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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

#11

Post by Retric »

MustardTiger wrote: post #6
Retric wrote: post #5

Earlier quoted context omitted.

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.

>Humans have not really had enough time as independent populations to diverge much There is no scientific basis for that claim. Many other animals have diverged less, in less time and are still separate subspecies. >African > Eurasia had regular exchanges as they where within relatively short walking distances. Interbreeding does not mean subspecies don't exist. Coyotes and wolves are totally separate species and the…

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.

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

#13

Post by dalke »

MustardTiger wrote: post #4
D4N_ wrote: post #3

Earlier quoted context omitted.

The quoted statement should be interpreted in the context of the study. Specifically, in the context that "species’ current ranges are not always delineated by geography". The genetic isolation of Native Americans was clearly a result of a geography.

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.

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 Americas. It's also 10x longer than the time to "Mitochondrial Eve" and about 8x longer than to "Y-chromosomal Adam".

Humans do not meet the phylogenetic criteria which justifies the use of "subspecies". See http://www.nature.com/ng/journal/v36/n11s/full/ng1455.html and many others. Quoting that reference:

> Modern human genetic variation does not structure into phylogenetic subspecies (geographical 'races'), nor do the taxa from the most common racial classifications of classical anthropology qualify as 'races' (Box 1). The social or ethnoancestral groups of the US and Latin America are not 'races', and it has not been demonstrated that any human breeding population is sufficiently divergent to be taxonomically recognized by the standards of modern molecular systematics. These observations are not to be taken as statements against doing research on demographic groups or populations. They only support a brief for linguistic precision and careful descriptions of groups under study. Terms and labels have qualitative implications.

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

#14

Post by MustardTiger »

louhike wrote: post #9
MustardTiger wrote: post #6

Earlier quoted context omitted.

>Humans have not really had enough time as independent populations to diverge much There is no scientific basis for that claim. Many other animals have diverged less, in less time and are still separate subspecies. >African > Eurasia had regular exchanges as they where within relatively short walking distances. Interbreeding does not mean subspecies don't exist. Coyotes and wolves are totally separate species and the…

The thing is we're talking about species here, not subspecies.

If you pay attention, we're talking about both. My replies have all very clearly been about subspecies, read my first post.

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

#15

Post by MustardTiger »

Retric wrote: post #11
MustardTiger wrote: post #6

Earlier quoted context omitted.

>Humans have not really had enough time as independent populations to diverge much There is no scientific basis for that claim. Many other animals have diverged less, in less time and are still separate subspecies. >African > Eurasia had regular exchanges as they where within relatively short walking distances. Interbreeding does not mean subspecies don't exist. Coyotes and wolves are totally separate species and the…

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.

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

#16

Post by MustardTiger »

dalke wrote: post #13
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.

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 people have a political agenda in denying this fact. But no amount of "we can get rid of racism by pretending races don't exist" will change basic facts. DNA does not lie.

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

#18

Post by dalke »

Retric wrote: post #11
MustardTiger wrote: post #6

Earlier quoted context omitted.

>Humans have not really had enough time as independent populations to diverge much There is no scientific basis for that claim. Many other animals have diverged less, in less time and are still separate subspecies. >African > Eurasia had regular exchanges as they where within relatively short walking distances. Interbreeding does not mean subspecies don't exist. Coyotes and wolves are totally separate species and the…

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 the mitochondria or partial nuclear genomes) of polar and brown bears, and establishes the divergence of polar and brown bears at 400,000 years ago.

> ... However, because neither species can survive long in the other's ecological niche, and because they have different morphology, metabolism, social and feeding behaviours, and other phenotypic characteristics, the two bears are generally classified as separate species.[29]

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

#19

Post by kristofferR »

bcraven wrote: post #8
thaumasiotes wrote: post #2

> The findings suggest that genetic exchange among the four species is rare, maybe even nonexistent. This genetic isolation defines them as distinct species, as opposed to subspecies. A bold, up-front assertion that Native Americans were in fact a distinct species from Europeans.

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?

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

#20

Post by guessmyname »

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 probably do, I am asking how do I "click them" if the website keeps moving the webview back up when I scroll to the bottom?

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