**7. Phylogeny and population structure**

Despite the sheep breeds are considered adapted to Brazil and these animals were brought to the country by settlers soon after the discovery, few studies have been conducted in order to discover the origin of these animals.

Knowledge of the population structure combined with information about genetic changes can influence future management actions and can be used to develop strategies for using a breed in a particular ecosystem as a model for genetic improvement programs [41]. Conservation programs using molecular tools are crucial for the providing information about the genetic diversity of locally adapted groups, thus allowing them to be included in production systems for integration of adaptation and rusticity features [12].

Recent molecular tools and technologies have marked the discovery of the origin and domes‐ tication processes of a wide variety of species, using either nuclear or mitochondrial molecular markers. These tools have aided in the understanding of evolutionary relationships, taxonomy, and demography of several species that will provide support to identify the most important areas for conservation programs, in addition to the analysis of genetic diversity in domestic, wildlife, and endangered species [3, 4].

Two studies [42, 43] demonstrated the existence of at least two major haplogroups in *O. aries* from the control region (D‐loop) of mitochondrial DNA (mtDNA) sequencing: one of European origin and another, probably of Asian origin. These results can also be interpreted as two independent domestication events that have occurred for domestic species [44]. Furthermore, it was developed a test based on polymerase chain reaction—restriction fragment length polymorphism (PCR‐RFLP) of mitochondrial cytochrome C oxidase I gene (MT‐COI 6) with the restriction enzyme *Hinf*I (extracted from bacteria *Haemophilus influenza* Rf) in order to more easily identify these two haplogroups HA (Asian origin) and HB (European origin) [43].

The study of the mtDNA region, which can be called DNA barcoding, uses partial DNA sequences of the MT‐COI 6 gene to identify and designate both new species as described previously, helping to unravel the diversity [45].

A study using PCR‐RFLP from MT‐COI 6 gene using HinfI restriction enzyme was performed to molecularly characterize, over the existing haplogroups, some sheep breeds used in the state of Mato Grosso do Sul [8]. The study with the MT‐COI RFLP gene indicated the applicability of this molecular tool to classify most of the animals as belonging to the European haplogroup, highlighting the European origin of the state breeds.

Researchers analyze genetic diversity and population structure among varieties of White, Red, and Black Morada Nova hair sheep from flocks in the northeastern Brazilian semiarid region. In this study, the use of 15 nuclear microsatellite markers and two regions of mitochondrial DNA identified the existence of substantial differences between the Red and White varieties of this sheep and should be used as separate genetic resources and to improve conservation programs [40].

The origin of sheep from some of the breeds in the state of Mato Grosso do Sul, Brazil is important because these are part of the genetic heritage of the state and by knowing their phylogeny it is possible to improve the management of these breeds, aiming its conservation and the use of the productivity of these animals in our environment.

**7. Phylogeny and population structure**

for integration of adaptation and rusticity features [12].

discover the origin of these animals.

44 Livestock Science

wildlife, and endangered species [3, 4].

previously, helping to unravel the diversity [45].

highlighting the European origin of the state breeds.

programs [40].

Despite the sheep breeds are considered adapted to Brazil and these animals were brought to the country by settlers soon after the discovery, few studies have been conducted in order to

Knowledge of the population structure combined with information about genetic changes can influence future management actions and can be used to develop strategies for using a breed in a particular ecosystem as a model for genetic improvement programs [41]. Conservation programs using molecular tools are crucial for the providing information about the genetic diversity of locally adapted groups, thus allowing them to be included in production systems

Recent molecular tools and technologies have marked the discovery of the origin and domes‐ tication processes of a wide variety of species, using either nuclear or mitochondrial molecular markers. These tools have aided in the understanding of evolutionary relationships, taxonomy, and demography of several species that will provide support to identify the most important areas for conservation programs, in addition to the analysis of genetic diversity in domestic,

Two studies [42, 43] demonstrated the existence of at least two major haplogroups in *O. aries* from the control region (D‐loop) of mitochondrial DNA (mtDNA) sequencing: one of European origin and another, probably of Asian origin. These results can also be interpreted as two independent domestication events that have occurred for domestic species [44]. Furthermore, it was developed a test based on polymerase chain reaction—restriction fragment length polymorphism (PCR‐RFLP) of mitochondrial cytochrome C oxidase I gene (MT‐COI 6) with the restriction enzyme *Hinf*I (extracted from bacteria *Haemophilus influenza* Rf) in order to more easily identify these two haplogroups HA (Asian origin) and HB (European origin) [43].

The study of the mtDNA region, which can be called DNA barcoding, uses partial DNA sequences of the MT‐COI 6 gene to identify and designate both new species as described

A study using PCR‐RFLP from MT‐COI 6 gene using HinfI restriction enzyme was performed to molecularly characterize, over the existing haplogroups, some sheep breeds used in the state of Mato Grosso do Sul [8]. The study with the MT‐COI RFLP gene indicated the applicability of this molecular tool to classify most of the animals as belonging to the European haplogroup,

Researchers analyze genetic diversity and population structure among varieties of White, Red, and Black Morada Nova hair sheep from flocks in the northeastern Brazilian semiarid region. In this study, the use of 15 nuclear microsatellite markers and two regions of mitochondrial DNA identified the existence of substantial differences between the Red and White varieties of this sheep and should be used as separate genetic resources and to improve conservation

The origin of sheep from some of the breeds in the state of Mato Grosso do Sul, Brazil is important because these are part of the genetic heritage of the state and by knowing their The Creole sheep has been reared for centuries in the Brazilian states of Rio Grande do Sul and Santa Catarina, where there are two known varieties: Fronteira and Serrana [46]. Considering the geographic distribution of sheep in Brazil and phenotypic similarities between the animals, it is thought that Pantaneiro sheep originated from the Creole sheep, and research has been carried out to determine whether the difference between the groups is sufficient for the Pantaneiro sheep to be recognized as a separate breed [10]. NADH dehydrogenase is one of the main enzymes found in respiratory complexes in mammals. The subunit five (*ND5*) was used to study sheep diversity [47, 46]. The former study determined subspecies of *Ovis ammon* in Mongolia by sequencing this region, and the results suggested the existence of two subspe‐ cies (*O. ammon ammon* and *O. ammon darwini*). The genetic differentiation was found between animals of the Creole sheep in the south of Brazil belonging to the varieties Serrana and Fronteira [44].

Genetic polymorphisms in mitochondrial DNA (mtDNA) reveal haplotype diversity within species, and are therefore a useful tool for establishing phylogenetic relationships at the species level [5] The Pantaneiro breed presents a higher genetic variability than other breeds of sheep reared in tropical altitude regions. Therefore, it is important to develop research that aims at their conservation and genetic improvement [7].

In order to assessed the variation between a population of Pantaneiro sheep in the state of Mato Grosso do Sul and Creole sheep in the south of Brazil through molecular analysis of the mtDNA ND5 region, an study revealed that Creole sheep have a different haplotype compared to Pantaneiro sheep, suggesting that differentiation has occurred between these groups; there‐ fore, more research would be necessary that can be recognized Pantaneiro sheep as a distinct breed [9, 10]. Furthermore, several haplotypes in the Creole sheep were close to the one formed by the Pantaneiro breed animals which may indicate that, although these animals do not share the same haplotype, they belong to the same haplogroup. The geographical region where these animals are found today belonged previously to Paraguay, so it is possible that the Pantaneiro breed has been influenced by Paraguayan breeds and the analysis of its mitochondrial genome might confirm this assumption, by showing their genetic diversity from the Creole.

Thus, the significant differences identified for the mtDNA *ND5* gene between Pantaneiro and Creole sheep may indicate that differentiation has occurred in both breeds; however, further research using other markers is required to investigate this further. Additional management measures need to be carried out in this herd to reduce inbreeding and optimize genetic variation.

Other aspects besides the distribution of genetic diversity have to be taken into account when dealing with conservation strategies of species. Historical, cultural, and traditional aspects about the use of particular breeds are relevant issues. Furthermore, the selection practiced by sheep breeders can favoring alleles for which the surrogate neutral markers used in diversity surveys are not necessarily fully representative.
