Why your pup looks at you (it’s not just to beg for a treat)

French bulldogLast Christmas, as I was patting my sister’s little female French bulldog, I found myself thinking how relaxing it felt – well, apart from the slightly itchy eyes. At some point, the dog tilted her head towards me, and we embarked on some sort of staring contest. As the mutual gaze prolonged, I started wondering: What could be going through her mind? Was she thinking about something? Why was she keeping her big but oh-so-cute bulgy eyes fixed on mine?

The interactions between humans and dogs are rather particular, with a level of social bonding and emotional engagement unusual for members of two different species. When compared with wolves, dogs’ closest relatives, and great apes, humans’ closest relatives, dogs appear much more skilled at recognizing and using social cues such as gesture or gaze direction to cooperatively interact with humans, even already as puppies.

But it’s not just that. Why is it that we feel genuinely attached to dogs? What are the biological mechanisms underlying the friendship and love we come to develop towards them? Continue reading

Adapting to arsenic

The dose makes the poison. However, that dose may not be the same for everyone. A recent study shows that a human population of the Argentinean Andes has genetically adapted to a polluted environment and increased its resistance to arsenic toxicity.

Natural selection is one of the mechanisms driving evolution and is central to the notion of adaptation: individuals that possess characteristics beneficial to their survival and reproduction in a given environment are likely to produce more offspring than other individuals; as they pass on the beneficial traits to their descendants, these characteristics become more and more common in the population. Continue reading

Lactase persistence and natural selection

Here is an interesting post on John Hawks’s blog: Selection and lactase persistence.

After reading an article by John Hawks in Scientific American (No, Humans Have Not Stopped Evolving), a reader reached out to him, asking for clarification about a point that left him puzzled: why would a genetic mutation that allows lactase persistence after weaning age (meaning the lactase enzyme keeps being produced in adults so that they can still efficiently digest the lactose in milk) stick around in a population when it (apparently) does not confer a direct advantage in survival/reproduction? Continue reading

Around the time of early Homo

Beginning of summer, now is as good a time as any to clear some space on my desktop and finally get rid of all the Firefox tabs I keep open, firmly believing I will have time to read them, soon. I’ve decided to try and go through the scientific articles that I have accumulated in the past months, and I will probably write about a few of them along the way.

Among the first ones on the top of the pile is a review published in Science on July 4th (not that long ago; I will slowly walk my way back in time). The paper, by Antón and colleagues, is a scientific review about the evolution of early Homo. As any review, it goes over the scientific literature available on the topic, taking into account existing data, previous hypotheses and interpretations, and recent advances, and weaves it into an account of what is currently known and unknown.

Paleoanthropology is certainly not my area of expertise, but once in a while I like to read a paper on the subject and learn a little something new. So, what have I (re)learned here? Continue reading

In brief (June 2014) – Aspirin and influenza, evolution of self-control, celecoxib and cancer

Three picks among what I’ve read in the past months:
aspirin, prostaglandin E2, and influenza, or how blocking the production of prostaglandin E2 can help in the fight against influenza A virus
evolution of self-control, or how absolute, not relative, brain size correlates with cognition across species
drug repurposing, or how celecoxib, a non steroidal anti-inflammatory agent used in arthritis, may help to inhibit the formation of new blood vessels, tumor growth, and metastasis in mice. Continue reading

Origins of the genus Homo, BU “Dialogue” series

Staying on the topic of human evolution, I can recommend the following discussion, recorded a couple of years ago as part of the “Dialogue” series organized by the Department of Anthropology at Boston University:
The Mysterious Origins of the Genus Homo (Boston University, Dialogues in Biological Anthropology).

The past 4 million years can be divided into two broad chunks when thinking about the story of human evolution: Continue reading

The new Dmanisi skull

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Georgian National Museum

The skull of an early Homo individual, discovered in Georgia in 2005 and presented on October 18 in the scientific journal Science, is truly a wonderful find. Not only was it recovered relatively intact and complete, but together with four other cranial fossils found at the same site, it constitutes a unique window into how much early Homo individuals could vary from one another. Continue reading

In brief (August 2013, part II) – microbiome and speciation, and more viruses

Picks for this month, second part:
gut bacteria keeping species apart, or how the microbiota may promote speciation by contributing to offspring lethality when two species are interbred,
new genera of ocean-dwelling phages, or how analysis of an aquatic bacterium led to the discovery of twelve new genera of bacteria-infecting viruses. Continue reading

Book review: Paleofantasy, by Marlene Zuk

A few weeks ago I read Paleofantasy: What Evolution Really Tells us About Sex, Diet, and How We Live, by Marlene Zuk, a professor of ecology, evolution and behavior at the University of Minnesota, USA. I was drawn to the book after reading a review about it in Science, and I was not disappointed. The book makes for an entertaining and easy read, taking us through what is known about human evolution and how scientists investigate the matter, while debunking some common popular ideas about our evolutionary history and how we should “behave” according to it. Continue reading

Antibiotic resistance, Higgs boson, likes on social networks and four-winged birds

A few samples from this week’s science news:

– This week’s issue of the scientific journal Nature focuses its editorial on the threat posed by the rise of antibiotic-resistant bacteria and on the importance of that threat being given proper attention by policy-makers worldwide.

Over the last decades, misuse and overprescription of antibiotics have led to an increase in antibiotic-resistant bacteria and related infections. Despite a growing number of voices warning against the dangerous consequences of such practices, antibiotics remain largely over-prescribed by doctors and are still widely used as a growth supplement in livestock. The general decline in research and development of new classes of antibiotics is making the situation even more alarming. While Nature’s editorial show that policy-makers Continue reading