Saturday, 10 September 2016

Another Big Problem For Creationists

Multi-locus Analyses Reveal Four Giraffe Species Instead of One: Current Biology

If only they were little less disingenuous and arrogantly certain, you could almost feel sorry for creationists. Just when they're settling down to feel smugly self-satisfied that they've invented a workaround for all the evidence that evolution fully explains biodiversity without involving their imaginary friend science comes up with another paper that illustrates the disingenuous fraud of this workaround. Their workaround was to deliberately misrepresent the terms 'macroevolution' and 'microevolution' as they are used by science.

Creationists have recently fallen back from their previous barricade of simply insisting that evolution simply doesn't happen, unable to resist the masses of evidence that it can and does and has been seen to happen. They are now trying to mount a stand around a misrepresentation of the term 'macroevolution', claiming that evolution happens and happens the way biologists describe it, but it only happens within a species and can never do more than produce variation, varieties and subspecies. It can never produce a new species because that would be 'macroevolution' which is some mysteriously different process altogether which is deemed impossible for some mysterious reason.

Distribution and Sampling Locations of Different Giraffe Subspecies in Africa

(A) Distribution ranges (colored shading) provided by the Giraffe Conservation Foundation [7]*, plotted on a map of Africa (http://www.naturalearthdata.com/). Circles represent sampling locations; for coding, see Figure 2.

(B) Enlarged view of the South Sudan region. Note that the samples of the putative Nubian giraffe were taken west and east of the Nile River.
*For reference see original paper.

© 2016 Elsevier Ltd. Published by Elsevier Inc. All rights reserved. Open access.
A week or so ago, before this paper on giraffe evolution and taxonomy was published, any self-respecting creationists would have been perfectly happy with there being several subspecies of giraffe and would have waved aside this evidence of their evolution and relationships to one another with the claim that this was entirely consistent with their invisible friend having made a giraffe which then diversified over time (just a few thousand years!) into all the different subspecies. No problem at all with natural selection being the cause of regional variation as it acted to change the frequency of different alleles in the different populations, just as evolutionary biology says. Where they would have fallen silent was over the evidence that it was an evolutionary arms race that resulted in a long neck because evolutionary arms races undermine their concept of intelligence-driven evolution, but that's a different matter.

Now, however, they have to explain how that process suddenly changed into something else and became retrospectively impossible because biologists have now shown that these are not regional varieties or subspecies at all, but four different species which can be shown to form a cladistic tree showing diversification from a common ancestor. In effect, geneticists have shown that giraffes long ago progressed beyond varieties and beyond subspecies even, to the point at which barriers to hybridization have led to effective gene-pool isolation, so meeting the definition of new species.

Highlights
  • Four genetically distinct giraffe clusters suggest separation into four species
  • This is the first study using nuclear sequences and analyzing the Nubian giraffe
  • Rothschild’s giraffe should be subsumed into the nominate Nubian giraffe
  • A giraffe survey genome produces valuable markers for phylogenomic analyses

Summary
Traditionally, one giraffe species and up to eleven subspecies have been recognized [ 1 ]*; however, nine subspecies are commonly accepted [ 2 ]*. Even after a century of research, the distinctness of each giraffe subspecies remains unclear, and the genetic variation across their distribution range has been incompletely explored. Recent genetic studies on mtDNA have shown reciprocal monophyly of the matrilines among seven of the nine assumed subspecies [ 3, 4 ]*. Moreover, until now, genetic analyses have not been applied to biparentally inherited sequence data and did not include data from all nine giraffe subspecies. We sampled natural giraffe populations from across their range in Africa, and for the first time individuals from the nominate subspecies, the Nubian giraffe, Giraffa camelopardalis camelopardalis Linnaeus 1758 [ 5 ]*, were included in a genetic analysis. Coalescence-based multi-locus and population genetic analyses identify at least four separate and monophyletic clades, which should be recognized as four distinct giraffe species under the genetic isolation criterion. Analyses of 190 individuals from maternal and biparental markers support these findings and further suggest subsuming Rothschild’s giraffe into the Nubian giraffe, as well as Thornicroft’s giraffe into the Masai giraffe [ 6 ]*. A giraffe survey genome produced valuable data from microsatellites, mobile genetic elements, and accurate divergence time estimates. Our findings provide the most inclusive analysis of giraffe relationships to date and show that their genetic complexity has been underestimated, highlighting the need for greater conservation efforts for the world’s tallest mammal.

An Angolan giraffe (G. giraffa angolensis) herd in Damaraland, NW Namibia.
Credit: Julian Fennessy
A Nubian giraffe (G. camelopardalis camelopardalis) in Murchison Falls NP, Uganda.
Credit: Julian Fennessy
Reticulated giraffe (G. reticulata) is in Samburu NP, Kenya.
Credit: Julian Fennessy
The scientific significance of this study is that it now raises the question of how and why this genetic isolation occurred in various locations across the range of the genus. It had been widely assumed that the ecological requirements were very similar across the range and the morphological and coat-pattern differences are minor. It also has implications for conservation because this is not a single species but four distinct species, two of which because of their low numbers are endangered.

It also illustrates how taxonomic classification is essentially an arbitrary process when applied not to living species but to an evolving diverging gene-pool over time.

For the creation industry the significance is profound. Suddenly, for reasons that have yet to be explained by creationists, a reassessment of the data and the publication of a research paper containing no evidence of any change of evolutionary mechanism, has revealed something that creationists must dogmatically dismiss as impossible. Last week it was not only possible but not even disputed; today it's become impossible. And yet nothing whatsoever has changed in the genetics of giraffes nor in their evolutionary history.

The only thing that has changed is better data and a modification in our understanding and the correct man-made classification biologists should now use. The fact that it took a detailed genetic analysis to determine that this was the case illustrates the smooth transition over time from subspecies to full species according to the man-made rules of taxonomy.

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