BACKGROUND : Understanding the history of cattle breeds is important because it provides the basis for developing
appropriate selection and breed improvement programs. In this study, patterns of ancestry and admixture in Afrikaner,
Nguni, Drakensberger and Bonsmara cattle of South Africa were investigated. We used 50 K single nucleotide
polymorphism genotypes that were previously generated for the Afrikaner (n = 36), Nguni (n = 50), Drakensberger
(n = 47) and Bonsmara (n = 44) breeds, and for 394 reference animals representing European taurine, African taurine,
African zebu and Bos indicus.
RESULTS AND DISCUSSION : Our findings support previous conclusions that Sanga cattle breeds are composites
between African taurine and Bos indicus. Among these breeds, the Afrikaner breed has significantly diverged from its
ancestral forebears, probably due to genetic drift and selection to meet breeding objectives of the breed society that
enable registration. The Nguni, Drakensberger and Bonsmara breeds are admixed, perhaps unintentionally in the case
of Nguni and Drakensberger, but certainly by design in the case of Bonsmara, which was developed through crossbreeding
between the Afrikaner, Hereford and Shorthorn breeds.
CONCLUSIONS : We established patterns of admixture and ancestry for South African Sanga cattle breeds, which provide
a basis for developing appropriate strategies for their genetic improvement.
Additional file 1: Table S1. Description of samples included in the
analyses. This table provides information about the samples used in this
study such as the sample size, samples origin, land of origin and the references
where the sample were previously characterized.
Additional file 2: Figure S1 Graph of the inferred relationships between
24 cattle breeds without adding migration edges. For full definition of
breeds see Additional file 1: Table S1. This graph shows the genetic relationship
of South African cattle breeds in relation to the cattle breeds of
the world before migration edges were sequentially added.
Additional file 3: Table S2. Explained covariance between populations
for the ancestral graph with 10 migration edges. This data shows the
changes in explained covariance between the populations as the number
of migration edges added to the ancentral graph increases. It shows that
after adding 10 migration edges, no significant changes were oberved in
Additional file 4: Table S3. Some significant f4 statistics for South African
Sanga cattle. This data shows some of the significant f4 statistics and
indicates the presence of gene flow between these breeds.