Nav: Home

Genetic analysis uncovers 4 species of giraffe, not just 1

September 08, 2016

Up until now, scientists had only recognized a single species of giraffe made up of several subspecies. But, according to the most inclusive genetic analysis of giraffe relationships to date, giraffes actually aren't one species, but four. For comparison, the genetic differences among giraffe species are at least as great as those between polar and brown bears.

The unexpected findings reported in the Cell Press journal Current Biology on September 8 highlight the urgent need for further study of the four genetically isolated species and for greater conservation efforts for the world's tallest mammal, the researchers say.

"We were extremely surprised, because the morphological and coat pattern differences between giraffe are limited," says Axel Janke, a geneticist at the Senckenberg Biodiversity and Climate Research Centre and Goethe University in Germany. Giraffes are also assumed to have similar ecological requirements across their range, he added, "but no one really knows, because this megafauna has been largely overlooked by science."

Giraffes are in dramatic decline across their range in Africa. Their numbers have dropped substantially over the last three decades, from more than 150,000 individuals to fewer than 100,000. Despite that, the researchers say that there has been relatively little research done on giraffes in comparison to other large animals, such as elephants, rhinoceroses, gorillas, and lions.

About five years ago, Julian Fennessy of Giraffe Conservation Foundation in Namibia approached Janke to ask for help with genetic testing of the giraffe. Fennessy wanted to know how similar (or not) giraffes living in different parts of Africa were to each other, whether past translocations of giraffe individuals had inadvertently "mixed" different species or subspecies, and, if so, what should be done in future translocations of giraffes into parks or other protected areas.

In the new study, Janke and his research group examined the DNA evidence taken from skin biopsies of 190 giraffes collected by Fennessy and team all across Africa, including regions of civil unrest. The extensive sampling includes populations from all nine previously recognized giraffe subspecies.

The genetic analysis shows that there are four highly distinct groups of giraffe, which apparently do not mate with each other in the wild. As a result, they say, giraffes should be recognized as four distinct species. Those four species include (1) southern giraffe (Giraffa giraffa), (2) Masai giraffe (G. tippelskirchi), (3) reticulated giraffe (G. reticulata), and (4) northern giraffe (G. camelopardalis), which includes the Nubian giraffe (G. c. camelopardalis) as a distinct subspecies. The elusive Nubian giraffe from Ethiopia and the South Sudan region was the first described some 300 years ago, Fennessy says, and is now shown to be part of the northern giraffe.

The discovery has significant conservation implications, the researchers say, noting that the International Union for Conservation of Nature and Natural Resources (IUCN) Species Survival Commission Giraffe and Okapi Specialist Group recently submitted an updated proposed assessment of the giraffe on the IUCN Red List taking into consideration their rapid decline over the last 30 years.

"With now four distinct species, the conservation status of each of these can be better defined and in turn added to the IUCN Red List," Fennessy says. "Working collaboratively with African governments, the continued support of the Giraffe Conservation Foundation and partners can highlight the importance of each of these dwindling species, and hopefully kick start targeted conservation efforts and internal donor support for their increased protection.

"As an example," he adds, "northern giraffe number less than 4,750 individuals in the wild, and reticulated giraffe number less than 8,700 individuals--as distinct species, it makes them some of the most endangered large mammals in the world."

Janke and Fennessy say that they are now analyzing the amount of gene flow between the giraffe species in greater detail. In addition to expanding the ecological and species distribution data, they want to better understand the factors that limit gene flow and the giraffes' differentiation into four species and several subspecies.
-end-
This study was supported by the State of Hesse's funding program LOEWE, the Leibniz Association, the Giraffe Conservation Foundation, the Leiden Conservation Foundation, the Auckland Zoo, and various African government partners and international supporters.

Current Biology, Fennessy et al.: "Multi-locus Analyses Reveal Four Giraffe Species Instead of One" http://www.cell.com/current-biology/fulltext/S0960-9822(16)30787-4

Current Biology (@CurrentBiology), published by Cell Press, is a bimonthly journal that features papers across all areas of biology. Current Biology strives to foster communication across fields of biology, both by publishing important findings of general interest and through highly accessible front matter for non-specialists. Visit: http://www.cell.com/current-biology. To receive Cell Press media alerts, contact press@cell.com.

Cell Press

Related Conservation Articles:

Targeted conservation could protect more of Earth's biodiversity
A new study finds that major gains in global biodiversity can be achieved if an additional 5 percent of land is set aside to protect key species.
Conservation endocrinology in a changing world
The BioScience Talks podcast (http://bioscience.libsyn.com) features discussions of topical issues related to the biological sciences.
Marine conservation must consider human rights
Ocean conservation is essential for protecting the marine environment and safeguarding the resources that people rely on for livelihoods and food security.
Mapping Biodiversity and Conservation Hotspots of the Amazon
Researchers have used remote sensing data to map out the functional diversity of the Peruvian Andes and Amazon basin, a technique that revealed hotspots for conservation.
Mapping biodiversity and conservation hotspots of the Amazon
Researchers have used remote sensing data to map out the functional diversity of the Peruvian Andes and Amazon basin, a technique that revealed hotspots for conservation.
Internet data could boost conservation
Businesses routinely use internet data to learn about customers and increase profits -- and similar techniques could be used to boost conservation.
Why conservation fails
The only way for northern countries to halt deforestation in the South is to make sure land owners are paid more than it costs them to conserve the forest.
Visitors to countryside not attracted by conservation importance
Countryside visitors choose where to go based on the presence of features such as coastline, woodland or abundant footpaths, rather than a site's importance to conservation, according to new research.
In communicating wildlife conservation, focus on the right message
If you want people to care about endangered species, focus on how many animals are left, not on the chances of a species becoming extinct, according to a new study by Cornell University communication scholars.
New partnership to boost Asia-Pacific conservation
The University of Adelaide and global organization Conservation International (CI) today announced a strategic partnership that will help boost conservation efforts in the Asia-Pacific region, including a global conservation drone program.

Related Conservation Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...