Genomics is evidence that there are four species of giraffe
Madrid, 7 (Europe Press)
Visually, they are barely distinguishable, but new genetic analyzes show that there are actually four different species of giraffe and seven subspecies.
This result was obtained by an international team led by Professor Axel Yankee of the LOEWE Center for Translational Genomics of Biodiversity. According to their extensive analyzes of the genome, the four giraffe subspecies have evolved separately for thousands of years. Relationships within the giraffe genus have been discussed before. For a long time it was assumed that there was one species, then four, and then three types. The published study Current Biology provides new knowledge about giraffe evolution and relevant information for properly preserving them in Africa.
In a statement, Professor Janki explains: “Genomics, which consists of studying all the genetic information of an organism, opens up new possibilities and can broaden our perspective on species and their evolution, as it has now happened in the case of giraffes.”
One species should be the long-necked African mammal, the giraffe, which has been generally accepted for a long time. However, preliminary 2016 genetic studies from Janke’s lab indicated that there is not one, but rather four different species of giraffe. This groundbreaking result, obtained jointly with the Giraffe Conservation Foundation (GCF), is the subject of a controversial debate among researchers and conservationists. Now, genome analyzes support the four species model.
Analysis of nearly 200,000 sites in the DNA of a total of 50 giraffes confirm four species, namely the northern giraffe, the southern giraffe, the reticulated giraffe and the Maasai giraffe. It consists of a total of seven subspecies. The data also shows that the four giraffe subspecies began to develop separately from each other between 230,000 and 370,000 years ago. There is very little gene flow and mixing between them. This means that the different species generally do not mate in the wild. However, in captivity, this is possible under certain conditions.
“The results of the genome analysis are of great importance in the preservation of giraffes,” says Dr. Julian Vinacy, director of GCF and co-author of the study. The population has decreased dramatically in the last century to around 117,000 wild giraffes. Vinici: “It is now clear that the remaining giraffes belong to four different species. This is further exacerbating the situation. For example, we estimate that there are fewer than 6000 northern giraffes remaining in the wild. As a species, it is one of the most threatened large mammals in the world.” .
Giraffes are found in savannahs in sub-Saharan Africa from Niger through Kenya and Namibia to southern Africa. These herbivores reach a height of six meters and are the largest land mammals in the world. Their livelihoods are deteriorating in many places due to the increasing demand for agricultural land. Illegal fishing and politically difficult conditions complicate their protection. The International Union for Conservation of Nature (IUCN) classifies giraffes as “endangered” on its Red List of Threatened Species. The four species model has not been taken into account yet, a fact that could change now.
“The data available is more informative than ever,” says Raphael Coimbra, researcher at SBiK-F (Senckenberg Institute for Biodiversity and Climate Research) and author of the study. “Our analyzes of the genome are based on much more genetic data than previous studies.”
In their analyzes, the researchers compared giraffe genomes of all previously considered species and subspecies from a total of 12 African countries and zoos. Therefore, the genome of the Kordofan giraffe, a subspecies of the endangered northern giraffe, has been completely sequenced for the first time.