RESUMO
BACKGROUND: The turkey (Meleagris gallopavo) is an important agricultural species and the second largest contributor to the world's poultry meat production. Genetic improvement is attributed largely to selective breeding programs that rely on highly heritable phenotypic traits, such as body size and breast muscle development. Commercial breeding with small effective population sizes and epistasis can result in loss of genetic diversity, which in turn can lead to reduced individual fitness and reduced response to selection. The presence of genomic diversity in domestic livestock species therefore, is of great importance and a prerequisite for rapid and accurate genetic improvement of selected breeds in various environments, as well as to facilitate rapid adaptation to potential changes in breeding goals. Genomic selection requires a large number of genetic markers such as e.g. single nucleotide polymorphisms (SNPs) the most abundant source of genetic variation within the genome. RESULTS: Alignment of next generation sequencing data of 32 individual turkeys from different populations was used for the discovery of 5.49 million SNPs, which subsequently were used for the analysis of genetic diversity among the different populations. All of the commercial lines branched from a single node relative to the heritage varieties and the South Mexican turkey population. Heterozygosity of all individuals from the different turkey populations ranged from 0.17-2.73 SNPs/Kb, while heterozygosity of populations ranged from 0.73-1.64 SNPs/Kb. The average frequency of heterozygous SNPs in individual turkeys was 1.07 SNPs/Kb. Five genomic regions with very low nucleotide variation were identified in domestic turkeys that showed state of fixation towards alleles different than wild alleles. CONCLUSION: The turkey genome is much less diverse with a relatively low frequency of heterozygous SNPs as compared to other livestock species like chicken and pig. The whole genome SNP discovery study in turkey resulted in the detection of 5.49 million putative SNPs compared to the reference genome. All commercial lines appear to share a common origin. Presence of different alleles/haplotypes in the SM population highlights that specific haplotypes have been selected in the modern domesticated turkey.
Assuntos
Variação Genética , Polimorfismo de Nucleotídeo Único , Perus/genética , Animais , Cruzamento , Biblioteca Gênica , Masculino , México , Filogenia , Análise de Sequência de DNARESUMO
The diversity in todays livestock breeds has been shaped largely through the domestication of wild ancestral species and subsequent refinement by human selection for desired traits. Only a small fraction of the genetic diversity from the ancestral species survives in the domestic counterparts. A 2007 report released by UN Food and Agriculture Organization (FAO) "The state of the world's animal genetic resources" stated that nearly 70% of the world's remaining livestock breeds are found in developing countries, while the developed countries are characterized by a few highly productive breeds that thrive under intensive farming systems. The indigenous livestock breeds in developing countries are increasingly at risk as non-native breeds are imported to replace and/or cross-breed in an attempt to improve productivity. The First International Technical Conference on Animal Genetic Resources in Interlaken, Switzerland brought together more than 300 policy makers, scientists, breeders, and livestock keepers with the aim of developing a global plan of action for conserving animal genetic resources as its main outcome. In this paper, the impact of diminishing genetic diversity on livestock breeds and the development of genetic resource banks as insurance against the loss of livestock genetic diversity are considered. (AU)
Assuntos
Animais , Criação de Animais Domésticos/economia , Criação de Animais Domésticos/éticaRESUMO
The diversity in todays livestock breeds has been shaped largely through the domestication of wild ancestral species and subsequent refinement by human selection for desired traits. Only a small fraction of the genetic diversity from the ancestral species survives in the domestic counterparts. A 2007 report released by UN Food and Agriculture Organization (FAO) "The state of the world's animal genetic resources" stated that nearly 70% of the world's remaining livestock breeds are found in developing countries, while the developed countries are characterized by a few highly productive breeds that thrive under intensive farming systems. The indigenous livestock breeds in developing countries are increasingly at risk as non-native breeds are imported to replace and/or cross-breed in an attempt to improve productivity. The First International Technical Conference on Animal Genetic Resources in Interlaken, Switzerland brought together more than 300 policy makers, scientists, breeders, and livestock keepers with the aim of developing a global plan of action for conserving animal genetic resources as its main outcome. In this paper, the impact of diminishing genetic diversity on livestock breeds and the development of genetic resource banks as insurance against the loss of livestock genetic diversity are considered.