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Africa – the continent of mountain archipelagos

25 May 2020 | Story Dr Ralph Clark | Photo Charl Devenish

Afromontane_read more — Afromontane research area in the Eastern Free State.

Africa could be called ‘the continent of mountain archipelagos’ for the unusual fact that most of Africa's mountains are isolated ‘islands’ rather than linear, continuous mountain systems such as those in Asia (e.g. the Himalayas), Europe (e.g. the Alps), and the Americas (e.g. Rockies and Andes). Even in Southern Africa, where we have the linear Great Escarpment (5 000 km long), this system is so old that it has been breached in innumerable places by erosion into a series of independent mountain blocks.

The result of this mountain disconnection is that Africa's mountains display biodiversity patterns more akin to islands than to mountains: rich, exciting, and unique, and full of very localised and interesting species. Likewise, mountain communities have established and evolved unique cultural ways of life and traditions in their particular mountains – isolated from other groups on other mountains. But in some mountains, internecine warfare and tribal conflict caused mountains to become boundaries rather than welcoming places. This was certainly the case during the Mfecane in Southern Africa, ultimately leading to the birth of Lesotho as the ‘Mountain Kingdom’. Colonialism took this to a new level, and – for most of Africa – mountains became international borders between empires, splitting ethnic groups into several nationalities and marginalising large segments of the population in these new countries. This same geopolitical situation continues today, with major implications for the sustainable management of mountain ecosystem services, natural capital, and socio-cultural sustainability in multinational contexts.

The Afromontane Research Unit (ARU) – a continental leader in African mountain research – seeks to explore these socio-ecological complexities in terms of sustainable development, providing research that can help to secure a positive future for the people, biodiversity, and goods and services provided by Africa's mountains. As part of its mission, the ARU is leading the way in encouraging a multidisciplinary community of practice that will drive a science-policy-action interface for Southern African mountains in decades to come. As virtually all of Africa's water comes from its mountains, this is a critical service to a region increasingly at risk from drought and the socio-political implications of rivers and taps running dry.

Although the Qwaqwa Campus is the home of the ARU, the ARU is welcoming affiliations from across the UFS and beyond. Should you wish to become affiliated to the ARU, please contact the Director, Dr Ralph Clark at ClarkVR@ufs.ac.za. Visit the new ARU's website

News Archive

UFS study on cell development in top international science journal

2008-09-16

A study from the University of the Free State (UFS) on how the change in the packaging of DNA with cell development influenced the expression of genes, will be published in this week’s early edition of the prestigious international, peer-reviewed science journal, the Proceeding of the National Academy of Sciences of the USA (PNAS).

The PNAS journal has an impact factor of 10, which means that studies published in the journal are, on average, referred to by ten other scientific studies in a two year period. The South African Journal of Science, by comparison, has an impact factor of 0.7.

The UFS study, funded by the Wellcome Trust and the National Research Foundation (NRF), looked at how the change in the packaging of DNA with cell development influenced the expression of genes. It is very relevant to research on stem cells, an area of medicine that studies the possible use of undifferentiated cells to replace damaged tissue.

Prof. Hugh Patterton, of the Department of Microbial, Biochemical and Food Biotechnology at the UFS, who led the study, said: "We are extremely proud of this study. It was conceived in South Africa, it was performed in South Africa, the data were analysed in South Africa, and it was published from South Africa."

When a gene is expressed, the information encoded in the gene is used to manufacture a specific protein. In eukaryotes, which include humans, there is approximately 1m of DNA, containing the genes, in every cell. This length of DNA has to fit into a cell nucleus with a diameter of only about 10 micrometer. In order to fit the DNA into such a small volume, eukaryotic cells wrap their DNA onto successive protein balls, termed nucleosomes. Strings of nucleosomes, resembling a bead of pearls, is folded into a helix to form a chromatin fiber. The study from the UFS investigated how the binding of a specific protein, termed a linker histone, that binds to the length of DNA between nucleosomes, influenced the formation of the chromatin fiber and also the activity of genes.

"We found that the linker histone bound to chromatin in yeast, which we use as a model eukaryote, under conditions where virtually all the genes in the organism were inactive. It was widely believed that the binding of the linker histone caused the inactivation of genes. We studied the relationship between the amount of linker histone bound in the vicinity of each gene and the expression of that gene for all the genes in yeast, using genomic techniques. We made the surprising discovery that even through the linker histone preferentially bound to genes under conditions where the genes were shut off, this inactivation of genes was not caused by the binding of the linker histone and folding of the chromatin,” said Prof. Patterton.

He said: “Instead our data strongly suggested that the observed anti-correlation was due to the movement of enzymes along the DNA molecule, involved in processing the information in genes for the eventual manufacture of proteins. This movement of enzymes displaced the linker histones from the DNA. This finding now requires a rethink on aspects of how packaging of DNA influences gene activity."

Prof. Patterton said that his research group, using the Facility for Genomics and Proteomics as well as the Bioinformatics Node at the UFS, was currently busy with follow-up studies to understand how other proteins in nucleosomes affected the activities of genes, as well as with projects to understand how chemicals found in red wine and in green tea extended lifespan. "We are certainly having a marvelous time trying to understand the fundamental mechanisms of life, and the UFS is an exciting place to be if one was interested in studying life at the level of molecules," he said.

Media Release
Issued by: Lacea Loader
Assistant Director: Media Liaison
Tel: 051 401 2584
Cell: 083 645 2454
E-mail: loaderl.stg@ufs.ac.za
18 September 2008

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