**6. Microsatellite markers**

lambs, providing slaughtering when the animals are between 4 and 8 months, weighing between 30 and 40 kg, generating high carcass yield, up to 50%, and in addition males and

These sheep also features highlighted in relation to the reproductive performance when compared to other breeds of sheep created in Brazil. With reproductive activity during the entire year, females do not show reproductive seasonality, and they can produced more than

The male sheep also have reproductive seasonality, but only when there is little variation of photoperiod, as in the tropics. Moreover, the variation of breed and environmental factors are

As Pantaneiro sheep are not considered a breed, studies of molecular, genetic, and phenotypic characterization are needed in order to prove the differences between these animals and the other breeds. More studies are required to demonstrate the body, production and reproduction

Through indiscriminate crossbreeding with exotic breeds, mainly imported from Africa and Europe, it was put at risk the existence and preservation of naturalized breeds that are now important genetic heritage [28]. These animals have characteristics which may be considered useful both from the productive point of view and adaptive such as tolerance or resistance to diseases and parasites and adaptive wide variations related to the availability and quality of food and water. Therefore, the animals best adapted and/or more resistant survived and reproduced to the present day. Thus, the naturalized breeds are a result of the process of natural

Research aimed at the conservation and breeding of naturalized breeds that are important for the selection of animals for the purpose of controlling intersections, avoiding inbreeding, and indiscriminate crossbreeding that thus purebreds are preserved. Therefore, it is necessary to seek a production system that makes evident its potential, so that they are recognized by the creators and that they perceive the possibility of the use of local breeds for higher returns

Studies related to knowledge of adaptive characteristics of different breeds to the environment can sustain production systems in livestock based on adapted breeds, reducing the impact on

With recent technological developments, new molecular tools were developed in order to understand the origin and domestication process of domestic species. These tools helped the discovery of evolutionary relationships, taxonomy, and demographics of a wide variety of species, providing important support both in identifying priority areas for conservation programs and in the understanding of genetic diversity in domestic and wild species threat‐

the environment and receiving better products for consumption.

females have similar productive performance [19].

characteristics of these animals [27].

**5. Genetic diversity**

42 Livestock Science

selection over the years.

ened with extinction [3].

[29].

1.5 lamb per year, unlike the females of other breeds [19, 25, 26].

also crucial to the reproductive performance of animals [19].

Microsatellites are the most widely used marker for the study of genetic diversity and population structure of domestic animals [30]. The abundance of this marker along the genome, its high degree of polymorphism and codominance are the main features that make it an important tool for genomic analysis.

Through the evaluation of eight microsatellite loci in five breeds of unrelated sheep (Rom‐ ney, Border Leicester, Suffolk, Awassi, Australian, and New Zealand Merino) was found highly significant differences in allele frequencies between individuals, indicating that the genotyping using microsatellite can be a useful tool for examining the evolutionary relation‐ ships between the breeds [31]. Studies using microsatellite markers to characterize genotyp‐ ic and assessments of genetic diversity of sheep described in Spanish breeds, determined the genetic relationship between Swiss breeds. In these studies, microsatellites were efficient to evaluate genetic diversity and demonstration of the genetic diversity between the animals involved [32, 33].

Several studies have shown the use of microsatellite markers in genetic diversity studies of native animals of Brazil. In a study using 27 microsatellite markers to analyze the genetic variability of native breeds of goats in Brazil, the result showed that all microsatellites were polymorphic and showed a high capacity for genetic characterization of these breeds [34]. In another study, microsatellite markers for 18 loci in studies of genetic diversity of sheep naturalizes and exotic in Brazil were used (Santa Inês, Bergamácia Wide Tail, Morada Nova and Somali) and the results showed the efficiency of these markers in the characterization of these breeds because all breeds differed significantly, although they presented low genetic variability [2].

A study with 717 animals was determined the variability of 20 microsatellites in 14 Portuguese sheep breeds. Analysis of these results allowed us to assess the degree of structure of the Portuguese population of sheep and estimate parameters of genetic diversity in each of the breeds [35].

Thus, microsatellites have proven marker of excellence for characterization of new naturalized breeds [36], as well as to genetic variability of population studies [37, 38]. A recent study identified an approach to facilitate the merger of microsatellite data for cross‐country com‐ parison of genetic resources when samples are evaluated in different laboratories. This approach can facilitate the merger and analysis of microsatellite data for cross‐country comparison and extend the utility of previously collected molecular markers. In addition, this analysis can be used in new and existing conservation programs [39].

Recent research analyzes genetic diversity and population structure among varieties of sheep. Therefore, nuclear microsatellite markers and regions of mitochondrial DNA are used [40].
