This study analyzed four remnant subpopulations of Nordestino horse breed to detect genetic structure and diversity through 14 microsatellite markers. Hair root follicles from a total of 393 horses were collected. There were 61 animals from Salitre Valley (JUAZ-BA) located at Bahia state, 89 from North and Central North ecoregions located at Piauí state (NCEN-PI), 185 animals from Sertão and Sertão do São Francisco ecoregions (SERT-PE) and 58 animals from Agrestina city (AGRE-PE) located at Pernambuco state. Genetic diversity, genetic differentiation and bottleneck effects were examined in the 4 remnant subpopulations of Nordestino horse breed. There was high allelic diversity and the Fis value did not show evidence of a significant predominance of mating among relatives, probably because of crossbreeding among populations. Recent bottleneck effects were not detected in the 4 subpopulations, but the IAM and TPM model did suggest a bottleneck effect. This may be a reflection of the decreased number of breeding animals caused by castration of males, mechanization processes and changes in life style in the rural areas. The bottleneck event was not enough to lead a genetic differentiation among the 4 remnant subpopulations of Nordestino horse. There was no evidence of genetic differentiation, so the 4 subpopulations formed one genetic group.

O presente trabalho teve como objetivo avaliar a estrutura e diversidade genética de quatro subpopulações do cavalo Nordestino utilizando 14 marcadores microssatélites. Amostras de bulbo capilar de 393 cavalos foram coletadas, distribuídos em: 61 animais do vale do Salitre (JUAZ-BA) localizado no estado da Bahia, 89 das mesorregiões Norte e Centro-Norte do estado do Piauí, 58 animais da cidade de Agrestina (AGRE-PE) e 185 das mesorregiões Sertão e Sertão do São Francisco localizado no estado de Pernambuco (SERT-PE). A diversidade genética, diferenciação genética e efeito de gargalo genético foram avaliados nas 4 subpopulações do cavalo Nordestino. Observou-se elevada diversidade genética e valores de Fis que não evidenciaram níveis de consanguinidade significativa, provavelmente isso se deve à acasalamentos entre as subpopulações. Efeito de gargalo genético recente não foi detectado para as quatro subpopulações, porém os modelos IAM e TPM sugeriram um efeito de gargalo genético não recente. Isso pode ser reflexo da redução no número de reprodutores decorrente da castração de machos, processo de mecanização e mudanças no estilo de vida das populações da zona rural. Eventos mais antigos do efeito de gargalo genético não foram suficientes para evidenciar uma diferenciação genética entre as 4 subpopulações, portanto elas formam um só grupo genético.

In Greece, seven native horse breeds have been identified so far. Among these, the Skyros pony is outstanding through having a distinct phenotype. In the present study, the aim was to assess genetic diversity in this breed, by using different types of genetic loci and available genealogical information. Its relationships with the other Greek, as well as foreign, domestic breeds were also investigated. Through microsatellite and pedigree analysis it appeared that the Skyros presented a similar level of genetic diversity to the other European breeds. Nevertheless, comparisons between DNA-based and pedigree-based results revealed that a loss of genetic diversity had probably already occurred before the beginning of breed registration. Tests indicated the possible existence of a recent bottleneck in two of the three main herds of Skyros pony. Nonetheless, relatively high levels of heterozygosity and Polymorphism Information Content indicated sufficient residual genetic variability, probably useful in planning future strategies for breed conservation. Three other Greek breeds were also analyzed. A comparison of these with domestic breeds elsewhere, revealed the closest relationships to be with the Middle Eastern types, whereas the Skyros itself remained isolated, without any close relationship, whatsoever.

Genetic variation in Zemaitukai horses was investigated using mitochondrial DNA (mtDNA) sequencing. The study was performed on 421 bp of the mitochondrial DNA control region, which is known to be more variable than other sections of the mitochondrial genome. Samples from each of the remaining maternal family lines of Zemaitukai horses and three random samples for other Lithuanian (Lithuanian Heavy Draught, Zemaitukai large type) and ten European horse breeds were sequenced. Five distinct haplotypes were obtained for the five Zemaitukai maternal families supporting the pedigree data. The minimal difference between two different sequence haplotypes was 6 and the maximal 11 nucleotides in Zemaitukai horse breed. A total of 20 nucleotide differences compared to the reference sequence were found in Lithuanian horse breeds. Genetic cluster analysis did not shown any clear pattern of relationship among breeds of different type.

Examinou-se a variação genética de 102 cavalos Pantaneiros da região do Pantanal, Brasil, usando sete locos de grupos sanguíneos e 10 locos genéticos bioquímicos. As medidas de variação genética individual e diversidade genética populacional dentro da população de cavalos Pantaneiros foram próximas da média encontrada para as raças de cavalos domésticos. Do ponto de vista de conservação genética, não há preocupação imediata com relação à perda de variação dentro da raça. Análises das relações genéticas mostraram claramente que o cavalo Pantaneiro descende de cavalos da península Ibérica e que ele é estreitamente relacionado com as demais raças brasileiras.

Genetic variation at seven red blood cell alloantigen, blood group loci and 10 biochemical genetic loci was examined in 102 Pantaneiro horses from the Pantanal region of Brazil and compared to that of other domestic horse breeds. Measures of both individual genic variation and populational genetic diversity within the Pantaneiro were near the average for domestic horse breeds. From the standpoint of genetic conservation there is no immediate concern for loss of variation within the Pantaneiro. Analysis of genetic relationship showed that the Pantaneiro was clearly of Iberian Peninsula descent and that it was most closely related to other Brazilian breeds.