biology, evolution, Science, science news

Human evolution continues to get more complicated

A good, if slightly technical article in the Guardian today here, about the ever-contentious split between modern humans (Homo sapiens) and Neanderthals. The evidence for interbreeding between humans and Neanderthals added up quite convincingly after the initial surprise discovery, probably shortly after the “Out of Africa” migration around 75,000 years ago. This article reports on results from sequencing mitochondrial DNA, which is only transmitted through the female line, suggesting there was some interbreeding between 413,000-270,000 years ago, a staggeringly long time ago. This is way before the main migration out of Africa by modern humans, and not that long after the split between the Neanderthal and Homo sapiens lineages from their common ancestor around 500,000 years ago. It seems that there may have been smaller migrations before our species successfully established itself outside of Africa.

I’ve written about human evolution before here, which gives an overview of some of the more recent findings about our relationships with other hominids. This new finding really strikes me again how migration is a defining feature of our species; it may well have been so for other hominids too. Maybe this is why our ancient relationships are just as mixed up as our modern ones.

biology, genetic modification, News, Science

Writing movies into DNA

Well, what will they think of next? A little while ago, I wrote about the possibilities of using DNA as information storage. Researchers have now managed to insert a little movie into the genome of the E.coli bacterium (the workhorse of the genetics world). They used the CRISPR/Cas9 genome editing technique to insert the five frames of a galloping horse. Essentially, the snippets of DNA generated by CRISPR were used to correspond to pixels. Here’s the GIF:

galloping horse

Of course, you need to decode the message written in the nucleotides of the bacterial DNA to reconstruct the image (or movie), so you also have to have the ability to read it and know the code, and it’s incredibly laborious. You can’t just read it off one cell either, nor with one pass – it took several hundred thousand reads for the whole thing.

So why would you bother? Honestly, that’s a little ambiguous at the moment. Their original idea was to actually create a recording system to monitor changes happening in cells, in order, ultimately, to decipher how brain cells take on distinct identities. Instead of using indirect measurements or experimental perturbation to answer these questions, it would essentially get the cells to tell you what was happening to them themselves. They didn’t achieve that, but it’s a step towards it. Like many science advances, it’s an impressive technical feat that for now remains just a curio, but who knows where it may ultimately lead?

 

Reference

Shipman, S. L., et al.  Nature (2017). http://dx.doi.org/10.1038/nature23017

biology, Developmental biology, Explainer, Opinion piece, Science, Science and society, SF and science

Will we ever have artificial wombs?

A few years back I attended the annual conference of the British Society for Developmental Biology. There was a discussion session towards the end of the day concerning future developments and directions in our field of research, namely how one goes from the early embryo to, ultimately, the adult human (or other organism). Into a lull in the conversation, my then-boss, who was heavily pregnant with twins and very uncomfortable, interjected the following question: “I only want to know one thing right now: when are we going to be able to grow babies in artificial wombs?” Good question…

Continue reading

evolution, Miscellaneous, Science and society

Humans: born to…migrate?

Following on from that Nature feature on human migration I blogged about  a couple of weeks ago, is another interesting piece in Science provocatively titled: “Busting myths of origin.” It is, however, exactly as the title says: analysis of DNA and isotopes in bones and teeth is showing that most of the people of the world are the products of multiple migrations: there are no “pure” peoples of any kind, with the exception of a very few groups, notably the indigenous Australian Aborigines, who, largely through accidents of geography and circumstance, remained isolated from many other human groups for a relatively long time. Migration and mingling, it turns out, is the norm for our species.

Continue reading

biology, evolution, Science

The eyes have it

There’s been a lot of study into how vertebrates colonised the land, conjuring up lovely visions of our fishy ancestors hauling themselves out onto the mud on stumpy proto-limbs, helped by exciting fossil finds like Tiktaalik. What hasn’t been studied so much is why. It seems obvious – whole new ecological niches to expand into, and a rich abundance of invertebrate life to eat…but how did the animals know this before they got there? Well it may have been because they had evolved eyes sophisticated enough to take a good look at the view… Continue reading

politics

Perception versus reality: the refugee crisis

There’s been an awful lot of talk thrown around lately about fake news, people living in “Facebook bubbles” where they only get news that agrees with opinions they already have, etc. There is also a lot of ongoing serious analysis about how people’s perceptions differ from reality, and how easy this is to influence in subtle and not-so-subtle ways. These things affect how people vote, and the policies of their governments – but these too, can be based on false perception. So I thought I’d just link to a piece in Nature [free to read] about the refugee situation worldwide; it has a lovely clear infographic you can download and good interactive figures. This is based on as good a data as is available, and it made me realise a lot of my own perceptions were flawed. I knew already, for example, that the of numbers of refugees entering Europe from Syria was much higher than it actually was, and that most of these refugees were being absorbed by neighbouring countries like Lebanon and Turkey. I did not know this:

Refugees 1