Assessing patterns of genetic admixture between sheep breeds: Case study in Algeria

Abstract

In developing countries, cross‐breeding between local breeds and indigene or exotic breeds represents one of the main threats to the livestock diversity, leading to genetic dilution and loss of unique allelic combination underlying essential local adaptive traits. In this study, two Algerian sheep breeds, known to be highly admixed, were considered as a case study, to demonstrate how combination of different methodologies coupled with the use of specific softwares can be efficient to assess the spatial structuration of a hybrid zone, even in a case of extreme admixture. A fine sampling covering distribution areas of both breeds was implemented in order to study the admixture area and adjacent zones from a phenotypic (i.e., 19 quantitative traits were considered) and a genetic point of view (i.e., 21 microsatellites markers were used). Both approaches gave concordant patterns, highlighting areas with sheep most differentiated (or less admixed) for each breed. In detail, the region of Biskra appeared as the most preserved for the Ouled‐Djellal breed and the northwest of Laghouat was identified as the most preserved area for the Rembi breed. The approach proposed in the study offers a low‐cost solution to identify the most representative flocks of a breed, allowing the implementation of efficient conservation plans.

How have sheep breeds differentiated from each other in Morocco? Genetic structure and geographical distribution patterns

“…The weak geographical distribution of the genetic diversity found in the current study is consistent with previous studies on sheep breeds of Algeria using microsatellite data [ 60 ]. In addition, using single nucleotide polymorphisms, Belabdi et al [ 21 ] revealed a high level of homogenization, such that some breeds with different origins appeared to be genetically undistinguishable.…”

Inference of Breed Structure in Farm Animals: Empirical Comparison between SNP and Microsatellite Performance

“…Indeed, sampling must be sufficiently broad to cover the global range of the breeds. Only this type of sampling will make it possible to really grasp the situation, knowing that a whole range of situations can be encountered between the preserved populations and the diluted populations [46]. The current cost of genetic chips is hardly compatible with the need for broad sampling, and once again emphasizes the appeal of using microsatellites to provide a first rough, but broad picture of the national situation (see [47]).…”

Refining the genomic profiles of North African sheep breeds through meta-analysis of worldwide genomic SNP data

“…However, the differentiation of overall Maghrebin from Egyptian and Libyan sheep with affinity to Middle Eastern and Asian breeds may suggest two complementary hypotheses. According to the first hypothesis, the Tunisian and Algerian Barbarines are influenced by local thin-tailed breeds by genetic intermixing of fat- and thin-tailed breeds that appears to be a common feature in North African sheep, especially in the northwestern region ( 28 , 52 , 53 ). The second hypothesis suggests that the geographic isolation by adaptation to different eco-climates as well as different cultural practices have differentiated native sheep populations ( 22 ).…”