This is actually a picture of a fish embryo, but do you notice anything different than what you would expect? I do, it doesn’t have fins, it has legs. The New Scientist says ‘Fossils show that limbs evolved from fins’, but a new study shows how it happened in the lab. Yes, in the lab.
A scientist, Fernando Casares, and his collegues injected this zebrafish with the gene hoxd13, which is from a mouse. This gene controls the development of ‘autopods’, a precursor to hands, feet and paws.
In fact, Zebrafish naturally carry hoxd13, but they don’t produce as much of the protein as tetrapods (all four-limbed vertebrates and birds). Fernando and his fellow scientists were hoping that if they injected the extra copies of this gene into the zebrafish embryo, some of their cells would also make more of the protein.
As you can see, they succeeded. By 24 hours later, all the embryos were developing autopods instead of fins. However, they grew for four days, but then sadly died.
But, I think this an amazing step forward for science, as we can now picture the evolution process in our own laboratories. Fantastic.