Ex Situ Conservation Of Holstein-Friesian Cattle - Comparing The Dutch, French And USA Germplasm Collections

The establishment of gene banks using cryopreservation to secure the genetic diversity of farm breeds have been widely assessed. France, the Netherlands and the USA were among the first countries to organize national cryobanks and these banks are now 10 to 20 years old. All three countries have started Holstein-Friesian (HF) collections to conserve as much genetic diversity as possible for this globally important breed. In order better understand the diversity captured in these collections, the genetic variability of HF collections within and between countries was assessed, and genetic variability of germplasm collections were compared with active bulls in each country. The overall aim of the project was to determine the breed’s security and to guide future collection activities

Impact of the use of cryobank samples in a selected cattle breed: a simulation study

<p>Abstract</p> <p>Background</p> <p>High selection pressure on domestic cattle has led to an undesirable increase in inbreeding, as well as to the deterioration of some functional traits which are indirectly selected. Semen stored in a cryobank may be a useful way to redirect selection or limit the loss of genetic diversity in a selected breed. The purpose of this study was to analyse the efficiency of current cryobank sampling methods, by investigating the benefits of using cryopreserved semen in a selection scheme several generations after the semen was collected.</p> <p>Methods</p> <p>The theoretical impact of using cryopreserved semen in a selection scheme of a dairy cattle breed was investigated by simulating various scenarios involving two negatively correlated traits and a change in genetic variability of the breed.</p> <p>Results</p> <p>Our results indicate that using cryopreserved semen to redirect selection will have an impact on negatively selected traits only if it is combined with major changes in selection objectives or practices. If the purpose is to increase genetic diversity in the breed, it can be a viable option.</p> <p>Conclusions</p> <p>Using cryopreserved semen to redirect selection or to improve genetic diversity should be carried out with caution, by considering the pros and cons of prospective changes in genetic diversity and the value of the selected traits. However, the use of genomic information should lead to more interesting perspectives to choose which animals to store in a cryobank and to increase the value of cryobank collections for selected breeds.</p

Genetic diversity of a large set of horse breeds raised in France assessed by microsatellite polymorphism

After the recent publication of our article (Leroy, Genetics Selection Evolution 2009 41:5), we found several errors in the published Table Three, concerning the computation of contribution to within-breed diversity (CW). We apologize to the readers for these errors, which are corrected in the present erratum

A comprehensive analysis of the genetic diversity and environmental adaptability in worldwide Merino and Merino-derived sheep breeds

BACKGROUND: To enhance and extend the knowledge about the global historical and phylogenetic relationships between Merino and Merino-derived breeds, 19 populations were genotyped with the OvineSNP50 BeadChip specifically for this study, while an additional 23 populations from the publicly available genotypes were retrieved. Three complementary statistical tests, Rsb (extended haplotype homozygosity between-populations), XP-EHH (cross-population extended haplotype homozygosity), and runs of homozygosity (ROH) islands were applied to identify genomic variants with potential impact on the adaptability of Merino genetic type in two contrasting climate zones. RESULTS: The results indicate that a large part of the Merino's genetic relatedness and admixture patterns are explained by their genetic background and/or geographic origin, followed by local admixture. Multi-dimensional scaling, Neighbor-Net, Admixture, and TREEMIX analyses consistently provided evidence of the role of Australian, Rambouillet and German strains in the extensive gene introgression into the other Merino and Merino-derived breeds. The close relationship between Iberian Merinos and other South-western European breeds is consistent with the Iberian origin of the Merino genetic type, with traces from previous contributions of other Mediterranean stocks. Using Rsb and XP-EHH approaches, signatures of selection were detected spanning four genomic regions located on Ovis aries chromosomes (OAR) 1, 6 and 16, whereas two genomic regions on OAR6, that partially overlapped with the previous ones, were highlighted by ROH islands. Overall, the three approaches identified 106 candidate genes putatively under selection. Among them, genes related to immune response were identified via the gene interaction network. In addition, several candidate genes were found, such as LEKR1, LCORL, GHR, RBPJ, BMPR1B, PPARGC1A, and PRKAA1, related to morphological, growth and reproductive traits, adaptive thermogenesis, and hypoxia responses. CONCLUSIONS: To the best of our knowledge, this is the first comprehensive dataset that includes most of the Merino and Merino-derived sheep breeds raised in different regions of the world. The results provide an in-depth picture of the genetic makeup of the current Merino and Merino-derived breeds, highlighting the possible selection pressures associated with the combined effect of anthropic and environmental factors. The study underlines the importance of Merino genetic types as invaluable resources of possible adaptive diversity in the context of the occurring climate changes

A controversy about crossbreeding in a conservation programme : the case study of the Flemish red cattle breed

The aim of this paper was to understand the complexity of a conservation programme of a local breed by linking genetic and social data. This approach is illustrated by the case of the Flemish Red cattle breed, which has been crossbred since the 1950s, mainly with the Danish Red breed. Farmers and other people involved in the management of this breed were interviewed about breeding goals and practices. The genetic variability of the breed and the genetic impact of crossbreeding were assessed via pedigree data. The opportunity to use crossbreeding was found to be the main controversy, if not the only one, among the different institutional stakeholders involved in the management of the breed. However, the farmers said that they attributed little importance to the proportion of Danish Red genes in the AI bull genome. From the pedigree analysis, the proportion of Danish Red genes in the Flemish Red breed was found to increase from the early 1970s to the early 1980s and to then stabilise around an average value of 28%. The proportion of Flemish Red cows with no Danish Red genes in their genome decreased regularly and became null in the early 2000s. More than 90% of the Flemish Red cows born at that time had a proportion of Danish Red genes ranging from 1/8 to 1/2. The Danish Red genes were found to mainly originate from crossbred bulls and not from pure Danish Red bulls. This paper focuses on the nature of the gene pool preserved in such a case, and the need to clearly define the goals of conservation programmes is highlighted