Dr Alice Roberts: The Incredible Unlikeliness of Being

A Roberts. unlikeliness of being

About a month ago I started reading Prof Alice Roberts’ book ‘The Incredible Unlikeliness of Being’ and it certainly didn’t disappoint. I have seen many of Prof Roberts’ TV documentaries and have read one of her other books ‘The Incredible Human Journey’ and have always enjoyed their content. My own academic and personal interests include human evolution, the human body and subjects surrounding the natural sciences making Alice Roberts’ books and programmes deeply interesting.

I have meaning to read ‘The Incredible Unlikeliness of Being’ ever since I received the book last Christmas and I am very glad that I’ve finally got round to it. A large portion of the work published by Alice Roberts has surrounded the topic of human evolution and as that is the subject I studied as an undergraduate I was mostly familiar with the material and areas covered. However, her latest book goes back deeper into evolutionary history and discusses the evolutionary history of our bodies. This means looking at embryos, genes and the visible anatomy using the latest research in order to understand how we came to look like the way we do today.

Throughout the book there is amazing detail that is described in such a way that it is to understand, so even if you have a limited knowledge of anatomy you should be able to follow. There are also many illustrations, which were hand-drawn, that again assist to understand the processes and structures that are being discussed. Whilst reading this book I learnt so many things about our anatomy and our evolutionary history. Most of my knowledge surrounding evolution is focused on and around human evolution, with other primates and some other mammals for comparison but ‘The Incredible Unlikeliness of Being’ has definitely expanded my knowledge.

One thing that this book highlights for me is that we as human beings are not unique or incredibly special. We are a product of evolution and a great deal of luck that we even exist. For some this thought is terrifying and wrong – that we are special and that makes us better for it. I have totally the opposite opinion. The fact that we can see traits that give us a hint of our evolutionary history and that these traits can be seen in other organisms is amazing. However, from another point on view at a very individual level it is incredible that either you or me are here today. It is chance that a particular sperm met that particular egg to produce you and this story repeats itself at every level of our evolutionary history. The more I think about it more the mind boggles!

This is a great book that is well written and easy to both read and understand. I highly recommend it to anyone who has an interest in evolution, biology or anatomy.

 

A Brief Look at a DNA Analysis of Ancient Dogs of the Americas

 

Dog skull. (Image taken from www.angelfire.com)

Dog skull. (Image taken from www.angelfire.com)

Quite a while I wrote a couple of posts about the domestication of dogs including one about archaeological evidence and the origins of this domestication. Recently I came across an article that completed a DNA analysis of ancient dogs of the Americas (Witt et al. 2015). This study investigated the genomes of canine remains from three sites, in addition to a number of other sites from previous studies. 

From the study it was found that the most frequent haplotype was idential to those found in an ancient Siberian dog, making it a likely founding haplotype. Humans were first thought to cross to the Americas around 15 – 20 kya, with subsequent movements before the Bering Strait submerged about 10 – 11 kya. When these individuals came across to the Americas they also brought along their domesicated dogs, with the oldest remains dating to 10 kya BP (Witt et al. 2015). It is then thought that there was possibly admixture (breeding) between domesticated dogs and North American wolves due to shared or similar mitochondrial haplotypes. However, this could have also been a result of a seperate domestication events and Witt et al recommend that additional regions of the genome should be examined to establish the evolutionary history of these dogs.

Invesitgating the evolutionary history of the domesticated dog is not only interesting for the evolution of a species, but also because it may be used as a complemetory data source of human activity. The oldest canine remains suggest that the domestication of dogs could have started around 33,000 years ago. Due to a long period of domestication, along with different goups of people, some breeds of dog have different genes enabling them to survive depending on their environment. For example, wolves have only two copies of the genes that enable the ability to digest starch. However, it has been found that a correlation exisits between dog breeds that originate from a region of human agriculture posessing more copies of this gene then those dogs who were raised in an evniroment with no history of agriculture. The example provided by Witt et al (2015) states that the saluki, which derives from the Fertile Cresent, has 30 copies of the gene whilst the Siberian husky has only two genes (Freedman et al 2014).

Therefore collecting data on the domestication and genetics of canines can provide researchers with a complementary data source to study human population history.

 

Freedman, A. H. et al. Genome sequencing highlights the dynamic early history of dogs. PLoS genetics 10, e1004016 (2014).

Witt, K. E. et al. (2015) DNA analysis of ancient dogs of the Americas: Identifying possible founding haplotypes and reconstructing population histories. Journal of Human Evolution 79, 105-118,

Giant subfossil lemur graveyard discovered, submerged, in Madagascar

High resolution, in situ photographs of Aven subfossils. (Taken from Rosenberger et al. p. 3).

High resolution, in situ photographs of Aven subfossils. (Taken from Rosenberger et al. p. 3).

Yesterday my friend at work sent me this paper because she had heard of my interest in bones. This article features a graveyard – not of humans but of fossil lemurs and other fauna. An expedition of some flooded freshwater caves in Tsimanampetsotsa National Park, Madagascar was undertaken to investigate the paleontological potential of the caves.

On this preliminary investigation several species were identified including birds, reptiles, small mammals and large vertebrates and that this assemblage represents ‘a reasonable cross-section of the known extinct fauna found in the region of Tsimanampetsotsa National Park’ along with some species that are still living today. From this range of fauna discovered the most abundant were the giants lemurs and appears to be one of the most richest sites in Madagascar. 

As this expedition was conducted to explore the site no specific measurements or counts were made regarding the skeletal remains. However, future investigation may be able to shed light on past biodiversity in that area and the time period that they existed. I will try to keep an eye on for developments of this site in the future as it has great potential.

You can read the article here which also includes a video taken during a diving trip into the caves. 

Reference: Rosenberger, A. L. et al. Giant subfossil lemur graveyard discovered, submerged, in Madagascar. Journal of Human Evolution. [In press at time of writing].

Paleolithic Cave Art in Indonesia and Spain.

Dated rock art from Leang Jarie of hand stencils. image taken from Aubert et al. (2014) p.225.

Dated rock art from Leang Jarie of hand stencils. image taken from Aubert et al. (2014) p.225.

Earlier this month an article was published in Nature revealing some new evidence of Paleolithic cave art. The most famous and probably well known cave art is the Lascaux Caves in France with depictions of large animals spanning the cave walls. Plenty of other examples of palaeolithic art has been found in Europe, especially in France and Europe but what makes this most recent publication by Aubert et al (2014) is that this cave art is in Indonesia. However, this is not the only striking fact of this art, but more importantly the age of the art found to have have been created at least 40,000 years ago. This post will look at this art and how this discovery can provide an insight into human evolutionary history alongside other art found in Spain dating to the same time.

The cave art in Indonesia is located on the island Sulawesi and was first discovered in the 1950’s but was thought to be less than 10,000 years old. By using a dating technique using trace elements of uranium Aubert et al. established that they were in fact much older than this. This method uses calcite which forms in caves and over the paintings and therefore can identify a minimum age for the art. This method was also used in a previous study by Pike et al. (2012) who used the technique on cave art in the Southwest of Spain. What was remarkable that for some of the paintings found in the caves the minimum age of creation was 40,000 year ago. Before, I discuss what this could mean from a human evolutionary perspective I will look at the cave independently and discuss their findings.

Dated rock art from Leang Timpuseng of a pig-deer. Image taken from Aubert et al. (2014) p. 224

Fig. 1Dated rock art from Leang Timpuseng of a pig-deer. Image taken from Aubert et al. (2014) p. 224

The art at the Sulawesi caves included depictions of large animals and hand stencils. From 14 of these motifs 19 samples were taken at 7 different sites. From every sample 3-6 aliquot were acquired, one from under the pigment layer and at least two from above this layer. From this data it was found that an image of a pig-deer (figure 1) was dated to 35,400 years ago. The hand stencils (fig. 2) were even older with having a minimum age of 39,900 years old. These dates, add mentioned, are within the dates produced for oldest cave art found in Spain.

Dated rock art from Leang Jarie of hand stencils. image taken from Aubert et al. (2014) p.225.

Fig. 2 Dated rock art from Leang Jarie of hand stencils. image taken from Aubert et al. (2014) p.225.

The research conducted Spain took 50 samples from 11 cave sites using the methods discussed above. A variety of images were found and dated included a red dotted house, hand stencils and red circular disks (fig. 3). The horse was dated to 22,000 years ago and one hand stencil days to 24,200 years ago and another to 37,300 years. However the oldest dated was recorded from of the red disks to 40,800 years old.

The Techo de los Polícromos, Altamira Cave, showing the red spotted outline horse (sample O-53) and the larger red claviform-like symbol (sample O-50). image taken from Pike et al. (2012) p. 1411.

Fig. 3 The Techo de los Polícromos, Altamira Cave, showing the red spotted outline horse (sample O-53) and the larger red claviform-like symbol (sample O-50). image taken from Pike et al. (2012) p. 1411.

These similar days from Spain and Indonesia provide an interesting discussion point in the story of human evolution. Although the techniques and images are similar in different locations and date to a similar time it cannot be said whether they derived independently or whether they were a part of an older cultural repertoire.

I think this discovery in Indonesia is incredible and when combined with the data from Spain it just adds to the remarkable story of human evolution. I also think that it important to remember that events occurred outsider of Europe and currently we have a very euro centric view of the world. Discoveries like these help to remind us that this isn’t the case and that in order to get a complete and accurate view of human evolution research across the world must occur.

 

References

Aubert, M., A. Brumm, et al. (2014). “Pleistocene cave art from Sulawesi, Indonesia.” Nature 514(7521): 223-227.

Pike, A. W. G., D. L. Hoffmann, et al. (2012). “U-Series Dating of Paleolithic Art in 11 Caves in Spain.” Science 336(6087): 1409-1413.

Roebroeks, W. (2014). “Archaeology: Art on the move.” Nature 514(7521): 170-171.

A Look into Cat Genomics

Image of an Abyssinian cat. image taken from http://proxvost.info/ln/en/short-haired/abyssinian_cat.php

Image of an Abyssinian cat, the first to have their genome sequenced. Image taken from http://proxvost.info/ln/en/short-haired/abyssinian_cat.php

As a part of my Skull of the Month series I always try to find out a bit about the chosen animal’s evolutionary history. This is because I studied human evolution at university and want to broaden my knowledge of other animals. This month’s skull is the domestic cat, an animal I am familiar with in everyday terms but not on a scientific one.

Previously I have written about the domestic dog and their history. To be honest I already had a general idea about the dog’s past as I also have always had an interest in wolves. It is also evident that the domestication of dogs came about through hunting and guarding with human settlements.  The cat, however, is a completely different story. Of course I know that the domestic cat is related to the other big cats around the globe but that’s as far as it went and with regards to cat domestication I didn’t even know where to start! However, a quick search on Google Scholar identified the perfect article to start off with. This was a review article from Cell Press entitled ‘State of Cat Genomics’ by O’Brien et al. (2012). This article takes a look at some of the progresses made within the field of genomics relating to the domestic cat including how the genomes have been sequenced and what they can tell us about the evolutionary history and domestication of the humble cat.

The modern cat was selected as one of 24 mammals to have their entire genome sequenced in 2005 by the National Human Genome Research Institute. The first cat to have this done was an Abyssinian cat called Cinnamon. By examining genomes of other mammals advancement into human, and also animal, health can be made. Table 1. (p.269) in the article provides some examples of the used for cat genomes.

 In order to reconstruct the origins if the domestic cat a robust molecular phylogeny had to be made. To do this the 35 cat genes were selected and sequenced in all cat species. The earliest identified predecessor of cats lived in Europe during the Miocene and was Pseudaelurus andgave rise to the Asian ancestor of modern cats ~11 million years ago (Mya). The first split from this ancestor cat produced the Panthera genus (containing lions, tigers and leopards, around 10.8 Mya.  A second split in Asia produced more species which speciated and moved into South East Asia. A further split around 6-10 Mya produced an inter-continental migration into Africa. This was achieved by a fall in sea levels producing a land bridge across the Red Sea. This also occurred across the Bering Straits to Alaska permitting movement into these new continents. As sea levels raised these land bridges were lost which separated the continents allowing for evolution of new species of cat that we are familiar with today. During the Pliocene more migrations occurred between America and Asia and into South America as the sea levels continued to rise and fall over time.

Molecular phylogeny of Felidae. Image taken from article, fig. 2 p. 273.

Molecular phylogeny of Felidae. Image taken from article, fig. 2 p. 273.

 From the genetic data it has been established that the origins of cats was founded in Asia. However, where and when did the modern cat that is so familiar today come from? By conducting a phylogeographic study using a large data set of domestic and wildcats from Asia, Europe and Africa the evidence pointed to the Near East. It was found that a large proportion of domestic cats across the globe possess genotypes which are indistinguishable from classes that have been identified in subspecies of wildcats cats in the Near East. In addition to this a discreet population of wildcats was found in the Near East using an alternative analysis. This evidence suggests that the founding population for the world’s domestic cats came from this area.

 Aside from the genetic data archaeological remains also support the theory of the origins of cat domestication residing in the Near East. The remains for cats and humans were found together and dated to 9,500 years ago. This coincides with the first agricultural settlements in the Fertile Crescent, an area of fertile land between the Arabian desert and the mountains of Armenia.  These settlements also date to 10,000 years ago, providing compelling evidence that humans and cats were in the same place at the same time. 

 A theory as to why cat domestication arose is that the cats may have been used to farmers in the removal of rodents. It is known today that cats are sometimes bought and kept in order to rid mice and rats of land. However, in the late 18th, early 19th Century cats were started to be selectively bred to produce fancy breeds. This is in stark contrast to the domestic dog that was bred into a number of sizes and types to assist with hunting. Most importantly these cats can be traced back to those in the Near East. Interestingly all 68 breeds of the international Cat Association and the American Cat Fanciers can trace their origins to the Fertile Crescent and human civilisation. 

 From this one article I have already learnt so much more about the domestic cat. Their history is really interesting, and I bet that there even more to find out. It’s just a shame that they are considered to be the only group of the Felidae species that is not currently endangered or threatened. 

 

O’Brien, S. J., W. Johnson, et al. (2008). “State of cat genomics.” Trends in Genetics 24(6): 268-279.

What do you do on a Friday Evening?! Apparently I Learn About Duck Sexual Organs!

A cyanide and happiness cartoon originally viewed and reblogged from http://zombiesandporn.tumblr.com/post/83126433755/collide-with-the-pie-categoryfourkaiju

A Cyanide and Happiness cartoon originally viewed and re-blogged from Attack on Tardis‘s tumblr

So I just finished watching a film and was just looking through my tumblr when I cam across the cartoon above. I had guessed that it was referring to a ducks penis but curiosity and wanting to check the facts got the better of me. A quick Google search brought up an article from sciencedaily.com which discussed how ducks have competing sexual organs. The male duck has a large corkscrew shaped penis and females have corkscrew spiral shaped vagina. However the shape of the females genitalia makes copulation difficult and may be a result of attempting to elude forced copulation.

So on a lazy Friday night in I learnt 1) male ducks have a phallus (apparently most birds don’t which I didn’t know!). 2) Male ducks have corkscrewed shaped penises and 3) female ducks anatomy may have evolved in such a way to evade forces copulation. All because of a funny cartoon on tumblr! I sometimes wonder how my brain works.

The information for the science daily article originally came from a paper in Proceedings of the Royal Society B and is entitled ‘Explosive eversion and functional morphology of the duck penis supports sexual conflict in waterfowl genitalia.‘ I haven’t read the paper myself but I will do, but maybe another day!

 

The Evolution of Frugivory in the Bat family of Phyllostomidae

Summary phylogeny of 150 species of phyllostomid bats illustrating diversity in lineages and morphology among subfamilies.Image and caption taken from Dumont et al. article.

Summary phylogeny of 150 species of phyllostomid bats illustrating diversity in lineages and morphology among subfamilies.Image and caption taken from Dumont et al. article.

This article attempts to address the issue: why do some lineages consist of many species with a large degree of variation where as others have only a few species, with little variation? By using phylogenetic methods this question is investigated using large datasets on bats. This is because the order Chiroptera is one of the most diverse families of mammals and includes the family Phyllostomidae, or the leaf-nosed bat. These bats are from the New World and consist of nearly 200 species however, only include 10 species of their closest relatives were produced in the same time span. The difference between these families is that the majority of bats eat insects whilst the Phyllostomidae have a more diverse diet which includes nectar, fruit, frogs and lizards.

By looking at diet, cranial morphology and the bite force the authors were able to test the hypothesis ‘that the evolution of frugivory and a skull phenotype that improved biting performance within this feeding habit is associated with increasing diversification rates in this family’ (Dumont e al 2012). In order to test this they analysed thousands of evolutionary trees spanning over 150 species and measuring 600 bat skulls bellowing to 85 species. These bite force of 500 bats from 39 species was also tested.

The results from the research found that a new skull shape in these New World bats emerged about 15 million years ago, leading to an explosion of many new bat species. This skull was lower and broader allowing for high bite forces to be produced, even for small bats. This increase in bite force is needed in order to process hard fruits. As a new ecological niche could be exploited and as the new skull shape evolved there was an increase in the birth rate of new species.

These ‘morphological innovations’ allows for resources to be exploited and therefore an increase in the evolution of new species. This new skull phenotype led to the evolution of frugivory and a higher degree of speciation within the phyllostomids. This is a lovely example of how new species can arise in the response to exploiting a new resource.

 

References:

University of Massachusetts at Amherst. “Studying bat skulls, evolutionary biologists discover how species evolve.” ScienceDaily. ScienceDaily, 28 November 2011. <www.sciencedaily.com/releases/2011/11/111123133520.htm>.

 

Elizabeth R. Dumont, Liliana M. Dávalos, Aaron Goldberg, Sharlene E. Santana, Katja Rex, and Christian C. Voigt (2012) ‘Morphological innovation, diversification and invasion of a new adaptive zone’ in Proc. R. Soc. B 279 1734 1797-1805; published ahead of print November 23, 2011, doi:10.1098/rspb.2011.2005 1471-2954