Can current science deduce who originated who?

[Ali NasserEddine]

Dear all,

I am a researcher in Finance; pretty far from biology. Could you please help me answer the following question?

- Can current science deduce the origin of a mammal? For example, it is well circulated that dogs originate from wolves? Can I, with absolute certainty, prove this with the current available science tools?

Thanks a lot.

Ali

[DrP]

There are evolutionary charts which depict the relationships and ancestry of all the animals.... we all descend from fish.  I think these have been backed up with more scientific data from DNA analysis of animals and fossil remains since the 1990's.  So - a DNA test will show your relationship between wolves and dogs.

I hope this helps - there are those that are far more knowledgeable than I here in this field that can help you further should you require it.

[koti]

18 minutes ago, Ali NasserEddine said:

Dear all,

I am a researcher in Finance; pretty far from biology. Could you please help me answer the following question?

- Can current science deduce the origin of a mammal? For example, it is well circulated that dogs originate from wolves? Can I, with absolute certainty, prove this with the current available science tools?

Thanks a lot.

Ali

Evolution works more like a tree with various branches growing from each other, some dry out and fall off, some connect and form other branches, its a large and complex system. It doesn’t work in a simple manner like pop science tells us. You might find this helpful:

https://en.m.wikipedia.org/wiki/Evolution_of_mammals

[Ali NasserEddine]

2 minutes ago, DrP said:

There are evolutionary charts which depict the relationships and ancestry of all the animals.... we all descend from fish.  I think these have been backed up with more scientific data from DNA analysis of animals and fossil remains since the 1990's.  So - a DNA test will show your relationship between wolves and dogs.

I hope this helps - there are those that are far more knowledgeable than I here in this field that can help you further should you require it.

Thanks a lot DrP; much appreciated. I understand that science can relate two mammals, but I need to know if it can allow us to deduce, with great certainty, who originated who.

For example, in a DNA paternity testing, "only the characteristics inherited by the child from the father are determined" (source at the end). This makes me feel that if  two samples are collected (child & father), unless I know which one belongs to the father, I can't identify it. Thus, the test only determines if there is a relation, but not who originated who.

Again, thanks a lot. I appreciate your help, and will be waiting for others' input as per your post.

Source:

https://www.bj-diagnostik.de/paternity-test/paternity-test-father-child

 

1 minute ago, koti said:

Evolution works more like a tree with various branches growing from each other, some dry out and fall off, some connect and form other branches, its a large and complex system. It doesn’t work in a simple manner like pop science tells us. You might find this helpful:

https://en.m.wikipedia.org/wiki/Evolution_of_mammals

Thanks a lot Koti for your reply. Regarding the link, this is exactly why I am asking here. Unfortunately, I haven't been exposed to biology since at least 18 years ago. I hoped that by posting here, someone would direct me to the exact concept (tool) which can be used for such identification, if any; so I can study it. Kindly note that if this concept doesn't exist, I am considering to enroll for bachelor in biology in the near future.

Thanks again.

[koti]

27 minutes ago, Ali NasserEddine said:

Thanks a lot DrP; much appreciated. I understand that science can relate two mammals, but I need to know if it can allow us to deduce, with great certainty, who originated who.

For example, in a DNA paternity testing, "only the characteristics inherited by the child from the father are determined" (source at the end). This makes me feel that if  two samples are collected (child & father), unless I know which one belongs to the father, I can't identify it. Thus, the test only determines if there is a relation, but not who originated who.

Again, thanks a lot. I appreciate your help, and will be waiting for others' input as per your post.

Source:

https://www.bj-diagnostik.de/paternity-test/paternity-test-father-child

 

Thanks a lot Koti for your reply. Regarding the link, this is exactly why I am asking here. Unfortunately, I haven't been exposed to biology since at least 18 years ago. I hoped that by posting here, someone would direct me to the exact concept (tool) which can be used for such identification, if any; so I can study it. Kindly note that if this concept doesn't exist, I am considering to enroll for bachelor in biology in the near future.

Thanks again.

I am far from being an expert on evolution and biology but there are very knowledgeable people in this area here who will be able to guide you. @CharonY @Arete

[Ali NasserEddine]

1 minute ago, koti said:

I am far from being an expert on evolution and biology but there are very knowledgeable people in this area here who will be able to guide you. @CharonY @Arete

Thanks a lot Koti. I do really appreciate your kind help.

[DrP]

58 minutes ago, Ali NasserEddine said:

Thanks a lot DrP; much appreciated. I understand that science can relate two mammals, but I need to know if it can allow us to deduce, with great certainty, who originated who.

For example, in a DNA paternity testing, "only the characteristics inherited by the child from the father are determined" (source at the end). This makes me feel that if  two samples are collected (child & father), unless I know which one belongs to the father, I can't identify it. Thus, the test only determines if there is a relation, but not who originated who.

There are clues in anatomy that show that we are all related to fish (look up the Laryngeal nerve in Fish and Giraffes - there is a good youtube vid of a giraffe dissection). These days though the DNA shows that we are related...  it is pretty obvious which one came from who. ;-) IDK how DNA analysis shows this hereditary, but I think it can be used to deduce who are related and which came from what. You need to wait for an expert or look it up on the net if you want deeper details.   

[Area54]

@Ali NasserEddine I belive that your question is fundamentally "How does cladistics operate?" My biology is largely self taught and so has large gaps and probably lots of misunderstandings, but I think a look at cladistics would help you. Cladistics is an effective approach at biological classification that explicitly deals with the sort of relationships you are asking about. Try these links and come back with any questions that arise from them.

https://en.wikipedia.org/wiki/Cladistics

http://palaeos.com/systematics/cladistics/cladogram.html

https://rationalwiki.org/wiki/Cladistics

[Moontanman]

2 hours ago, Ali NasserEddine said:

Thanks a lot DrP; much appreciated. I understand that science can relate two mammals, but I need to know if it can allow us to deduce, with great certainty, who originated who.

For example, in a DNA paternity testing, "only the characteristics inherited by the child from the father are determined" (source at the end). This makes me feel that if  two samples are collected (child & father), unless I know which one belongs to the father, I can't identify it. Thus, the test only determines if there is a relation, but not who originated who.

Again, thanks a lot. I appreciate your help, and will be waiting for others' input as per your post.

Source:

https://www.bj-diagnostik.de/paternity-test/paternity-test-father-child

 

Thanks a lot Koti for your reply. Regarding the link, this is exactly why I am asking here. Unfortunately, I haven't been exposed to biology since at least 18 years ago. I hoped that by posting here, someone would direct me to the exact concept (tool) which can be used for such identification, if any; so I can study it. Kindly note that if this concept doesn't exist, I am considering to enroll for bachelor in biology in the near future.

Thanks again.

Are you asking if there is a modern animal that is ancestral to mammals? 

[Ali NasserEddine]

4 hours ago, DrP said:

There are clues in anatomy that show that we are all related to fish (look up the Laryngeal nerve in Fish and Giraffes - there is a good youtube vid of a giraffe dissection). These days though the DNA shows that we are related...  it is pretty obvious which one came from who. ;-) IDK how DNA analysis shows this hereditary, but I think it can be used to deduce who are related and which came from what. You need to wait for an expert or look it up on the net if you want deeper details.   

Thanks a lot. I just watched the video (Richard Dawkins demonstrates laryngeal nerve of the giraffe).

Stunning. Really stunning, and extremely good to know. Thanks again; much appreciated.

 

2 hours ago, Moontanman said:

Are you asking if there is a modern animal that is ancestral to mammals? 

No. What I am after is to know whether current scientific tools can, with absolute certainty, tell that x came from y (ex: dogs came from wolves). If yes, I am keen to fully know and learn this technique.

[Moontanman]

6 minutes ago, Ali NasserEddine said:

Thanks a lot. I just watched the video (Richard Dawkins demonstrates laryngeal nerve of the giraffe).

Stunning. Really stunning, and extremely good to know. Thanks again; much appreciated.

 

No. What I am after is to know whether current scientific tools can, with absolute certainty, tell that x came from y (ex: dogs came from wolves). If yes, I am keen to fully know and learn this technique.

No, science doesn't deal in absolutes... Science constructs models that conform to the data. The ancestors of mammals can be traced back in the fossil record to the Cambrian but since they do not have DNA from the time period they have to use body shape and structure. Dimetrodon is one of the more famous reptiles that is considered to similar to the mammal reptile link, synapsids really, reptiles is no longer considered to be a separate group.   

[Ali NasserEddine]

4 hours ago, Area54 said:

@Ali NasserEddine I belive that your question is fundamentally "How does cladistics operate?" My biology is largely self taught and so has large gaps and probably lots of misunderstandings, but I think a look at cladistics would help you. Cladistics is an effective approach at biological classification that explicitly deals with the sort of relationships you are asking about. Try these links and come back with any questions that arise from them.

https://en.wikipedia.org/wiki/Cladistics

http://palaeos.com/systematics/cladistics/cladogram.html

https://rationalwiki.org/wiki/Cladistics

Thanks a lot Area54; very helpful.

Actually, this is about what I am looking for. However, it doesn't answer my question. For example, in the first link, we can read "therefore, members of a group are assumed to share a common history and are considered to be closely related."

What I want to know is not whether science can determine whether two living objects are closely related, but if x, with 100% certainty, is the source of y.

Could you please advise if I am getting something wrong?

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Hi @Moontanman

For some reason, I can't reply to posts anymore; so, I put my reply here.

Thanks a lot for the information. If we consider dogs and wolves, I always hear that the latter is the origin of the former. Do you think science can confirm that dogs were wolves since they both still exist? Please note that I am not asking whether science can show that they are related or very related.

Edited February 14, 2018 by Ali NasserEddine
I can't reply to a reply.

[StringJunky]

5 minutes ago, Ali NasserEddine said:

Thanks a lot Area54; very helpful.

Actually, this is about what I am looking for. However, it doesn't answer my question. For example, in the first link, we can read "therefore, members of a group are assumed to share a common history and are considered to be closely related."

What I want to know is not whether science can determine whether two living objects are closely related, but if x, with 100% certainty, is the source of y.

Could you please advise if I am getting something wrong?

Science doesn't do proof, it can only say something is likely with some degree of probability, which can be expressed mathematically.

[Moontanman]

14 minutes ago, Ali NasserEddine said:

Thanks a lot Area54; very helpful.

Actually, this is about what I am looking for. However, it doesn't answer my question. For example, in the first link, we can read "therefore, members of a group are assumed to share a common history and are considered to be closely related."

What I want to know is not whether science can determine whether two living objects are closely related, but if x, with 100% certainty, is the source of y.

Could you please advise if I am getting something wrong?

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Hi @Moontanman

For some reason, I can't reply to posts anymore; so, I put my reply here.

Thanks a lot for the information. If we consider dogs and wolves, I always hear that the latter is the origin of the former. Do you think science can confirm that dogs were wolves since they both still exist? Please note that I am not asking whether science can show that they are related or very related.

Yes this can be demonstrated quite accurately... 

[koti]

1 hour ago, Ali NasserEddine said:

Thanks a lot Area54; very helpful.

Actually, this is about what I am looking for. However, it doesn't answer my question. For example, in the first link, we can read "therefore, members of a group are assumed to share a common history and are considered to be closely related."

What I want to know is not whether science can determine whether two living objects are closely related, but if x, with 100% certainty, is the source of y.

Could you please advise if I am getting something wrong?

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Hi @Moontanman

For some reason, I can't reply to posts anymore; so, I put my reply here.

Thanks a lot for the information. If we consider dogs and wolves, I always hear that the latter is the origin of the former. Do you think science can confirm that dogs were wolves since they both still exist? Please note that I am not asking whether science can show that they are related or very related.

Theres an anti spam thing which gives new members only 5 posts to post untill some time passes. As to your question of whether x comes from y with 100% certainty the answer is yes and no depending on the system. If we are trying to detemine childs mother, we can know with 100% certainty when we witness the birth. DNA tests never give 100% certainty.

Edited February 14, 2018 by koti

[Area54]

19 minutes ago, Ali NasserEddine said:

What I want to know is not whether science can determine whether two living objects are closely related, but if x, with 100% certainty, is the source of y.

Science tends not to deal with 100% certainties. I see Moontanman has already mentioned that.

I understand your phrase "x is the source of y" to be the same as "x is the ancestor of y". (That would be the more usual way of putting it and so if you see that phrase you know it is referencing the topic you are interested in.)

We can establish these sorts of relationships with a good probability of success, but no single technique is used to establish these relationships. Rather comparison of genotype (the DNA of living specimens, or geologically recent specimens), anatomy, embryology, geographic distribution, behvioural traits, etc. are all in the mix. Keep in mind also that we are building on and steadily improving two or more centuries worth of obsevation, collection and analysis.

I appreciate that this is not the clear cut answer you are looking for, but the net result of these approaches is that we can say - with 100% certainty - that amphibians evolved from fish, that reptiles evolved from amphibians, that mammals evolved from the synapsid reptiles and so on. As we get more detailed we are more likely to be in the position of saying that x was the ancestor of y, or closely related to the ancestor of y.

I hope that clarifies rather than confuses.

As koti said we have no doubt at all that dogs evolved from wolves, for here we have the luxury of being able to examine the DNA of both. In a similar way we know that some humans, primarily Europeans have a few % of Neandertal DNA, indicating cross breeding between the two species in Europe. This conclusion is possible because some Neandertal fossils contain enoough residual DNA for analysis.

Edited February 14, 2018 by Area54

[StringJunky]

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.

Edited February 14, 2018 by StringJunky

[Moontanman]

9 minutes ago, 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.

From what I understand there is some gene drift from domestic dogs back to wolves as well. Black coloration evolved in dogs and was passed back to wolves at some relatively recent point.. 

[StringJunky]

20 minutes ago, Moontanman said:

From what I understand there is some gene drift from domestic dogs back to wolves as well. Black coloration evolved in dogs and was passed back to wolves at some relatively recent point.. 

Right, but not all wolf populations would show it, would they?  I'm not saying this with any degree of confidence but it seems to make sense to me. 

[Moontanman]

43 minutes ago, StringJunky said:

Right, but not all wolf populations would show it, would they?  I'm not saying this with any degree of confidence but it seems to make sense to me. 

Actually, if i remember correctly, it was a documentary and we all how "accurate" they can be it was asserted that is only occurs in some populations, the implication was it was a North American Population but it has been a while and I don't remember. OT, I really shouldn't have posted it, just confuses the issue... 

[Area54]

There is a 2004 study in Italy into the origin of black wolves. Occurrence of black wolves in the Northern Apennines, Italy . (https://link.springer.com/article/10.1007/BF03192528) Unfortunately the article itself is behind a paywall, but here is the abstract:

The occurrence of black-coated individuals in wolfCanis lupus Linnaeus, 1758 populations is not surprising itself, but their presence in populations recovering from a severe numerical decline has been considered a possible sign of crossbreeding with the domestic dog. In the northern Apennines (Italy), black wolves occur at a non-negligible frequency. In a 3300 km² area, 22% of wolves observed and 23% of all dead wolves found were represented by animals with a completely black coat. One ‘black’ wolf belonging to the studied population was analysed by a set of microsatellite loci, and no trace of hybridization was found in its ancestry. This result induced us to consider the occurrence of a black phenotype in this area possibly derived from a natural combination of wolf alleles in coat colour determining genes, and not necessarily as the result of crossbreeding with the domestic form.

And this may be the study that Moontanman was aware of through the documentary. "Molecular and Evolutionary History of Melanism in North American Gray Wolves" And the good news is that the complete article is freely available. In the meantime here is the abstract.

Morphological diversity within closely related species is an essential aspect of evolution and adaptation. Mutations in the Melanocortin 1 receptor (Mc1r) gene contribute to pigmentary diversity in natural populations of fish, birds, and many mammals. However, melanism in the gray wolf, Canis lupus, is caused by a different melanocortin pathway component, the K locus, that encodes a beta-defensin protein that acts as an alternative ligand for Mc1r. We show that the melanistic K locus mutation in North American wolves derives from past hybridization with domestic dogs, has risen to high frequency in forested habitats, and exhibits a molecular signature of positive selection. The same mutation also causes melanism in the coyote, Canis latrans, and in Italian gray wolves, and hence our results demonstrate how traits selected in domesticated species can influence the morphological diversity of their wild relatives.

Note that the conclusion here  (black wolves arose from interbreeding with dogs) contrasts with the conclusion in Italy (the black colouration arose independently).

Edited February 14, 2018 by Area54

[Moontanman]

11 minutes ago, Area54 said:

There is a 2004 study in Italy into the origin of black wolves. Occurrence of black wolves in the Northern Apennines, Italy . (https://link.springer.com/article/10.1007/BF03192528) Unfortunately the article itself is behind a paywall, but here is the abstract:

The occurrence of black-coated individuals in wolfCanis lupus Linnaeus, 1758 populations is not surprising itself, but their presence in populations recovering from a severe numerical decline has been considered a possible sign of crossbreeding with the domestic dog. In the northern Apennines (Italy), black wolves occur at a non-negligible frequency. In a 3300 km² area, 22% of wolves observed and 23% of all dead wolves found were represented by animals with a completely black coat. One ‘black’ wolf belonging to the studied population was analysed by a set of microsatellite loci, and no trace of hybridization was found in its ancestry. This result induced us to consider the occurrence of a black phenotype in this area possibly derived from a natural combination of wolf alleles in coat colour determining genes, and not necessarily as the result of crossbreeding with the domestic form.

And this may be the study that Moontanman was aware of through the documentary. "Molecular and Evolutionary History of Melanism in North American Gray Wolves" And the good news is that the complete article is freely available. In the meantime here is the abstract.

Morphological diversity within closely related species is an essential aspect of evolution and adaptation. Mutations in the Melanocortin 1 receptor (Mc1r) gene contribute to pigmentary diversity in natural populations of fish, birds, and many mammals. However, melanism in the gray wolf, Canis lupus, is caused by a different melanocortin pathway component, the K locus, that encodes a beta-defensin protein that acts as an alternative ligand for Mc1r. We show that the melanistic K locus mutation in North American wolves derives from past hybridization with domestic dogs, has risen to high frequency in forested habitats, and exhibits a molecular signature of positive selection. The same mutation also causes melanism in the coyote, Canis latrans, and in Italian gray wolves, and hence our results demonstrate how traits selected in domesticated species can influence the morphological diversity of their wild relatives.

Note that the conclusion here  (black wolves arose from interbreeding with dogs) contrasts with the conclusion in Italy (the black colouration arose independently).

Thanks, I was too lazy to look it up, but I was sure I "remembered it" very interesting the two studies disagreed. 

[Ali NasserEddine]

21 hours ago, koti said:

Theres an anti spam thing which gives new members only 5 posts to post untill some time passes. As to your question of whether x comes from y with 100% certainty the answer is yes and no depending on the system. If we are trying to detemine childs mother, we can know with 100% certainty when we witness the birth. DNA tests never give 100% certainty.

Many thanks Koti. Now, I am able to post again.

Well noted regarding the certainty.

21 hours ago, Area54 said:

Science tends not to deal with 100% certainties. I see Moontanman has already mentioned that.

I understand your phrase "x is the source of y" to be the same as "x is the ancestor of y". (That would be the more usual way of putting it and so if you see that phrase you know it is referencing the topic you are interested in.)

We can establish these sorts of relationships with a good probability of success, but no single technique is used to establish these relationships. Rather comparison of genotype (the DNA of living specimens, or geologically recent specimens), anatomy, embryology, geographic distribution, behvioural traits, etc. are all in the mix. Keep in mind also that we are building on and steadily improving two or more centuries worth of obsevation, collection and analysis.

I appreciate that this is not the clear cut answer you are looking for, but the net result of these approaches is that we can say - with 100% certainty - that amphibians evolved from fish, that reptiles evolved from amphibians, that mammals evolved from the synapsid reptiles and so on. As we get more detailed we are more likely to be in the position of saying that x was the ancestor of y, or closely related to the ancestor of y.

I hope that clarifies rather than confuses.

As koti said we have no doubt at all that dogs evolved from wolves, for here we have the luxury of being able to examine the DNA of both. In a similar way we know that some humans, primarily Europeans have a few % of Neandertal DNA, indicating cross breeding between the two species in Europe. This conclusion is possible because some Neandertal fossils contain enoough residual DNA for analysis.

Thanks a lot; much appreciated. I see the point. This means that if I want to conduct tests to confirm such relations, I need to fully understand all the surrounding concepts. I hoped for a shortcut, i.e. single test (concept) such as DNA that makes the results available. I will invest as much time as needed as soon as possible.

21 hours ago, 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.

Hi SJ, many thanks for your contribution. When I first read this particular reply, I thought I was done. But then, I read @Moontanman comment on this. 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?

19 hours ago, Area54 said:

There is a 2004 study in Italy into the origin of black wolves. Occurrence of black wolves in the Northern Apennines, Italy . (https://link.springer.com/article/10.1007/BF03192528) Unfortunately the article itself is behind a paywall, but here is the abstract:

The occurrence of black-coated individuals in wolfCanis lupus Linnaeus, 1758 populations is not surprising itself, but their presence in populations recovering from a severe numerical decline has been considered a possible sign of crossbreeding with the domestic dog. In the northern Apennines (Italy), black wolves occur at a non-negligible frequency. In a 3300 km² area, 22% of wolves observed and 23% of all dead wolves found were represented by animals with a completely black coat. One ‘black’ wolf belonging to the studied population was analysed by a set of microsatellite loci, and no trace of hybridization was found in its ancestry. This result induced us to consider the occurrence of a black phenotype in this area possibly derived from a natural combination of wolf alleles in coat colour determining genes, and not necessarily as the result of crossbreeding with the domestic form.

And this may be the study that Moontanman was aware of through the documentary. "Molecular and Evolutionary History of Melanism in North American Gray Wolves" And the good news is that the complete article is freely available. In the meantime here is the abstract.

Morphological diversity within closely related species is an essential aspect of evolution and adaptation. Mutations in the Melanocortin 1 receptor (Mc1r) gene contribute to pigmentary diversity in natural populations of fish, birds, and many mammals. However, melanism in the gray wolf, Canis lupus, is caused by a different melanocortin pathway component, the K locus, that encodes a beta-defensin protein that acts as an alternative ligand for Mc1r. We show that the melanistic K locus mutation in North American wolves derives from past hybridization with domestic dogs, has risen to high frequency in forested habitats, and exhibits a molecular signature of positive selection. The same mutation also causes melanism in the coyote, Canis latrans, and in Italian gray wolves, and hence our results demonstrate how traits selected in domesticated species can influence the morphological diversity of their wild relatives.

Note that the conclusion here  (black wolves arose from interbreeding with dogs) contrasts with the conclusion in Italy (the black colouration arose independently).

Hi A54, very interesting. Really good on you what you have learnt by yourself in this scientific field. The only problem for me is that for fully understanding these papers, I need to be comfortable with the scientific terms. Unfortunately, in my case, this is only possible if I thoroughly study the basics of this field. On the other hand, could you please advise on the answer I asked SJ for?

[CharonY]

Just skimmed through the thread and I see two concepts being confused here a bit. The first is ancestry. I.e. direct line of descent as e.g. determined by paternity testing. Here, we look at very closely related individuals. It can be extended to populations though then it becomes more diffuse. In all cases it is contained to closely related groups but with sufficient genetic information we could build, with relatively high confidence, the relationship between individuals within a population. Standard techniques being used currently are based on a handful of genetic markers, so depending on method it will a varying degree of resolution.

Dogs are a subspecies of wolves. For all intents on purposes, they are the same species. However, we do know the timeline when dogs arose (as they are domesticated). However, in natural populations defining timelines for populations within a species is always problematic as there is usually a lot of genetic flow between populations (i.e. interbreeding). That makes classification and especially timing a very difficult proposition. 

When we talk about phylogeny, we are looking at relationship between species. Here, it is important to note that in most cases the different species arose from a common ancestor, which is usually not around anymore. I.e. existing (extant) species are not derived from each other and therefore are not the ancestor of each other.

With regards to how to reconstruct phylogenies, you will need to delve a bit into concepts of DNA, its mutation rate and population genetics a bit. In short, typically conserved sequences (e.g. genes or genetic loci that are found in all species under investigation) are compared. The basic assumption is that the farther they are apart, the more the sequences diverge. There is also the concept of molecular clocks where we can use the divergence as a means to estimate when the respective species split (though that is even trickier).

[Ali NasserEddine]

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

1 hour ago, CharonY said:

Dogs are a subspecies of wolves. For all intents on purposes, they are the same species. However, we do know the timeline when dogs arose (as they are domesticated). 

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

1 hour ago, CharonY said:

I.e. existing (extant) species are not derived from each other and therefore are not the ancestor of each other.

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.

1 hour ago, CharonY said:

There is also the concept of molecular clocks where we can use the divergence as a means to estimate when the respective species split (though that is even trickier).

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