In West Africa, the African oil palm has been cultivated for centuries. The plant was considered to be very useful, since it’s red oil-rich fruits can be used in a variety of products including soap, candle wax and engine lubricant. In the late 1840s, it played a key role in the British Industrial Revolution, and when it was discovered that the (west) African oil palm grew rather well in the hot, damp climates of the Far East, plantations began to spring up in Malaysia and Thailand. Palm oil is an extremely versatile vegetable oil; it is highly fractionable, meaning that it can be separated into many different products. On top of this, the oil palm is an extremely productive plant, producing 3.6 tonnes of palm oil per hectare; up to ten times more than other oil-producing crops such as rapeseed, sunflower or soyabean. Palm oil seemed to be an excellent choice of oil. Demand grew, and plantations spread into Malaysia and Indonesia in the 1930s. The oil palm is now grown on almost every continent on Earth, although the vast majority is still found in Southeast Asia.
At this time of year, as the nights begin to draw in, and a chill appears in the air, the idea of simply curling up in a warm spot and sleeping through the winter months is very tempting. Unfortunately for us, Humans are not among the species which undergo hibernation. However, many other mammals reduce their activity levels during the winter, and a few undergo full hibernation, biochemically altering their metabolism to wait for more favourable conditions.
Believe it or not, out there somewhere, in a brightly lit laboratory, is a person in a lab coat, folding DNA, proteins and other biological compounds to provide innovative new medicines, tackle microengineering problems and create intriguing art. Welcome to the world of nantechnology.
The structure of DNA
Nanotechnology is the study of materials and devices smaller than 100 nanometers (10-5 or 0.000001 cm), and it is being applied to a diverse set of problems including drug delivery, nanorobotics, gene therapy, microelectronics and molecular computing. DNA nanotechnology involves the construction of self-assembling minute artificial structures from nucleic acids (the building blocks of DNA). DNA can be used to form a functional nanostructure itself, or it can be used as a scaffold to direct the assembly of other molecules (e.g. carbon, protein, peptides) into a functional structure. This is possible because of the strict base pairing rules of DNA, which means that strands will only bind together if they share complementary sequences. Base sequences can be therefore designed that will form specific structures. This is a major advantage over other materials used in nanotechnology such as proteins and nanoparticles. Dynamic DNA nanostructures can also be designed that react to certain chemical or physical stimuli, and DNA engineering is allowing scientists to design sequences that catalyse reactions, influence gene expression and modify the properties of natural DNA. Even more amazingly, DNA ‘printers’ have now been developed which can produce DNA strands with specific sequences, and bind them to a surface.
Is Anybody Out there?
The universe is vast and ancient, containing billions of stars. The likelihood is that other Earth-like planets, suitable for intelligent life, exist out there. Given the vast amount of time available, some of these suitable planets should have evolved intelligent life, some of these lifeforms should have developed interstellar travel, which should in turn have enabled them to colonise the galaxy within just a few tens of millions of years. So, we should expect the universe to be teeming with intelligent life. Any yet, we find none. Despite 50 years of searching, we have not yet found any evidence of extraterrestrial civilisations. We have failed to detect artificial signals in space, and we have failed to find any artefacts of intelligent life. This is the basic tenant of the Fermi paradox; we expect intelligent life to be prevalent in the galaxy, and yet we are unable to find it.
Modern medicine can boast a number of triumphs against infectious disease over the past century; Smallpox killed around 500 million people in the 20th Century before its eradication in 1979 as a result of vaccination. The Global Polio Eradication Initiative began in 1988 and has achieved considerable success, with eradication complete in the Americas, Europe, the Indo-West Pacific and China. Last year, only 223 cases of Polio were reported globally. It comes as no surprise that those diseases against which we have had the greatest success are those that affect developed nations. Increasing attention is now being paid to the many debilitating and often deadly infectious diseases, which continue to affect billions of people in developing nations; a category of diseases known as NTDS (neglected tropical diseases).
In the 60 years since Watson and Crick’s landmark discovery of the structure of DNA, our understanding of how genes influence disease has increased exponentially. For some conditions, an exciting therapeutic prospect exists: gene therapy. Gene therapy attempts to repair faulty genes instead of simply treating symptoms.
For many conditions, the exact genetic mechanisms underlying them have now been elucidated. While a lot of diseases are the result of a complex interaction between multiple genes and environmental factors, others are the result of a single mutation, resulting in the failure to produce an essential functional protein. For such conditions, an exciting therapeutic prospect exists: gene therapy. In principle, the idea behind gene therapy is very simple. Whereas conventional medicine generally attempts to replace the missing gene product or repair the damage caused by its absence, gene therapy attempts to repair the faulty gene itself. Why treat symptoms when you can treat the cause?
The field of research into personality and behavioural syndromes in animals has blossomed over the past few decades. With ample evidence for it’s existence, biologists have begun to consider its evolution; what is the adaptive benefit of personality? How are multiple personality types maintained in a population? Why do personalities exist when they sometimes result in maladaptive responses?
All these questions, and any evolutionary questions we might care to ask, make the assumption that personality is heritable. Without heritability, personality cannot be passed from generation to generation, and cannot be subject to natural selection. There is now plenty of evidence for high heritability of many personality traits in animals, although there is also an important influence of the environment too. Heritabilities estimates vary, from 0.22 – 0.61 in wild great tits, 0.32 in social spiders, 0.54 – 0.66 in humans and 0.2 – 0.8 in dumpling squid. These genetic influences may in part be reflected in brain morphology; one study in humans found differences in brain structure relating to neuroticism, conscientiousness, and extraversion. More neurotic people have a smaller total brain volume and a smaller frontotemporal surface area, whilst extraverts have a thinner inferior frontal gyrus.
To even the most casual observer, it is clear that people are not homogenous in their behaviour, and that this goes beyond possible nurture influences such as cultural upbringing. Individuals vary in their behaviour in a consistent manner; some people are generally more aggressive, friendly and adventurous in every aspect of their lives. So obvious is this observation that we even have a word for it – personality. Likewise, anyone who has spent any significant amount of time in the company of animals will almost certainly acknowledge that they are not all the same. The extent to which this is apparent varies from species to species, of course, but the observation is not a revolutionary one. And yet, until relatively recently the concept of ‘personality’ in non-human animals was revolutionary. And it has had to work hard to shake off the criticism of anthropomorphism and pseudoscience.
It was long assumed that animals were infinitely plastic in their behaviour, being able to respond adaptively to all environments. When people actually started to look, however, it became apparent that this wasn’t the case. Individuals showed substantial variation in their responses to certain events and environments, and these responses were not always adaptive. There was a strong correlation however, in the responses of a single individual over time. Personality, you say?
Over the last few months I’ve been discussing the characteristics that make us human, and which of the classic ‘uniquely human’ traits, really are ours and ours alone. But one aspect of human behaviour which I have not discussed so far is our use of fire. No other animal has learned to harness and control fire as humans have.
A recent discovery of wood ash along with animal bones and stone tools in a cave in South Africa suggests that humans may have used fire as early as 1 million years ago. This is around 300,000 years earlier than previously thought, and may indicate that earlier hominid species such as Homo erectus were using fire. Other tentative support for fire use by early hominids such as H.erectus and A.robustus have been found in South Africa and Kenya, possibly as early as 1.5 million years ago. Further evidence from Northern Israel in the form of burnt flint tools and plant remains indicates that H. erectusmay have been controlling fire around 800,000 years ago.
When you design many objects that perform similar tasks, the logical strategy is to reuse the same design, perhaps with small modifications, for each object. There would be little point in coming up with a new design every time, right!? In nature, however, there are many species that do similar things but have arrived at their method through different designs. This is known as convergent evolution.
Intelligent design, and decent by modification, predict different patterns of similarities and differences between species. Evolutionary theory, which places all living things on a tree of relatedness, leads us to expect that species that are more closely related to each other should tend to be more similar. This is because they have both evolved from a recent ancestor. This ancestor has been ‘modified’ in various ways by natural selection to produce the two (or more) daughter species, but with a shared starting point for these modifications, we expect a fairly similar outcome. Traits that are shared between species due to shared ancestry are known as homologies. Homology has been the basis for determining relatedness between species (phylogeny) for hundreds of years. However, as early taxonomists noted, there are some occasions when species share traits despite the lack of a recent common ancestor. Often these species have reached a similar solution to a shared problem, despite being only very distantly related. This is known as convergence, and the more we look for it in nature, the more we find.