Foreign pieces of DNA are found in the genomes of many animals – these ‘Genomic parasites‘ are pure, genome hopping pieces of DNA code which embed their lifecycle within the DNA in our own cells. You could call this genomic parasitisation a form of genetic modification, just as scientists in labs the world over use simple molecular biology techniques to insert useful genes into genomes to better understand biological processes. However, most of the time, genomic parasites like transposons have no function in their hosts and simply hitch along for the ride, reproducing as the host reproduces. This doesn’t fit our usual understanding of the meaning of genetic modification, which involves humans and active manipulation of the genome, in most cases to improve it.
Would you look at that! The story of mosquitos, cheese and body odour has taken another leap into scientific respectability with a paper being published in the pinnacle of journals, Nature. “Evolution of mosquito preference for humans linked to an odorant receptor” by McBride and colleagues was published towards the end of last year and looks at how the domestic form of the mosquito Aedes aegypti has evolved striking evolutionary adaptations that help it to find, bite, and spread disease to humans.
When I talk about my career and my interest in evolutionary biology, I often get asked, “How do you actually get new species?”. It’s not a stupid question; for people without a background in biology it really is very hard to imagine how the diversity of life we see today has formed from the types of ancient creatures we find in the fossil record. I normally look to my favourite fish, the Mexican blind cavefish, or point out the variety that can be produced in the single species of dog, or mention horizontal gene transfer to confer antibacterial resistance in bacteria, to show how even small changes can result in quite big differences in a species. Add to that vast amounts of time and it becomes a little easier to imagine the “hedge” of life taking shape.
I love papers like this. The extreme level of detail people go to in the quest to discover is fascinating. The question that always comes to my mind is “What made them decide to research this in the first place?” Was it through trying to understand more about where humans come from or was it purely a mathematical and physical curiosity about how we walk? The beauty of science is that it is allowed to be curiosity driven – just like those papers and pieces of research which made it into the IgNobel Awards and have ended up being pivotal in their respective fields.
“Impulsive ankle push-off powers leg swing in human walking” is a rather complicated paper, full of mathematical terminology and notation, but if you can get through the equations you’ll discover a story that shows how human walking has been fine-tuned, linking this physical paper to fundamental questions of human origins. Continue reading “The physics of human walking and considering the wider picture”