The combined application of next-generation sequencing platforms has provided an economical approach to unlocking the potential of the turkey genome.

A microsatellite-based high-density genetic map facilitates for fine mapping of hereditary traits of interest, characterization of meiosis, and providing a foundation for physical map construction. Here, we developed a comprehensive genetic map on the basis of >880,000 genotypes across the USDA MARC cattle reference families with a potential genetic resolution of 0.8 cM at the 95% confidence level (∼800 kb in the bovine genome). We incorporated 2325 microsatellites into the second-generation genetic map by linkage analysis based on sex-averaged two-point LOD scores (>3.0), of which 2293 were fine-mapped by multipoint linkage analysis. The new 3160-cM map comprised of 29 sex-averaged autosomal linkage groups and a sex-specific X-chromosome linkage group includes 3960 markers with 2389 positions, resulting in an average interval size of 1.4 cM. More than half (51%) of the total length of the map is covered with intervals of 2.0 cM or less, and the largest gap is a 10.2-cM interval on the X-linkage group. The new map should accelerate fine mapping and positional cloning of genes for genetic diseases and economically important traits in cattle, as well as related livestock species, such as sheep and goat.[Supplemental material is available online at www.genome.org. Marker information of new microsatellites is available from DDBJ under accession nos. AB164707 to AB166543 including flanking sequences and AB166544 to AB166659 for only primer sequences. Linkage groups for all autosomes and X-and Y-chromosomes are presented at

Paternal genome loss (PGL) during early embryogenesis is caused by two different genetic elements in the parasitoid wasp, Nasonia vitripennis. Paternal sex ratio (PSR) is a paternally inherited supernumerary chromosome that disrupts condensation of the paternal chromosomes by the first mitotic division of fertilized eggs. Bacteria belonging to the genus Wolbachia are present in Nasonia eggs and also disrupt paternal chromosome condensation in crosses between cytoplasmically incompatible strains. Cytoplasmic incompatibility Wolbachia are widespread in insects, whereas PSR is specific to this wasp. PGL results in production of male progeny in Nasonia due to haplodiploid sex determination. The cytological events associated with PGL induced by the PSR chromosome and by Wolbachia were compared by fluorescent light microscopy using the fluorochrome Hoescht 33258. Cytological examination of eggs fertilized with PSR-bearing sperm revealed that a dense paternal chromatin mass forms prior to the first metaphase. Quantification of chromatin by epifluorescence indicates that this mass does undergo replication along with the maternal chromatin prior to the first mitotic division but does not replicate during later mitotic cycles. Contrary to previous reports using other staining methods, the paternal chromatin mass remains condensed during interphase and persists over subsequent mitotic cycles, at least until formation of the syncytial blastoderm and cellularization, at which time it remains near the center of the egg with the yolk nuclei. Wolbachia-induced PGL shows several marked differences. Most notable is that the paternal chromatin mass is more diffuse and tends to be fragmented during the first mitotic division, with portions becoming associated with the daughter nuclei. Nuclei containing portions of the paternal chromatin mass appear to be delayed in subsequent mitotic divisions relative to nuclei free of paternal chromatin. Crosses combining incompatibility with PSR were cytologically similar to Wolbachia-induced PGL, although shearing of the paternal chromatin mass was reduced. Wolbachia may, therefore, block an earlier stage of paternal chromatin processing in the fertilized eggs than does PSR.

This review is a comprehensive introduction to the effects of poultry exposure to the toxic and carcinogenic mycotoxin aflatoxin B1 (AFB1). The relationship between AFB1 sensitivity and metabolism, major direct and indirect effects of AFB1, recent studies of gene expression and transcriptome responses to exposure, and mitigation strategies to reduce toxicity are discussed. Exposure to AFB1 primarily occurs by consumption of contaminated corn, grain or other feed components. Low levels of residual AFB1 in poultry feeds can cause reduction in growth, feed conversion, egg production, and compromised immune functions, resulting in significant economic costs to producers. Thus, AFB1 acts as a "force multiplier" synergizing the adverse effects of microbial pathogens and other agents, and factors detrimental to poultry health. Domestic turkeys (Meleagris gallopavo) are one of the most sensitive animals known to AFB1 due, in large part, to a combination of efficient hepatic bioactivation by cytochromes P450 1A5 and 3A37, and deficient hepatic glutathione-S-transferase (GST)-mediated detoxification. Because of their sensitivity, turkeys are a good model to investigate chemopreventive treatments and feed additives for their ability to reduce AFB1 toxicity. Transcriptome analysis (RNA-seq) of turkey poults (liver and spleen) has identified AFB1-induced gene expression changes in pathways of apoptosis, carcinogenesis, lipid regulation, antimicrobial activity, cytotoxicity and antigen presentation. Current research focuses on further identifying the molecular mechanisms OPEN ACCESSAgriculture 2015, 5 743 underlying AFB1 toxicity with the goal of reducing aflatoxicosis and improving poultry health.