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DNA analysis reveals there are four distinct giraffe species, not one

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Re: DNA analysis reveals there are four distinct giraffe species, not one

#21

Post by Retric »

MustardTiger wrote: post #15
Retric wrote: post #11

Earlier quoted context omitted.

Genetically Brown and polar bears are subspecies not separate species. They have also had 3+X as many generations since the last ice age vs people.

People have been separated far longer than just since the ice age. And no, some people think brown bears and polar bears should be reclassified, others do not. As it stands, they are separate species. Take the 2 seconds to google basic information before posting incorrect things that are so easy to verify. Even if you reclassify them, it still supports my point: humans consist of several subspecies.

People also talk about Europe and Asia as separate despite being a contiguous landmass on the same plate. Genetically brown and polar bears can and in reality often do interbreed producing viable offspring and exchanging genetic information between populations.

Re: DNA analysis reveals there are four distinct giraffe species, not one

#22

Post by [deleted] »

MustardTiger wrote: post #15
Retric wrote: post #11

Earlier quoted context omitted.

Genetically Brown and polar bears are subspecies not separate species. They have also had 3+X as many generations since the last ice age vs people.

People have been separated far longer than just since the ice age. And no, some people think brown bears and polar bears should be reclassified, others do not. As it stands, they are separate species. Take the 2 seconds to google basic information before posting incorrect things that are so easy to verify. Even if you reclassify them, it still supports my point: humans consist of several subspecies.

[deleted]

Re: DNA analysis reveals there are four distinct giraffe species, not one

#23

Post by Scarblac »

kristofferR wrote: post #19
bcraven wrote: post #8

Earlier quoted context omitted.

https://en.wikipedia.org/wiki/Species_problem The word "Species" is mixed up in all manner of biological and sociological turmoil. I was even of the impression that becuase of DNA sequencing the term is falling out of favour amongst researchers.

Would DNA sequencing just make it easier to distinguish different species (like in this case) from each other instead of making the term more problematic?

It's all a gray area, the distinction between two individuals being the same or different species is pretty arbitrary.

DNA sequencing just replaces it with more accurate things (say the amount of DNA two individuals have in common, estimates of how long ago the last common ancestor lived, etc).

Re: DNA analysis reveals there are four distinct giraffe species, not one

#24

Post by Retric »

dalke wrote: post #18
Retric wrote: post #11

Earlier quoted context omitted.

Genetically Brown and polar bears are subspecies not separate species. They have also had 3+X as many generations since the last ice age vs people.

They are "generally classified as separate species", says https://en.wikipedia.org/wiki/Polar_bear#Taxonomy_and_evolut... : > A comparison of the nuclear genome of polar bears with that of brown bears revealed a different pattern, the two forming genetically distinct clades that diverged approximately 603,000 years ago,[25] although the latest research is based on analysis of the complete genomes (rather than just th…

Most brown bears have about 2 percent genetic material from polar bears, but one population, the ABC Islands bears has between 5 percent and 10 percent polar bear genes, indicating more frequent and recent mating.

Ed: I don't disagree with what you're saying, I just don't think it's relevant to discussions of DNA. We can call Pluto a potato, does not change anything. As to classification the trend is clearly to call them the same species we just need to let the old scientists die off ;)

Re: DNA analysis reveals there are four distinct giraffe species, not one

#25

Post by dalke »

MustardTiger wrote: post #16
dalke wrote: post #13

Earlier quoted context omitted.

The paper is about species , not subspecies . The paper says: > Thus, population genetic, phylogenetic, and network analyses of nuclear sequences demonstrate that the giraffe is genetically well structured into four distinct species. This is consistent with divergence times of 1.25 to 2 million years ago (mya) among the four clusters (Figure 3C). That genetic isolation is 100x longer than the human migration to the A…

>The paper is about species, not subspecies. And my reply is about subspecies, and our refusal to apply the same standards we apply to other animals to ourselves. I do not understand your confusion. >Humans do not meet the phylogenetic criteria which justifies the use of "subspecies" We have greater genetic difference between races than ANY example of subspecies in existence. I am very aware that a large group of peo…

Yes, my complaint is that you are highjacking an article on species differentiation in giraffes to talk about purported human subspecies.

No, we emphatically do not have that high of a genetic difference. Quite the opposite. The diversity in human genetics is relatively small compared to other species. For example, quoting http://www.nature.com/ng/journal/v27/n2/full/ng0201_155.html :

> The extent of DNA sequence variation of chimpanzees is several-fold greater than that of humans[1]. It is unclear, however, if humans or chimpanzees are exceptional among primates in having low and high amounts of DNA sequence diversity, respectively. To address this, we have determined approximately 10,000 bp of noncoding DNA sequences at Xq13.3 (which has been extensively studied in both humans and chimpanzees[1, 2]) from 10 western lowland gorillas (Gorilla gorilla gorilla) and 1 mountain gorilla (Gorilla gorilla beringei; that is, from 2 of the 3 currently recognized gorilla subspecies[3]), as well as 8 Bornean (Pongo pygmaeus pygmaeus) and 6 Sumatran (Pongo pygmaeus abelii) orang-utans, representing both currently recognized orang-utan subspecies[4]. We show that humans differ from the great apes in having a low level of genetic variation and a signal of population expansion.

I'll repeat that last line for emphasis: "humans differ from the great apes in having a low level of genetic variation"

The paper I linked to previously specifically compares the differences in DNA between chimpanzee subspecies to any putative human subspecies.

> We know that there is human geographical variation, but does this infraspecific diversity reach a threshold that merits the designation 'subspecies', as is true with chimpanzees[14]? ...

> The within- to between-group variation is very high for genetic polymorphisms (approx85%; refs. 16,17). This means that individuals from one 'race' may be overall more similar to individuals in one of the other 'races' than to other individuals in the same 'race'. This observation is perhaps insufficient[18], although it still is convincing because it illustrates the lack of a boundary. Coalescence times[19, 20] calculated from various genes suggest that the differentiation of modern humans began in Africa in populations whose morphological traits are unknown; it cannot be assumed from an evolutionary perspective that the traits used to define 'races' emerged simultaneously with this divergence[15]. There was no demonstrable 'racial' divergence. ...

> Race' is a legitimate taxonomic concept that works for chimpanzees but does not apply to humans (at this time). The nonexistence of 'races' or subspecies in modern humans does not preclude substantial genetic variation that may be localized to regions or populations.

DNA doesn't lie. Humans lie, or are mistaken. Please demonstrate that you are not mistaken, and tell us the source of your statement that "We have greater genetic difference between races than ANY example of subspecies in existence".

What are the two most distinct human subspecies, and what is their level of DNA similarity? How does that compare to the difference in chimp subspecies?

Re: DNA analysis reveals there are four distinct giraffe species, not one

#26

Post by wodenokoto »

guessmyname wrote: post #20

Off topic — How do I click the links at the bottom of this website? EDIT: To clarify, as some people thought this was a stupid question... Every time I scroll down to click one of the links the website scrolls my browser back up and loads a new article below the one I was reading. I don't want to read more articles, I want to click the links at the bottom of the website!!! I was not asking if the links work, they pro…

they work for me

Re: DNA analysis reveals there are four distinct giraffe species, not one

#28

Post by adekok »

Retric wrote: post #5
MustardTiger wrote: post #4

Earlier quoted context omitted.

The context does not contradict that statement. Every single measure used on every other animal would at minimum place humans in several subspecies. But we do not apply the same standards to ourselves for political reasons.

Humans have not really had enough time as independent populations to diverge much. The north american land bridge disappeared ~14,500 years ago so only ~14,000 years as separate populations. African > Eurasia had regular exchanges as they where within relatively short walking distances.

> ~14,000 years as separate populations.

Perhaps even less.

http://www.andrewcollins.com/page/articles/romanbust.htm

There was at least some contact between North America and Europe, close to 2K years ago.

Re: DNA analysis reveals there are four distinct giraffe species, not one

#29

Post by saynsedit »

MustardTiger wrote: post #16
dalke wrote: post #13

Earlier quoted context omitted.

The paper is about species , not subspecies . The paper says: > Thus, population genetic, phylogenetic, and network analyses of nuclear sequences demonstrate that the giraffe is genetically well structured into four distinct species. This is consistent with divergence times of 1.25 to 2 million years ago (mya) among the four clusters (Figure 3C). That genetic isolation is 100x longer than the human migration to the A…

>The paper is about species, not subspecies. And my reply is about subspecies, and our refusal to apply the same standards we apply to other animals to ourselves. I do not understand your confusion. >Humans do not meet the phylogenetic criteria which justifies the use of "subspecies" We have greater genetic difference between races than ANY example of subspecies in existence. I am very aware that a large group of peo…

Physical difference is not the same thing as genetic difference. Humans may subjectively look very different but genetically humans aren't very different. This is empiracle fact. Stop living in the 19th century.
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