The mosaic genome of indigenous African cattle as a unique genetic resource for African pastoralism

Professor Heebal Kim (Department of Agricultural Biotechnology)

Kwondo Kim, Taehyung Kwon, Tadelle Dessie, DongAhn Yoo, Okeyo Ally Mwai, Jisung Jang, Samsun Sung, SaetByeol Lee, Bashir Salim, Jaehoon Jung, Heesu Jeong, Getinet Mekuriaw Tarekegn, Abdulfatai Tijjani, Dajeong Lim, Seoae Cho, Sung Jong Oh, Hak-Kyo Lee, Jaemin Kim, Choongwon Jeong, Stephen Kemp, Olivier Hanotte, and Heebal Kim. The mosaic genome of indigenous African cattle as a unique genetic resource for African pastoralism. Nature Genetics. 2020. DOI: 10.1038/s41588-020-0694-2

 

Cattle play an important role across African economies and societies as a primary source of wealth. Today, at least 150 indigenous cattle breeds have been recognized across the different agro-ecologies of the African continent, each with unique phenotypic and adaptive characteristics shaped by B. taurus × B. indicus (zebu) admixture.

Fig. 1 Historical and geographical origin of African cattle breeds in this study.

The research team of Professor Heebal Kim collaborated with scientists at the International Livestock Research Institute (ILRI); Rural Development Agency (RDA, Republic of Korea); University of Khartoum (Sudan); The Center of Tropical Livestock Genetics and Health (CTLGH, Scotland); Swedish University of Agricultural Sciences (Sweden); and the University of Nottingham (United Kingdom) sequence and analyzed the genomes of 172 indigenous African cattle to learn how cattle rapidly evolved during the last millennia with traits that allowed them to thrive across the continent (Fig. 1.).

The genome sequencing work conducted by the scientists revealed that indigenous pastoralist herders in the Horn of Africa began breeding the Asian zebu cattle with local taurine breeds about a thousand years ago. In addition, the research team identified selection signatures with an excess of taurine or indicine ancestry in African hybrid cattle. One example of the selection signatures is observed at autosome 7 where genes related to heat tolerance were identified with excess of indicine ancestry (Fig. 2), while regulatory element related to tolerance against trypanosomosis was identified in African taurine-specific loci at autosome 25. These findings support that zebu offered traits that would allow cattle to survive in hot, dry climates, while the taurine provided cattle with the ability to endure humid climates where vector-borne diseases like trypanosomiasis are common.

Fig. 2 Example of candidate selective loci on BTA7 with an excess of indicine ancestry.

In conclusion, despite the environmental complexity of the African continent, and cattle domestication outside its geographic area, we currently find domestic cattle across all African agro-ecologies. The results presented here support that taurine × indicine admixture events followed by taurine and indicine ancestry selection across the genome is at the root of the success of African cattle pastoralism.

This study was published in Nature genetics volume 52, pages 1099-1110(2020)