M.Z. Siwek

Identification of QTLs Involved in Open-Field Behavior in Young and Adult Laying Hens

Line differences for open-field behavior in chickens have been observed, and it has been shown that this behavior has a genetic component. The aim of this study was to detect quantitative trait loci (QTL) involved in open-field behavior. For this purpose, open-field behavior was studied at 5 and 29 weeks of age in F2 hens coming from an intercross between two commercial White Leghorn laying lines selected for egg production traits. Latencies, durations, and frequencies of general activity (sitting, standing, walking, and stepping), defecation, and vocalizations were recorded individually for each bird, and a factor score was calculated. All animals (F0, F1, and F2) were screened with 180 microsatellite markers. Regression interval mapping was applied using both a paternal half-sib analysis and a line-cross analysis method. For general activity at 5 weeks of age, a significant QTL was detected on GGA4 and a suggestive QTL on GGA2 under the line-cross model. For general activity at 29 weeks of age, a significant QTL was detected on GGA4 and two suggestive QTLs were detected on GGA1 and on GGA10, respectively, also using the line-cross analysis. The QTL on GGA4 at 5 weeks of age did not overlap with the QTL on GGA4 at 29 weeks of age. The current study indicated that open-field behavior in young chickens was regulated by QTL that differ from the QTL for open-field behavior in adult chickens.

Parental reconstruction in rural goat population with microsatellite markers

Proper knowledge about individual origin and pedigree is a major point for animal breeding and livestock genetic improvement. Mainly for goat, but also for sheep breeding in Sicily information on these points is limited, and sometimes even misleading. Goat milk production is, in many regions and especially in Sicily, a rural enterprise, where males and females graze together and pedigree of offspring can be largely unknown. Genetic improvement in this situation is challenging. Modern DNA techniques can help to identify the parentage (PI, parental identification). In this paper we discuss: i) our set of microsatellites markers in relation to the ECONOGENE set; ii) accuracy of microsatellite genotyping for a goat breed; iii) the principle of verification and identification as tested on one goat breeding farm; iv) direct use of the technique in a running goat breeding program. For a practical application we suggest the use of around 20 quality microsatellite markers, and the use of primiparous milk analysis. In our data set originating from one farm (184 records) for parental verification 17% parent pairs were considered erratic. Parental identification allowed for successful assignment of 49 parent pairs.

Genetic Aspects of Biological Processes Underlying the Defense System in the Neonate

(Suppl.): 39-43.Preparation for postnatal life of a neonate is determined by (1) adequate pre-nataldevelopment (2) development of innate immunity and (3) transfer of maternal antibodies. Inthis contribution the trait “piglet survival” will be explored using quantitative methods,searching for genetic variation and for biological explanations for possible geneticdifferences in piglet survival. Whereas for the chicken “ innate immune system defined asnatural antibodies (NAbs)” will be explored using a genomic approach searching forQuantitative Trait Loci (QTL) in an F2 cross of chicken lines selected for high and lowantibodyresponsestoSRBC(SheepRedBloodCells).Byrevealingvariationwhichunderliebiological processes of neonates it is shown that the defense system of the neonate is undergenetic control. Genes of the neonate influence its innate defense system, taking care ofgeneral defense and of adaptation possibilities to novel antigens. The genes of the dam help,throughmaternalantibodies, tosurvivethroughtheearlydaysoflife.Wefindthattheinnatedefense system can be improved through direct selection against mortality and that thesystem of natural antibodies might have single gene variation, worthy of furtherinvestigation.Key words: chicken, piglet, natural antibodies, mortality, Quantitative Trait Loci, quantitativeapproach.