Molecular and pedigree analysis applied to conservation of animal genetic resources: the case of Brazilian Somali hair sheep

• Published in: Tropical animal health and production 2011-10, Vol.43 (7), p.1449-1457
• Main Authors: Paiva, Samuel R., Facó, Olivardo, Faria, Danielle A., Lacerda, Thaísa, Barretto, Gabriel B., Carneiro, Paulo L. S., Lobo, Raimundo N. B., McManus, Concepta
• Format: Article
• Language: English
• Subjects: Animals; Base pairs; Base Sequence; Biomedical and Life Sciences; Brazil; Breeding; Climate; Conservation; Conservation of Natural Resources - methods; Dietary restrictions; DNA, Mitochondrial - genetics; Food supply; Genetic diversity; Genetic markers; Genetic Markers - genetics; Genetic resources; Genetic Variation; Genetics, Population; Genotype; Genotyping; Hair; Haplotypes; Heterozygosity; Inbreeding; Inbreeding - statistics & numerical data; Life Sciences; Microsatellite Repeats - genetics; Microsatellites; Mitochondrial DNA; Molecular Sequence Data; Nuclei; Pedigree; Sequence Alignment; Sheep; Sheep, Domestic - genetics; SI Fat Tailed Sheep; Veterinary Medicine/Veterinary Science; Wildlife conservation; Zoology
• ISSN: 0049-4747; 1573-7438
• DOI: 10.1007/s11250-011-9873-6

The first registers of Somali sheep in Brazil are from the beginning of the 1900s. This breed, adapted to the dry climate and scarce food supply, is restricted in the northeast region of the country. Molecular marker technologies, especially those based on genotyping microsatellite and mtDNA loci, can be used in conjunction with breeding (pedigree analysis) and consequently the maintenance of genetic variation in herds. Animals from the Brazilian Somali Conservation Nuclei from Embrapa Sheep and Goats in Ceará State were used to validate genetic monitoring by traditional pedigree methods and molecular markers. Nineteen microsatellite markers and 404 base pairs from the control region of mtDNA were used. For total herd diversity, an average 5.32 alleles were found, with expected heterozygosity of 0.5896, observed heterozygosity of 0.6451, 0.4126 for molecular coancestrality, and coefficient of inbreeding ( F IS ) was −0.095. Comparing molecular coancestrality means over the years, there was a consistent increase in this parameter within the herd, increasing from 0.4157 to 0.4769 in 2 years (approx. 12% variation). Sixteen mtDNA haplotypes were identified. Inbreeding and other estimates from genealogical analyses confirm the results from molecular markers. From these results, it is possible to state that microsatellites are useful tools in genetic management of herds, especially when routine herd recording is not carried out, or there were gaps in recent generations. As well as pedigree control, genetic diversity can be optimized. Based on the results, and despite herd recording in the herd of Brazilian Somali of Embrapa Sheep and Goats, additional management measures need to be carried out in this herd to reduce inbreeding and optimize genetic variation.