Currently there is a catastrophic outbreak of Ebola happening in West Africa. Over 1700 infections have been recorded with nearly 1000 deaths, making it the deadliest outbreak of ebola known. Infection results in a hemorrhagic fever, which starts out a bit like the influenza, but can result in bleeding from mucous membranes, organ failure, and ultimately death. But what is Ebola?
Ebola is a Filovirus. Filoviruses are a small group of viruses only known to infect mammals. They are so named because of their filamentous shape. They have tiny genomes, only ~19,000 base pairs in length, containing only seven protein coding genes and two regulatory regions. By contrast, the human genome is over 3 billion base pairs, contains around twenty thousand genes and has innumerable (by which I mean as yet unnumbered regulatory regions). Because of ebola’s simplicity, (as with all viruses), it cannot reproduce without commandeering the cellular machinery of its hosts. In the words of Cormac McCarthy, These anonymous creatures… may seem little or nothing in the world. Yet the smallest crumb can devour us.
This is a guest post by Daniela Vergara, a postdoctoral researcher studying the genomic architecture of hybrid species of sunflowers and Cannabis in Nolan Kane’s Lab at the University of Colorado, Boulder. Daniela also blogs about science at A Ciencia Abierta. Check out her blog for a spanish version of this post.
Cannabis is definitely a cool plant. It has fun names like matanuska thunderfuck, jesus OG or trainwreck and it has been trendy among humans for a very long time (humans have utilized it for thousands of years). Despite this long history, and the fact that Cannabis is the most widely used recreational drug in the world , the genomics and the general the biology of these plants have only been partially studied. At the Cannabis Genomic Research Initiative (CGRI) at the University of Colorado Boulder we want to study this genus of plants for several reasons, including: (i) its medical significance, (ii) its importance in the biofuel, fiber, oil, textile and food industries, (iii) its long co-evolutionary relationship with humans as an ancient crop, and (iv) in general, because it is an exciting emerging study system in evolutionary biology.
Why should evolutionary biologists be excited about studying Cannabis?
In my part of North America, spring is finally underway after a long slog of a winter. The trees lining the streets of my Minneapolis neighborhood are lacy-green with budding leaves, flowerbeds all over the University of Minnesota campus are yellow and red and pink with daffodils and tulips, and violets are popping up in the edges of lawns everywhere I look.
Of course, all of this colorful display isn’t for my benefit. Showy flowers are an adaptation to attract animal pollinators. Some flowers are quite precisely matched to a single species of pollinator, but most flowers have lots of visitors. These less specialized flowers are still adapted for their attractive function, though—and this is the origin of pollination syndromes.
You know the type. Big, brown eyes. Cute, little nose. Long, striped tail.
Tamias amoenus canicaudus, Steptoe Butte, WA, photo: Noah M Reid
Chipmunks are adorable and one of the more easily viewed yet still kind of exotic North American mammals (in my opinion). I worked on red-tailed chipmunks for my Master’s degree at the University of Idaho with Jack Sullivan. Sullivan (et al.) just published a review of all the chipmunk research that’s taken place in his lab over the past 10 years or so. Central to the review is the concept of divergence with gene flow (DGF), but let’s start with some back story.
Figure 4 from Tehrani 2013. The result of a network analysis among fairy tales. The large number of well spaced network connections from the East Asian group is suggestive of blending between the other two major groups.
In a pretty interesting example of cross fertilization between scientific disciplines, a recently published paper by Jashmid Tehrani uses phylogenetic methods borrowed from evolutionary biology to construct an “evolutionary tree” of fables related to Little Red Riding Hood.
Tales typical of Riding Hood are found mostly in Europe, but a series of stories sharing some features are found in Africa (involving an Ogre) and East Asia (The Tiger Grandmother). These have sometimes been considered to be part of the Riding Hood group, but there has been debate over whether or not they actually belong to another, closely related group found in Europe and the Middle East known as The Wolf and the Kids.
This week we have a guest post by Jessica Oswald a graduate student at the Florida Museum of Natural History at the University of Florida. She works on the biogeography of neotropical birds using fossil, ecological, and molecular genetic data.
As an avian paleontologist, digging through fossils is to me like birding with a time machine. These fossils help us paint a picture of where modern forms came from and how different ancient species were from modern-day birds, especially intermediate forms. These outliers and in-betweeners are interesting because they hint at all sorts of morphological diversity that we don’t even know or expect, and give us a window into the past and how different diversity, communities, and climatic conditions and landscapes were from what we are familiar with today.
This paper (Ksepka et al. 2013) on an early bird in the Swift-hummingbird clade does both of these things by exhibiting an odd morphology that we don’t see in modern birds, and helps us understand how the uniquely specialized wing shapes in modern swifts and hummingbirds arose from their common ancestor.
Members of the order Apodiformes: treeswifts (Hemiprocnidae), true swifts (Apodidae), and hummingbirds (Trochilidae), are aerial marvels. Swifts are able to reach the highest speeds during level flight (Chantler 1999) and hummingbirds are well known for their hovering abilities and their sideways and backward flight. Swifts and hummingbirds, while sharing the same wing bone characteristics, have different lengths of flight feathers, resulting in different wing shapes across the group, which allows them to perform their different aerial feats. Hummingbirds have shorter wings relative to their body size compared to swifts, resulting in their hovering abilities. These different wing shapes are well suited for their modern functions, but we have almost no fossils from this group, so we don’t know how the wing shapes diverged, or anything about the ecology of ancient species in this lineage.
It would seem that between the global hitchhiking of feral pigs with human migration, America’s absurd obsession with bacon and the possible emergence of pandemic influenza via recombination of human and porcine strains, the past, present and future of our civilization are inextricably linked to that of the domestic pig. With that in mind, let’s have a look at a recent paper on the evolutionary history of the genus Sus by Frantz et al. 2013.
Domestic pigs are in the family Suidae, which includes the babirusas, warthogs, the endangered pygmy hog (whose generic name is, Porcula, seems a likely candidate for America’s next tragic children’s cereal) and the domestic pig’s close relatives in the genus Sus. Depending on where you draw the lines, there are around 7 species in Sus. With the exception of the wild boar (Sus scrofa) their natural ranges are restricted to Southeast Asia west of Wallace’s Line. Extant species of Sus have diversified recently (sharing a common ancestor ~5 million years ago) and the species are all thought capable of producing viable hybrid offspring. Most species are restricted to single islands or island complexes in Southeast Asia (such as Borneo, Java and the Philippines). Previous phylogenetic estimates of the genus are in conflict over the relationships among species.