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04 December 2017

Surprise in the Kangaroo Family Tree – An Outsider Is a Close Relative, After All...

17 November 2017

European forests might not be realizing their full potential ...

14 November 2017

Partnertausch als Überlebensstrategie – Flechten passen sich durch Algenwechsel an neues Klima an ...

20 October 2017

Shallow soils promote savannas in South America...

07 September 2017

Rising winter temperatures contributed to the decline of the brown bear in Europe...

03 July 2017

Elevational range limits of alpine trees not solely determined by climate...

30 June 2017

Areas affected by fire are decreasing globally...

13 June 2017

Global hotspots for alien species are island and coastals regions...

31 May 2017

Downsizing in animal communities leads to functional decay in tropical forests...

24 May 2017

Zebras follow their memory when migrating ...

11 May 2017

Picky birds are most flexible...

09 May 2017

Open Day at Senckenberg Biodiversity and Climate Research Centre...

27 April 2017

Auf dem Gipfel der Evolution – Flechten bei der Artbildung zugeschaut...

19 April 2017

Bears breed across species borders...

30 March 2017

Ground water depletion due to international trade threathens food supply world-wide...

27 March 2017

Methan emissions from cows could rise by 70 per cent until 2050...

27 February 2017

New insights into the mechanisms into how ungulates got bigger in the Neogene...

20 February 2017

More warm-dwelling Animals and Plants as a Result of Climate Change ...

15 February 2017

Alien species on the rise worldwide...

02 February 2017

Partnerwahl bei Flechten – Warmes Klima macht wählerisch...

17 January 2017

Spiel mit dem Feuer – wie Eiszeitjäger das Landschaftsbild Europas prägten...

11 January 2017

How far do invasive species travel?...

04 January 2017

Domino effect: The loss of plant species triggers the extinction of animals...

Press Releases

Bears breed across species borders

Frankfurt, Germany, April 19th, 2017. Senckenberg scientists have sequenced the entire genomes of four bear species, making it now possible to analyze the evolutionary history of all bears at the genome level. It shows that gene flow, or gene exchange, between species by extensive hybridization, is possible between most bear species - not only polar and brown bear. The DNA samples of different bear species came from different European zoos, underlining their importance not only for conservation, but also for research. The study published today in "Nature Scientific Reports" also questions the existing species concept in general, because other genome studies too have, frequently found gene flow among species.

Pizzly, grolars or "capuccino bears" are common names of the offspring resulting from the mating of grizzly bears (Ursus arctos) and polar bears (Ursus maritimus). "Such hybrids among bears are not as rare as we have hitherto assumed," says Prof. Dr. Axel Janke of the Senckenberg Biodiversity and Climate Research Center in Frankfurt. In a large-scale analysis, a team of scientists led by the German evolutionary geneticist has sequenced six complete bear genomes. Each genome is about 2.5 billion base pairs large. "With these new data of the sun bear, sloth bear, Asiatic black bear and spectacled bear, we now have the genomes of all known bear species," adds Janke.

It has previously been assumed that the number of hybrids between polar and brown bears is increasing due to climate change, because brown bears invade northern regions. The new results show however that an abundant flow of genes among different bear species occurred to a good deal in the past. Hybrids are thus not necessarily linked to climate change. "Bears can form hybrids in different combinations," explains Janke, and adds: "We knew this from zoos. In the wild, so far this was only observed for polar bears and brown bear as well as Asiatic black and sun bear."

The new genomic data also show that there must have even been gene flow between the polar and sun bears. However, the two species live in geographically completely distinct areas and thus have never met. The researchers are able to explain this alleged contradiction by suggesting that an "intermediate host" or "vector species" has passed the genes on in various directions. The brown bear is an ideal candidate for this role as conveyor of genes: his geographic distribution overlaps with that of all other bear species and its genome contains polar bear genes. "By hybridization the brown bear could pass these polar bear genes on to other bear species in Asia", adds the Frankfurt scientist.

The detected gene flow among bears also questions the basic biological concept of a species. The biological species definition assumes that different species cannot produce offspring in the wild or that hybrid offspring are sterile. The best-known example of this is the mule – a hybrid between a horse and a donkey. However, it has been observed that grolars, the hybrids between polar and grizzly bears, are often fertile. Janke: "We have to ask ourselves: Does the species concept still hold true, given there is evidence of gene flow not only in bears, but also in other animals? Therefore, what do we need to protect for the future – species or genomic diversity? ".

It is certain that the amazing progress of genomics and its technology will also question other fundamental principles of biology and fuel research. "Evolution creates genetic differences and adaptations, whether we call these differences species or not, is less important. What we must preserve, however, is genetic variation to protect diversity and to allow adaptation to future environmental changes", Janke states.

Press images

Pizzly Andrew Derocher

Hybrids between bear species such as the pizzly or grolar bear, which is a mixture of polar and grizzly bear, are not as rare as hithero assumed. Copyright: Andrew E. Derocher

Northern Brown Bear Alexander Kopatz

Brown bears may be intermediate hosts of genes between the geographically separated polar and sun bears because the brown bear distribution area overlaps with both of the species. Copyright: Alexander Kopatz

Contact

Prof. Dr. Axel Janke
Senckenberg Biodiversity and Climate Research Centre &
Goethe-University Frankfurt a.M.
Phone +49 (0)69- 7542 1842
Axel.janke@senckenberg.de

Sabine Wendler
Press officer
Senckenberg Biodiversity and Climate Research Centre
Phone +49 (0)69- 7542 1818
pressestelle@senckenberg.de

Publication

Kumar, V. et al. (2017): The evolutionary history of bears is characterized by gene flow across species. Scientific Reports 7, 46487, doi: 10.1038/srep46487

Press images may be used at no cost for editorial reporting, provided that the original author’s name is published, as well. The images may only be passed on to third parties in the context of current reporting.

To study and understand nature with its limitless diversity of living creatures and to preserve and manage it in a sustainable fashion as the basis of life for future generations – this has been the goal of the Senckenberg Gesellschaft für Naturforschung (Senckenberg Nature Research Society) for 200 years. This integrative “geobiodiversity research” and the dissemination of research and science are among Senckenberg’s main tasks. Three nature museums in Frankfurt, Görlitz and Dresden display the diversity of life and the earth’s development over millions of years. The Senckenberg Nature Research Society is a member of the Leibniz Association. The Senckenberg Nature Museum in Frankfurt am Main is supported by the City of Frankfurt am Main as well as numerous other partners. Additional information can be found at www.senckenberg.de.

200 years of Senckenberg! 2017 marks Senckenberg’s anniversary year. For 200 years, the society, which was founded in 1817, has dedicated itself to nature research with curiosity, passion and involvement. Senckenberg will celebrate its 200-year success story with a colorful program consisting of numerous events, specially designed exhibitions and a grand museum party in the fall. Of course, the program also involves the presentation of current research and future projects. Additional information can be found at: www.200jahresenckenberg.


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