My initial thought was that it can be done through DNA tests, but it seems I was wrong.

[Moontanman 2183]

17 minutes ago, Ali NasserEddine said:

Hi Moontanman, thanks a lot. All are well noted.

This is understood, but what I am exactly after is to know whether there is a methodology that allows us to identify the hierarchical relation between two living objects. I used the example of wolves and dogs because it is common, but it could be anything else, like two types of birds. Actually, the educated guess of @StringJunky is exactly to the point. If his idea is correct, then, my requirement would be satisfied.

However, after all the help I got through this forum, and for which I am sincerely grateful, I think that proving such relations is not straight forward. My initial thought was that it can be done through DNA tests, but it seems I was wrong.

I am pretty sure I can be done with genetic testing, possibly someone else is better informed... 

[Bender 204]

It is possible to track mutations through populations. The number of mutations unique to one group compared to another gives an indication for the amount of generations the groups were separated.

As has been repeatedly pointed out, both groups will have mutations, and there is little point trying to nominate one as the ancestor of the other.

One group can appear more similar to the ancestor for various reasons, but that doesn't mean a thing.

In short: there is no test to identify hierarchical relations, because there is no hierarchy between coexisting  (sub)species.

[Ali NasserEddine 1]

On 2/16/2018 at 8:03 PM, Bender said:

In short: there is no test to identify hierarchical relations, because there is no hierarchy between coexisting  (sub)species.

Thanks a lot Bender. This answers my enquiry.

[CharonY 2059]

On 2/16/2018 at 1:03 PM, Bender said:

It is possible to track mutations through populations. The number of mutations unique to one group compared to another gives an indication for the amount of generations the groups were separated.

As has been repeatedly pointed out, both groups will have mutations, and there is little point trying to nominate one as the ancestor of the other.

One group can appear more similar to the ancestor for various reasons, but that doesn't mean a thing.

In short: there is no test to identify hierarchical relations, because there is no hierarchy between coexisting  (sub)species.

Actually there are potential scenarios in which hierarchies could exist, though I am not sure whether examples exist. One case would be the isolation of a small subpopulation which would undergo rapid speciation (say, due to strong selection). At the same time, the original population maintains a stable gene pool (e.g. because of size, free gene flow etc.). After divergence, the original population could still be indistinguishable from the ancestor population, whereas the isolated one would become new species or sub-species (depending on divergence in the given time frame).

 

[Bender 204]

I agree, but I think DNA testing would be able to distinguish the original and new populations. There would be some genetic drift and new mutations  (possibly in the junk DNA).

I guess a criterion for hierarchy could be that one population would produce fertile offspring with the ancestor, while the other wouldn't. I admit pretty worthless, as it is impossible to test.

As you say, there could only be hierarchy in very specific cases.

[Ali NasserEddine 1]

22 hours ago, CharonY said:

Actually there are potential scenarios in which hierarchies could exist, though I am not sure whether examples exist. One case would be the isolation of a small subpopulation which would undergo rapid speciation (say, due to strong selection). At the same time, the original population maintains a stable gene pool (e.g. because of size, free gene flow etc.). After divergence, the original population could still be indistinguishable from the ancestor population, whereas the isolated one would become new species or sub-species (depending on divergence in the given time frame).

 

Dear Charon, your comment is highly appreciated. For someone who is completely out of the domain like me, any information can cause distortion. So, thanks alot.

On the other hand, could you please advise on the door of this science for someone new to the field? Do you think that the starting point would be a bachelor in specific biology field? Or is there a shortcut? (for example, particular set of courses). The hope is to contribute to this field, and arrive at a method. From my experience in scientific research (holder of PhD), there would be a huge space for relatively easy improvements in any field.

[CharonY 2059]

Well, obvious areas would be evolution and population genetics. There are text books around with which one could start. 

[delboy 36]

'Evolution' by Futuyma and Kirkpatrick seems like a standard text book to me.