Creationism in Crisis - How Mammoths Evolved During The 700,000 Years They Lived in Siberia Prior To 'Creation Week'

Siberian woolly mammoth,
Mammuthus primigenius
(Reconstruction)

Woolly mammoths evolved smaller ears and woolier coats over the 700,000 years that they roamed the Siberian steppes | ScienceDaily

What could the authors of Gensis know about the fauna of Alaska when they thought Earth was a small, flat planet centered on the Canaanite hill country? They didn't even know much about the history of their close neighbours in Egypt and Mesopotamia, let alone the remote areas of Asia.

So, they were oblivious of the fact that there were woolly mammoths there and had been for some 700,000 years. This is why there are no mammoths in the Bible, nor their relatives, Asian and African elephants, for that matter. To Bronze Age Canaanite hill farmers these animals, and where they lived and the people who lived alongside them, simply didn't exist. So, they concocted tales which to us are ludicrously unrealistic, such as tales about a magic man magically making stuff from nothing with magic words, about 5,000 years before they were making the tales up, followed by an equally ludicrous tale of a genocidal flood about two thousand years later with two of all known species surviving for a year, sealed in a wooden box with no ventilation. They thought breath was something to do with 'life' and didn't know about oxygen or why the animals would have needed it, so didn't see anything wrong with a tale about hundreds of animals and 8 humans being sealed in a floating wooden box for a year.

But now, thanks to science, we know better and can see what they got wrong, and why they could not have privy to real scientific knowledge, or knowledge about real geography and history.

One of the things they got spectacularly wrong was the childish belief that all the animals around them and the planet they lived on, were all created in a few days and none of the animals had ancestors, because they didn't even know their domestic animals like goats, sheep, cattle, doves and pigs had all been selectively bred from wild ancestors.

And of course, they couldn't even have guessed that there were mammoths in Siberia which had been evolving there for 700,000 years until going extinct about 9,000 years earlier.

But a team of Swedish and Russian scientists, led by David Díez-del-Molino of the Centre for Palaeogenetics and Department of Zoology, Stockholm University, Stockholm, Sweden, has now examined the genomes of 23 woolly mammoths, including that of the oldest known remains from 700,000 years ago, and compared them to 28 genomes of modern Asian and African elephants, to gain an understanding of the evolution of this species of mammoth. Their findings are published in an open access paper in Current Biology and explained in a Cell press release (taken here from the copy in Science Daily):

A team of researchers compared the genomes of woolly mammoths with modern day elephants to find out what made woolly mammoths unique, both as individuals and as a species. The investigators report April 7 in the journal Current Biology that many of the woolly mammoth's trademark features -- including their woolly coats and large fat deposits -- were already genetically encoded in the earliest woolly mammoths, but these and other traits became more defined over the species' 700,000+ year existence. They also identified a gene with several mutations that may have been responsible for the woolly mammoth's miniscule ears.

We wanted to know what makes a mammoth a woolly mammoth. Woolly mammoths have some very characteristic morphological features, like their thick fur and small ears, that you obviously expect based on what frozen specimens look like, but there are also many other adaptations like fat metabolism and cold perception that are not so evident because they're at the molecular level.

David Díez-del-Molino, lead author
Centre for Palaeogenetics
Stockholm, Sweden

To identify genes that were "highly evolved" in woolly mammoths -- meaning they had accrued a large number of mutations -- the team compared the genomes of 23 Siberian woolly mammoth with 28 modern-day Asian and African elephant genomes.

Twenty-two of these woolly mammoths were relatively modern, having lived within the past 100,000 years, and sixteen of the genomes had not been previously sequenced.

The twenty-third woolly mammoth genome belonged to one of the oldest known woolly mammoths, Chukochya, who lived approximately 700,000 years ago.

Having the Chukochya genome allowed us to identify a number of genes that evolved during the lifespan of the woolly mammoth as a species. This allows us to study evolution in real time, and we can say these specific mutations are unique to woolly mammoths, and they didn't exist in its ancestors.

Professor Love Dalén, corresponding author
Professor of evolutionary genomics
Centre for Palaeogenetics, Stockholm, Sweden.

Not surprisingly, many genes that were adaptive for woolly mammoths are related to living in cold environments.

Some of these genes are shared by unrelated modern-day Arctic mammals.

We found some highly evolved genes related to fat metabolism and storage that are also found in other Arctic species like reindeer and polar bears, which means there's probably convergent evolution for these genes in cold-adapted mammals. We found that some of the genes that were previously thought to be special for woolly mammoths are actually variable between mammoths, which means they probably weren't as important

David Díez-del-Molino.

While previous studies have looked at the genomes of one or two woolly mammoths, this is the first comparison of a large number of mammoth genomes.

This large sample size enabled the team to identify genes that were common among all woolly mammoths, and therefore likely adaptive, as opposed to genetic mutations that might only have been present in a single individual.

Overall, the 700,000-year-old Chukochya genome shared approximately 91.7% of the mutations that caused protein-coding changes in the more modern woolly mammoths.

This means that many of the woolly mammoth's defining traits -- including thick fur, fat metabolism, and cold-perception abilities -- were probably already present when the woolly mammoth first diverged from its ancestor, the steppe mammoth.

However, these traits developed further in Chukochya's descendants.

The very earliest woolly mammoths weren't fully evolved. They possibly had larger ears, and their wool was different -- perhaps less insulating and fluffy compared to later woolly mammoths.

Professor Love Dalén.

More modern woolly mammoths also had several immune mutations in T cell antigens that were not seen in their ancestor.

The authors speculate that these mutations may have conferred enhanced cell-mediated immunity in response to emerging viral pathogens.

Working with ancient mammoth DNA comes with a slew of hurdles.

Every step of the way, things are a bit more difficult, from fieldwork, to lab work, to bioinformatics.

David Díez-del-Molino.

Apart from the field work, where we have to battle both polar bears and mosquitos, another aspect that makes this much more difficult is that you have to work in an ancient DNA laboratory, and that means that you have to dress up in this full-body suit with a hood and face mask and visor and double gloves, so doing the lab work is rather uncomfortable to put it mildly. I would like to highlight Marianne Dehasque, the second author of this paper, who did the herculean effort of performing lab work on most of these samples.

"We showed a couple of years ago that there was gene flow between woolly mammoths and the ancestors of Colombian mammoths, so that's something that we will need to account for because North American woolly mammoths might have been carrying non-woolly mammoth genes as well.

Professor Love Dalén.

All the mammoths whose genomes were included in this study were collected in Siberia, but the researchers hope to branch out and compare North American woolly mammoths in the future.

The results, which show a pattern of evolutionary adaptation for the cold climate of Siberia compared to that of the ancestral species, the steppe mammoth, including enhanced fat storage and metabolism, a woollier coat and smaller ears, and an enhanced immune system probably in response to new viral pathogens.

The researchers give more technical details in the published paper:

Graphical abstract

Highlights

• Genomes from 23 woolly mammoths and 28 extant elephants revealed adaptive differences
• Gene ontology suggested enrichment of mammoth genomic adaptations to cold environment
• Highly evolved genes included ones related to hair, skin, fat metabolism, and immunity
• Several key phenotypes appear to have evolved via heterochronous polygenic selection

Summary

Ancient genomes provide a tool to investigate the genetic basis of adaptations in extinct organisms. However, the identification of species-specific fixed genetic variants requires the analysis of genomes from multiple individuals. Moreover, the long-term scale of adaptive evolution coupled with the short-term nature of traditional time series data has made it difficult to assess when different adaptations evolved. Here, we analyze 23 woolly mammoth genomes, including one of the oldest known specimens at 700,000 years old, to identify fixed derived non-synonymous mutations unique to the species and to obtain estimates of when these mutations evolved. We find that at the time of its origin, the woolly mammoth had already acquired a broad spectrum of positively selected genes, including ones associated with hair and skin development, fat storage and metabolism, and immune system function. Our results also suggest that these phenotypes continued to evolve during the last 700,000 years, but through positive selection on different sets of genes. Finally, we also identify additional genes that underwent comparatively recent positive selection, including multiple genes related to skeletal morphology and body size, as well as one gene that may have contributed to the small ear size in Late Quaternary woolly mammoths.

Introduction

The evolution of mammoths (genus Mammuthus) was characterized by a series of morphological transitions defined by increasing specialization to life in cold high-latitude environments with open landscapes and grassy vegetation. This process culminated with the evolution of the woolly mammoth (Mammuthus primigenius), which originated in northeastern Siberia during the early stages of the Middle Pleistocene, approximately 700 thousand years ago (kya), and had become extinct by the onset of the Holocene (∼12 kya) across the vast majority of its range.^1,2

The woolly mammoth had a Holarctic distribution and inhabited terrestrial environments up to 80 degrees north, even during full glacial conditions.² Compared to both its extant elephant relatives as well as earlier members of Mammuthus, it was uniquely adapted to life in the high Arctic. The exceptional preservation of woolly mammoth remains recovered from permafrost deposits has enabled scientists to identify a wide range of morphological adaptations, such as thick woolly fur, small ears, short tail, and considerable fat deposits.³ Moreover, genetic analyses have hinted at previously unknown physiological adaptations to the Arctic environment, including genes related to thermal sensation and hemoglobin structure.^4,5,6 However, recent work has indicated that only a small subset of these adaptations was unique to the woolly mammoth compared to its million-year-old ancestors.⁷ Moreover, the small number of mammoth genomes sequenced to date has precluded confident identification of derived mutations that were fixed in the woolly mammoth lineage.

To address this, we here analyze a dataset comprising 22 Late Quaternary (the period encompassing the Late Pleistocene and Holocene) woolly mammoth genomes, an early Middle Pleistocene (700 kya) genome from one of the earliest known woolly mammoths,⁷ and 28 genomes from two extant elephant species. We identify genetic variants that had become fixed in the woolly mammoth lineage both prior to 700 kya, around the time that the woolly mammoth originated, and up to the final stages of the last glaciation (i.e., by 50 kya). Based on the woolly mammoth’s presence in the high Arctic for hundreds of thousands of years, we hypothesize that a marked proportion of these fixed variants are related to the unique morphology, fat storage and metabolism, thermosensation, and circadian rhythm of the woolly mammoth.

This work illustrates classic evolution as species diversify and evolve to suit conditions. There is a clear record of evolution in genes that benefit animals living in the harsh conditions of Siberia, interestingly paralleled in other species as examples of convergent evolution, even down to the evolution of a fur coat for insulation and smaller ears to reduce heat loss.

And it all happened gradually from at least 700,000 years before creationists think the universe existed because they believe tales made up by people who believed in magic but didn't know about Siberia or mammoths, to fill in the gaps in their knowledge, is real history, real science and real geography. The problem is, the people who made up those stories probably never intended them to be put in a book later declared to be the inerrant word of an omniscient creator god, by unscrupulous people with a vested interest in selling superstitions and quack cures for imaginary problems as an alternative to doing an honest job for a living.

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