The domain of evolutionary biology is staggering – the field’s core mission is nothing less than to understand the history and forces that have shaped the diversity of life on Earth.
Professor Scott V Edwards, Past President of the Society for the Study of Evolution, highlights the rise in influence of evolutionary biology in a wide range of critical spheres…
Professor Scott V Edwards
Evolutionary biology is a diverse field with increasing relevance for human society in areas such as medicine, agriculture and the response of organisms to climate change. As President of the Society for the Study of Evolution in 2012, I have a unique perspective on the changing face of evolutionary biology and its contributions to society. Not only is the discipline being transformed by modern technology, particularly in the areas of genomics and computational biology, but scientists working in many different disciplines – from physics to drug discovery and biomedicine – are realising the relevance of evolutionary biology to their respective fields. Vast digital databases, such as the Global Biodiversity Information Facility (GBIF) and the Encyclopaedia of Life (EoL), provide unprecedented access to and integration of the world’s museum specimens and biodiversity literature, key resources in these times of rapid climate change.1-2
The domain of evolutionary biology is staggering – the field’s core mission is nothing less than to understand the history and forces that have shaped the diversity of life on Earth. As a result, evolutionary biologists employ many different tools in their research. Some collect their data primarily in the field, scouring the globe for new, as yet undescribed species. Others work full-time at the computer terminal, often mining vast repositories of data. The vast majority of evolutionary biologists still use the remarkably prescient framework for mechanisms of evolutionary change via natural selection as outlined by Charles Darwin in the 19th
Century. A key tool in this paradigm is the comparative method – comparing traits, whether genetic, physiological or ecological, between species or individuals of the same species. But Darwin would have marvelled at the precision with which we can observe and dissect the evolutionary process in the genome and in nature and the detailed mathematical theory that now guides our hypotheses and predictions.
The evolutionary biology of humans and their diseases conveys some of the directions in which the field in general is growing. The recent completion of genomes of a Neanderthal and a poorly known human relative called a Denisovan (the latter genome produced from a tiny fragment of finger bone discovered in Siberia) has provided stunning detail on the diversification of the human family over the past one million years and suggests that remnants of the Neanderthal’s genetic makeup may persist today in some human groups, such as Europeans and Asians.3-4
Just last year, a large consortium of scientists published the first instalment of a massive collaborative effort called the Encyclopaedia of DNA Elements (ENCODE) project, with the goal of understanding how each of the three billion letters in the human genome works.5
Although the first draft of the human genome was presented in 2001, scientists still lack a clear view of genome function and how it relates to disease, especially since the genes encoding proteins – the building blocks of life and catalysts for biochemical reactions – comprise only one per cent of our genome. Using a diverse set of biochemical assays that help define the functions of regions outside of genes, the ENCODE consortium found that a full 80 per cent of the human genome is, at least in some tissue types, transcribed into RNA, a molecule that serves as the intermediate between DNA and protein and also has many diverse regulatory functions.
However, by a different measure – one informed by evolutionary biology – the human genome shows much less evidence of widespread function. By comparing the genomes of different species, such as humans and other mammals for which there are also fully sequenced genomes, scientists have found that only about 90-100 million (3-5 per cent) of the three billion base pairs in the human genome actually change slowly enough to suggest a strongly conserved function over evolutionary time. Some parts of the genome, such as genes of the immune system, must change rapidly to keep up with the similarly rapid change of the pathogens that constantly bombard us, and these genes would be undetected by these approaches. Still, the discrepancy between biochemical and evolutionary estimates of genome function is substantial, revealing just how challenging it is to decode and interpret the functional properties of the human genome. With an evolutionary perspective, it’s clear that scientists must embrace a definition of genome function that allows for temporal changes in the operation and movement of parts of the genome between functional and non-functional states over time. Such a feature is now being incorporated into the latest models of genome evolution.6
Evolutionary biology has had a similarly strong impact on the study of pathogens over the past several decades, and departments of microbiology, epidemiology and schools of public health worldwide are now populated by scientists with diverse types of evolutionary training. Evolutionary biology forms a core approach in the sleuthing that accompanies the control of many recent disease outbreaks, including the 2009 H1N1 swine flu outbreak in Mexico and the United States.7
Using a combination of genomics and statistics, scientists found that swine flu was produced by a recombination of segments from several ancestral viruses found in birds, pigs and humans, and had likely been circulating in pigs several years before it jumped to humans. These insights reveal the diverse ways in which evolutionary biology can contribute to human health as well as to pressing societal issues such as sustaining biodiversity and climate change.
Green et al. 2012, A draft sequence of the Neanderthal genome. Science 328: pp. 710-722
Meyer et al. 2012, A High-Coverage Genome Sequence from an Archaic Denisovan Individual. Science 338: pp. 222-226
The ENCODE Project Consortium. 2012. An integrated DNA Encyclopedia of DNA elements in the human genome. Nature 489: pp. 57-74
Ponting, C P, C Nellaker, and S Meader 2011, Rapid Turnover of Functional Sequence in Human and Other Genomes. Annual Review of Genomics and Human Genetics, Vol 12 12: 275-299
Smith et al. 2009, Origins and evolutionary genomics of the 2009 swine-origin H1N1 influenza A epidemic: 459: pp. 1,122-1,125
Professor Scott V Edwards
Society for the Study of Evolution
[This article was originally published on 20th
March 2013 as part of Science Omega Review UK