A new study released in the journal Microbiome (it’s open-access!) has concluded that “intimate kissing” that lasts at least 10 seconds can transfer 80,000,000 bacteria between the participants’ mouths. So many microbes sloshing around – it’s a little bit gross, a little bit cool, and 100% science.
NPR wrote a short piece about it here.
A recent publication (B. Misof, et al. 2014. Phylogenomics resolves the timing and pattern of insect evolution. Science 346 (6210): 763-767.) takes on the herculean task of finding when insects first evolved. This is a particularly vexing question because 1) insects are squishy and don’t fossilize well, and 2) the vast majority of the species on the planet are insects. This is an insect world, we just live in it.
The paper was summarized BRILLIANTLY on WIRED (here). Including my favorite quote:
“Making sense of the diversity of insects in collections has traditionally been a task for a lone expert, usually specializing in just one subset of a group. They become so identified with their study organisms, they may be introduced as “The Ant Man” or “The Wasp Woman.” (No taxonomists I know wear spandex tights and capes to work, for which I am profoundly grateful.)”
Find out about when insects evolved, when they diversified (surprisingly, it started PRIOR to the radiation of angiosperms) and more.
Have you thought that not all the genes in your body might have the same evolutionary interests? The mouse Y chromosome has just been revealed after years of superhuman slog and turns out to be strikingly different from other non-recombining sex chromosomes in two main ways. Firstly, the mouse Y contains almost no DNA signatures of its past as a non sex chromosome. Secondly, most of it isn’t “junk”. Both these observations have shown just how much conflict within a genome can shape the evolution of entire chromosomes.
Figure from Sho et a. 2014, showing how much of the mouse Y contains recently evolved, repetitive coding sequences.
In a recent keynote address at the High Throughput Sequencing for Neuroscience meetings, Sean Eddy from the Howard Hughes Medical Institute addresses the need for biologist to do their own sequence analysis. Although this talk was given by a neuroscience rather than an evolutionary biologist, the conversation is generally applicable to the entire biological community.
“But if you’re a biologist pursuing a hypothesis-driven biological problem, and you’re using using a sequencing-based assay to ask part of your question, generically expecting a bioinformatician in your sequencing core to analyze your data is like handing all your gels over to some guy in the basement who uses a ruler and a lightbox really well.”
“If you learned to implement it in Perl — and you could do this in an afternoon, with a few lines of Perl code — I think you would find yourself endowed with a superpower, like Wonder Woman with her golden lasso of truth, and it’s a superpower that a biologist can use with surprising effectiveness on large data sets.”
Find the whole article here.
Figure 1 from Grice and Segre (2011), showing the distribution of viruses, bacteria, fungi and mites on our skin and where glands and hair follicles originate.
Our skin is an amazing organ – it keeps our guts in and intruders out. We have an average of 1.8 m2 and this area contains many distinct regions that vary in pH, temperature, moisture, exposure, etc. Your forearm is dry, your cheeks are oily and your elbow crease is considered “moist”. Hair follicles, pores, glands, nails – if we think of our bodies as planets, there are a lot of different habitats. And it turns out our habitats are home to many, many things.
Oh et al. (2014) analyzed 263 samples from 15 human beings at 18 habitats (anatomical skin sites). They were interested in the biogeography of skin – and how it varies between people and across habitats. Do all forearms look alike? Do all “dry” habitats have similar function? It was already known that there are large scale microbial diversity patterns in the skin microbiome. For example, oily sites contain relatively low taxonomic diversity, perhaps because these sites are most selective when it comes to who is able to live there. At the other end of the diversity spectrum are dry sites, which tend to have high diversity.
The winner of this year’s “Dance Your Ph.D.” contest, Uma Nagendra, studies fungi that infect the roots of pine seedlings—seedlings that grow too close to an adult tree, such as their own parent, can be at higher risk of fungal disease transmitted from the adult’s roots. Nagendra depicts those underground interactions, and what happens when a tornado upends them, in a choreographed trapeze performance. Cool!
Monarch butterflies (Danaus plexippus) are among the most widely recognized wild creatures in North America. Their distinctive orange-and-black wings, which warn predators that the butterflies are chock full of toxins from the milkweed they eat, make them easily spotted in backyard flower beds. They’re also known for a massive annual migration, flying thousands of miles between wintering colonies in central Mexico and summer sites across the United States and Canada. More recently, it’s been discovered that female monarchs infected by parasites respond by laying their eggs on food plants that can prevent the parasite from infecting their offspring.
Monarchs are also one of the more visible victims of the massive changes humans have made to the world around us. Increased conversion of farmland to corn production has reduced the supply of milkweed, the butterflies’ only food plant, across much of the Midwest. It’s gotten so bad the number of monarchs making the annual migration back to Mexico hit a record low last year, and while things were better in 2014, a nationwide campaign to encourage planting of milkweed in home gardens is only beginning.
For all our familiarity with monarchs, we’ve known remarkably little about their evolutionary history. That’s changing rapidly now, as evidenced by a paper published last month in the journal Nature, which uses a big new genetic dataset to trace the origins of some of the monarch’s most distinctive features.