In 1799 George Shaw, the head of the Natural History Museum in London, received a bizarre pelt from a Captain in Australia: a duck bill attached to what felt like mole skin. Shaw examined the specimen and wrote up a description of it in a scientific journal, but he couldn’t help confessing that it was “impossible not to entertain some doubts as to the genuine nature of the animal, and to surmise that there might have been practised some arts of deception in its structure.” Hoaxes were rife at the time, with Chinese traders stitching together parts of different animals – part bird, part mammal – to make artful concoctions that would trick European visitors. Georgian London was becoming rather skeptical of these increasingly fantastical pieces of taxidermy.
Ever since the discovery of DNA as the molecule responsible for genetics, in particular when it became clear that the ordering of the chemical components in this polymer was the information that DNA stored, scientists have dreamt about determining the full sequence of the human genome. For Francis Crick, who co-discovered the structure of DNA (along with James Watson, using data from Rosalind Franklin) this would be the final step towards unifying life and chemistry: demystifying the remarkable process that leads to us and all other living creatures. Back in 1953 this was a fantasy, but slowly and steadily over the ensuing decades it became a reality.
After human, the most studied animal, by a long margin, is mouse. Or, more strictly, the laboratory mouse, which is a rather curious creation of the last 200 years of breeding and science.
Laboratory mice originate mainly from circus mice and pet “fancy” mice kept by wealthy American and European ladies in the 18th century. Many of these mice had their roots in Japan and China, where their ancestors would have been kept by rich households. Unsurprisingly, the selection of which mice to breed over the centuries came down to habituation to humans and coat colour rather than scientific principles.
My ninth genome of Christmas is a bit of an indulgence: the gentlemanly, diminutive Medaka fish, or Japanese rice paddy fish.
When Mendel’s laws were rediscovered in the 1900s, many scientists turned to local species they could keep easily to explore this brave, new world of genetics. In America, Thomas Hunt chose the fruit fly. Scientists in Germany explored the guppy and Ginuea pigs. In England, crop plants were the focus of early genetics. In Japan, researchers turned to the tiny Medaka fish, a common addition to many of the ornamental ponds maintained in Japanese gardens.
You might think that the best chemists on earth are humans, living perhaps in Cambridge, Heidelberg, Paris, Tokyo or Shenzhen, beavering away in laboratories filled with glassware, extraction hoods and other human-made things. But then you would be discounting a multitude of bacteria that have cracked all sorts of chemistry problems over the course of their long evolution, and that still harbour secrets about how they manipulate molecules. One inventive clade of bacteria, the cyanobacteria, quite literally changed the world, and built the foundations of modern life.
When you first think of domesticated organisms, dogs might come to mind (our earliest domestication), or perhaps wheat, or cattle or rice. But you might easily overlook single-celled yeast: the key active agreement in both bread and alcohol, and a great enabler of the agricultural revolution in Europe.
If humans have an arch enemy, it might well be the tiny, blood-borne parasite Plasmodium falciparum. This nasty beast causes most of the malaria in sub-Saharan Africa and, together with its cousins, in many tropical zones throughout the world. It kills huge numbers of children every year, and constantly cycles through the bloodstreams of its many survivors. It has been with us since our explosive migration out of east Africa, and in fact many genetic diseases (including sickle-cell aneamia and thalassemias) are tolerated by human populations because they confer an advantage against this nasty parasite.
The humble fruit fly – Drosophila melanogaster, to be specific – has played a central role in the history of genetics and molecular biology and continues to be important in research.
Championed by the legendary Thomas Morgan at the start of the 20th Century, Drosophila provided a practical foundation for genetics – long before the discovery of DNA as vehicle for passing down heritable information through generations. Morgan and colleagues developed the concepts of ‘gene’ and ‘linkage’, and so we have ‘Morgans’ (and more commonly, centi-Morgans, cM) as the basic units of genetic maps.
The first technological innovation to radically change human society was agriculture. The ability to cultivate – rather than hunt or pick – food had a profound change on everything from our immune system to our societal structures. It encouraged specialisation, favoured robust, complex inter-generational knowledge transmission and enabled the explosive growth of this bipedal ape.
In the early 90s Svante Paabo, a charismatic, energetic innovator, made a bold proposal: that to study human origins one would do well to sequence the DNA of ancient hominids, in particular those species which had gone extinct. After all, DNA could be detected in their bones, provided they were not too old and kept dry and cold.