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Students hear from textbook writer about conservation genetics

02 August 2022 | Story Leonie Bolleurs | Photo Leonie Bolleurs

Genetics lecture — Alistair Naidoo, second-year master’s student in Conservation Genetics and full-time technician in the Department of Genetics; Prof Paul Grobler, Head of the Department of Genetics; Prof Gordon Luikart; and Hannah Janse van Vuuren, third-year master’s student in Conservation Genetics.

It is an important and exciting time to be doing research in conservation genetics. This is according to Prof Gordon Luikart, Professor of Conservation Ecology and Genetics at the Flathead Lake Bio Station at the University of Montana in the United States.

Prof Luikart, whose primary research focus is the application of genetics to the conservation of natural and managed populations, recently delivered a lecture, The Expanding Role of Genetics/omics in Wildlife Research and Conservation, on the Bloemfontein Campus of the University of the Free State (UFS). The lecture, hosted by the Department of Genetics, was attended by a group of students and lecturers in conservation and a number of related fields.

He is one of the leading scientists in the field of conservation genetics, including integration of genomics in conservation projects. He is also co-author of the textbook Conservation and the Genomics of populations – the current prescribed textbook for GENE3744.

Species threatened with extinction

In 2008, the International Union for Conservation of Nature (IUCN) stated that approximately 10-20% of all vertebrate and plant species are threatened with extinction over the next few decades. In 1984, American biologist Edward O Wilson also said that it will take millions of years to correct the ongoing loss of genetics and species diversity caused by the destruction of natural habitats. “This is the folly our descendants are least likely to forgive us.”

Prof Luikart is of the opinion that genetics has enormous potential to help manage wildlife and prevent extirpation. “My research works to realise this potential and help wildlife managers conserve populations and ecosystems,” he says.

Conservation managers and biologists have understood the risks of inbreeding for more than 100 years. In his lecture, one of the aspects of genetic conservation he focused on, was the negative effects of inbreeding and how this can be reversed using genetic rescue.

With the genetic rescue study, they found that the gene flow into recently isolated populations can increase individual fitness and population growth. He proposed that conservation managers should consider genetic principles and rescue as practical and important tools.

Prof Luikart also provided a list of information that can be retrieved from molecular genetic data to help conservation managers. This includes intel on census and effective population size, gene flow and dispersal, local adaptation and selection, forensics, genetic identification and law enforcement, and disease ecology and transmission.

Non-invasive genetic monitoring

In terms of detecting gene flow, he focused on a study about non-invasive genetic monitoring that was conducted in the Yellowstone Park. Prof Luikart and a group of students collected the shed hair and faeces of the grizzly bear, obtained from trees and hair traps, which were used as a source of DNA.

They established, for instance, that inbreeding depression is more common and stronger than previously thought in natural populations. Genetic monitoring, using non-invasive methods as described, has been found to be an effective tool that conservation managers should consider for detecting inbreeding and loss of genome-wide variation.

His research on the bighorn sheep, the alpine ibex, and the black bear informed most of the findings he discussed during his lecture.

News Archive

Research by experts published in Nature

2011-06-02

The members of the research group are, from the left, front: Christelle van Rooyen, Mariana Erasmus, Prof. Esta van Heerden; back: Armand Bester and Prof. Derek Litthauer.
Photo: Gerhard Louw

A research article on the work by a team of experts at our university, under the leadership of Prof. Esta van Heerden, and counterparts in Belgium and the USA has been published in the distinguished academic journal Nature today (Thursday, 2 June 2011).

The article – Nematoda from the terrestrial deep subsurface of South Africa – sheds more light on life in the form of a small worm living under extreme conditions in deep hot mines. It was discovered 1,3 km under the surface of the earth in the Beatrix Goldmine close to Welkom and is the first multi-cellular organism that was found so far beneath the surface of the earth. The worm (nematode) was found in between a rock face that is between 3 000 and 12 000 years old.

The research can shed some new light on the possibility of life on other planets, previously considered impossible under extreme conditions. It also expands the possibilities into new areas where new organisms may be found.

These small invertebrates live in terrestrial soil subjected to stress almost for 24 hours They live through sunshine, rain, scorching temperatures and freezing conditions. Through time they developed a means to cope with harsh conditions. Terrestrial nematodes (roundworms, not to be confused or related to earthworms) are among those very tough small invertebrates that deal with those conditions everywhere. After insects they are the most dominant multi-cellular (metazoan) species on the planet having a general size of 0,5 to 1 mm and are among the oldest metazoans on the planet, Nature says in a statement on the article.

They inhabit nearly every imaginable habitat form the deep seas to the acid in pitcher . Some nematodes simply eat bacteria and these are the ones we study here. Terrestrial nematodes have developed a survival stage that can take them through hard times (absence of food, extreme temperatures, too little oxygen, crowding, and more).

At the head of the research was Prof. Gaetan Borgonie of the Ghent University in Belgium and a world leader in the discipline of nematode research. He was brought into contact with the South African research leader, Prof. Esta van Heerden, who set up a cooperation agreement with the University of Ghent and Prof. Borgonie. Prof. Van Heerden manages the Extreme Biochemistry group at the UFS and the research was funded by several research grants.

The search for worms began in earnest in 2007, but it was soon clear that the sampling strategy was insufficient. A massive sampling campaign in 2008-2009 in several mines led to the discovery of several nematodes and the new nematode species Halicephalobus mephisto. It is named after the legend of Faust where the devil, also known as the lord of the underworld is called Mephistopheles.

Nature says special filters had to be designed and installed on various boreholes. Unfortunately, there is no easy way of finding a magic formula and designs had to be adapted by trial and error; improving existing designs all the time. The work of the UFS Mechanical Workshop, which manufactured, adapted and helped design it, was crucial in this respect. Filters were left on the holes for varying periods, sometimes for a few hours and sometimes for months. Prof. Derek Litthauer from the UFS played a big role in sampling, filter designs and coming up with ideas for names for the new nematode with Prof. Borgonie.

Research showed that the nematodes can live in the deep for up to 12 000 years. Three students – Armand Bester, Mariana Erasmus and Christelle van Rooyen from the UFS – did the work on this.

The importance of multi-cellular animals living in the ultra-deep subsurface is twofold: The nematodes graze on the existing bacterial population and influence their turnover. Secondly, if more complex multi-cellular organisms can survive in the deep subsurface on earth, this may be good news when looking for life on other planets where the surface is considered too inhospitable (e.g. Mars). Complex life forms can be found in ecosystems previously thought to be uninhabitable. Nature says this expands the possibilities into new areas where new organisms may be discovered.

Future research will focus on selective boreholes to look for more metazoans, so that a better idea of the complexity of the ecosystems there can be obtained. It will also look for metazoans in the deep subsurface on other continents to determine similarities and differences.

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