Thursday, 11 June 2015

Ice Age Camels Give Creationists The Hump

North American Western Camel (artist's impression)
Ice age camel DNA discovered in Canada change theories on species | World news | The Guardian

Here we have a good example of how our understanding of DNA and the fact that evolution occurs at the genetic level, is informing biological research. It perfuses this paper concerning camel evolution and how the extinct North American Western Camel was related to the Asiatic camels, the Bactrian camel and the dromedary, and to the South American llamas, guanacos, alpacas, and vicuñas.

Based on morphology of fossil bones, it had been thought that the Western Camel was a giant llama. That view has now been disproved; it was a sister species of the Asiatic camels.

The proper, scientific definitions of evolution is of course, "change in allele frequency over time", a definition you will rarely if ever find in a creationist website or book because that isn't easy to attack and can easily be seen to happen in response to natural selection and genetic drift, so doesn't comply with the creationist anti-science, anti-evolution rhetoric. Even creationists find it hard to argue that something you can see isn't there and a process you can watch doesn't happen and has never been seen, so they need to attack a parody and rely on scientific illiteracy and desperation for confirmation of existing bias to do their work for them.

What this paper shows is that earlier taxonomies from before DNA sequencing and analysis became available, and based on morphology, didn't always show accurate relationships at the detailed level. Obviously, based on morphological evidence, the camels, including the Western Camel of Canada and Alaska are related to the South American camelids but the details of how exactly weren't clear. Biologists were aware that convergent evolution, for example, could lead unrelated species to look superficially similar but, before DNA evidence, there was no sure way to tell if they were looking at evidence of convergence or evidence of kinship.

The camelids are believed to have evolved in North America with one branch moving north towards the Canadian Arctic, becoming a tundra species, adapted to snowy conditions, and eventually migrating across Beringia into Asia, and another branch migrating down the Panama Isthmus to South America to become a montane species in the Andes. What was uncertain was whether the Western camel was a relative of the species that went south or the one that went west into Asia.

Now DNA recovered from fossil bones recovered during strip-mining of permafrost have closed that gap.

Abstract

Recent advances in paleogenomic technologies have enabled an increasingly detailed understanding of the evolutionary relationships of now-extinct mammalian taxa. However, a number of enigmatic Quaternary species have never been characterized with molecular data, often because available fossils are rare or are found in environments that are not optimal for DNA preservation. Here, we analyze paleogenomic data extracted from bones attributed to the late Pleistocene western camel, Camelops cf. hesternus, a species that was distributed across central and western North America until its extinction ~13,000 years ago. Despite a modal sequence length of only ~35 base pairs (bp), we reconstructed high-coverage complete mitochondrial genomes and low-coverage partial nuclear genomes for each specimen. We find that Camelops is sister to African and Asian bactrian and dromedary camels, to the exclusion of South American camelids (llamas, guanacos, alpacas, and vicuñas). These results contradict previous morphology-based phylogenetic models for Camelops, which suggest instead a closer relationship between Camelops and the South American camelids. The molecular data imply a Late Miocene divergence of the Camelops clade from lineages that separately gave rise to the extant camels of Eurasia. Our results demonstrate the increasing capacity of modern paleogenomic methods to resolve evolutionary relationships among distantly related lineages.

Genomic data from extinct North American Camelops revise camel evolutionary history
Peter D. Heintzman, Grant D. Zazula, et. al.
Molecular Biology and Evolution (2015) doi: 10.1093/molbev/msv128

We now know that the North American Western Camel which went extinct about 13,000 years ago, was a sister species of the Asiatic camels. The adaptations which were to prove so useful on the soft sands and dry conditions of first Central Asia, then the Arabian and African deserts as beast of burden for humans from about 1000 BCE, evolved on the Canadian tundra for snow and long periods of below freezing conditions.

As the authors say, "our results demonstrate the increasing capacity of modern paleogenomic methods to resolve evolutionary relationships among distantly related lineages", and again we see a developing new science not only failing to cast any doubt on the Theory of Evolution but reinforcing and confirming it and showing that ancient DNA, when it can be recovered, is exactly what we would expect of it if evolution is true.

The science of biology and biological relationships only makes any sense in the context of genetic evolution. For some reason, creationists can never explain why the DNA evidence from ancient sources such as this, always support the theory that modern species evolved out of earlier ones by a process of change in allele frequency. Why would an intelligent designer design species destined for extinction and design them in such a way that they look exactly as we would expect if they weren't designed, but evolved?

Is the 'Intelligent Designer' trying to make us think it doesn't exist?

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