The dama gazelle (Nanger dama) is the largest of the gazelles. They are 160 to 170 centimeters long, 90 to 120 centimeters tall and weigh 50 to 85 kilograms. Dama gazelles’ horns are S-shaped and, for males, can grow to 20 to 40 centimeters long. Males are noticeably larger than females, and their horns are much longer.
Dama gazelles inhabit the foothills, plateaus and steppes of the Sahara and Sahel of North Africa. They are highly social, diurnal animals. Their social organization largely depends on the season. During the dry season, groups migrate from the Sahara to the more mesic Sahel, where they occur as solitary animals or in small groups. Other times, they gather in mixed groups of 10 to 20 individuals, including a dominant male.
Members of the herd spend their days moving about in search of edible vegetation and water sources. Dama gazelles are quite drought tolerant and mostly obtain water from the various shrubs and coarse desert grasses they consume. When the rainy season arrives, these animals migrate to the Sahara, where they gather in large herds.
Dama gazelles were once numerous across a range that spanned from Morocco to Senegal in the west to Sudan in the east. The number of dama gazelles began to significantly decline in the 1950s due to overhunting and habitat loss. By 1980, these animals had disappeared from many areas of their range, but were found to be abundant in some local regions. In 2001, studies were conducted that showed that the total number of remaining dama gazelles was extremely small and the range very fragmented. In addition to hunting and habitat loss, increasing aridity due to gradual climate change may also affect the long-term survival of the species in the wild.
The dama gazelle is categorized as a critically endangered species by the International Union for Conservation of Nature. Only about 2,600 individuals remain in the world. Most dama gazelles are maintained and managed in ex situ herds within zoos, reserves and private ranches in Europe, the Middle East and the United States.
Given dama gazelles’ small population size, maintaining genetically diverse populations and avoiding inbreeding are top priorities for conservationists. Animals from ex situ populations can be reintroduced to reserves in the Sahelian and Saharan regions and help establish resilient populations across their former range.
Today, we are delighted to share the chromosome-length assembly representing one of the three subspecies of the dama gazelle, the addra gazelle (Nanger dama ruficollis). The draft contig-based assembly was produced with 10X Genomics linked-read sequencing and assembled using Supernova version 2.0. The genetic material used to generate the contig-based assembly and the Hi-C data for chromosome-length scaffolding was collected from a male addra gazelle belonging to an ex situ herd managed at the Smithsonian Conservation Biology Institute in Front Royal, Virginia, USA. In conjunction with international collaborators, we are using this assembly to investigate a number of questions related to the conservation genomics of this unique gazelle. Check out the interactive Hi-C contact map of the assembled chromosomes below!
The Smithsonian Conservation Biology Institute (SCBI) spearheads research programs at its headquarters in Virginia, the Smithsonian’s National Zoo in Washington, D.C., and at field research stations and training sites worldwide. SCBI scientists tackle some of today’s most complex conservation challenges by applying and sharing what they learn about animal behavior and reproduction, ecology, genetics, migration and conservation sustainability. Findings from these studies provide critical data for the management of populations in human care and valuable insights for the conservation and management of wild populations.
This update was written by Pasha Dobrynin, Budhan Pukazhenthi and Klaus-Peter Koepfli of the Smithsonian Conservation Biology Institute.