No abstract

The gene for agouti signaling protein (ASIP) is centrally involved in the expression of coat color traits in animals. The Mangalitza pig breed is characterized by a black-and-tan phenotype with black dorsal pigmentation and yellow or white ventral pigmentation. We investigated a Mangalitza x Piétrain cross and observed a coat color segregation pattern in the F2 generation that can be explained by virtue of two alleles at the MC1R locus and two alleles at the ASIP locus. Complete linkage of the black-and-tan phenotype to microsatellite alleles at the ASIP locus on SSC 17q21 was observed. Corroborated by the knowledge of similar mouse coat color mutants, it seems therefore conceivable that the black-and-tan pigmentation of Mangalitza pigs is caused by an ASIP allele a(t), which is recessive to the wild-type allele A. Toward positional cloning of the a(t) mutation, a 200-kb genomic BAC/PAC contig of this chromosomal region has been constructed and subsequently sequenced. Full-length ASIP cDNAs obtained by RACE differed in their 5' untranslated regions, whereas they shared a common open reading frame. Comparative sequencing of all ASIP exons and ASIP cDNAs between Mangalitza and Piétrain pigs did not reveal any differences associated with the coat color phenotype. Relative qRT-PCR analyses showed different dorsoventral skin expression intensities of the five ASIP transcripts in black-and-tan Mangalitza. The a(t) mutation is therefore probably a regulatory ASIP mutation that alters its dorsoventral expression pattern.

Anal atresia is a rare and severe disorder in swine occurring with an incidence of 0.1-1.0%. A wholegenome scan based on affected half-sibs was performed to identify susceptibility loci for anal atresia. The analysis included 27 families with a total of 95 animals and 65 affected piglets among them. Animals were genotyped for 126 microsatellite markers distributed across the 18 autosomal porcine chromosomes and the X chromosome, covering an estimated 2080 cM. Single-point and multipoint nonparametric linkage scores were calculated using the computer package ALLEGRO 1.0. Significant linkage results were obtained for chromosomes 1, 3, and 12. Markers on these chromosomes and additionally on chromosomes for which candidate genes have been postulated in previous studies were subjected to the transmission disequilibrium test (TDT). The test statistic exceeded the genomewide significance level for adjacent markers SW1621 (P ¼ 7 3 10 ÿ7 ) and SW1902 (P ¼ 3 3 10 ÿ3 ) on chromosome 1, supporting the results of the linkage analysis. A specific haplotype associated with anal atresia that could prove useful for selection against the disorder was revealed. Suggestive linkage and association were also found for markers S0081 on chromosome 9 and SW957 on chromosome 12.

SummaryA total of 345 F 2 animals from a crossbred design Mangalitza (homozygous NN) x Piettain (homozygous nn) were fed ad libitum at the institute's Thalhausen Research Station and slaughtered at a live weight of approximately 100 kg. MHS genotypes (67 nn, 192 Nn and 86 NN) were determined directly in a DNA test targeting the ryanodine reeeptor locus. Models for analysis of variance included sire, dam, pen, slaughter group, sex and MHS effects. Growth Performance was generally lower and carcass composition minor compared to other breeds and crosses. No significant differences were found between MHS genotypes for growth traits but NN animals tended to be less eflicient with respect to food conversion. However, nearly all measurements of the carcass showed significant differences between nn and NN which were especially pronounced for sidefat thickness (-7 1mm) fat over the musculus longissimus dorsi (-8.8 mm) and loin eye area (+8.7 cm 2 ) as well as fat area (-5.1 cm 2 ) We found Nn animals performing similar to NN animals due to incomplete dominance of the N allele. As expected nn had a substantial negative influence on meat quality compared to NN and Nn (e.g. -0.61 and -0.15 for pH 45 min, respectively). Intramuscular fat content was at a high level and nn had significantly lower values with differences of-0.40 % and -0.25 % relative to NN and Nn, respectively. A whole genome scan is currently underway with emphasis on fat measurements which showed promising Variation in this study.Key Words: swine, Mangalitza x Pietrain, growth, carcass, meat quality, MHS Zusammenfassung Titel der Arbeit: Einfluss des MHS-Gens auf die Merkmale Mastleistung, Schlachtleistung und Fleischbeschaffenheit von F 2 Kreuzungstteren der Rassen Mangalitza und Pietrain 345 F 2 Kreuzungstiere der Rassen Mangalitza (homozygot NN) und Pietrain (homozygot nn) wurden in der dem Lehrstuhl zugehörigen Versuchsstation Thalhausen ad libitum gefüttert und mit einem Lebendgewicht von etwa 100 kg geschlachtet. Die MHS Genotypen (67 nn, 192 Nn, 86 NN) wurden gendiagnostisch am Ryanodinrezeptor bestimmt. Als Einflussfaktoren wurden im statistischen Modell der Eber, die Sau, die Mastgruppe der Schlachttag/Schlachtort, das Geschlecht und der MHS Status berücksichtigt. Die Mast-und Schlachtleistungen waren im Vergleich zu anderen Rassen und Kreuzungen auf einem niedrigen Niveau. Hinsichtlich der Mastleistung wurden keine signifikanten Unterschiede zwischen den MHS Genotypen ermittelt, obwohl NN Tiere tendenziell schlechter abschnitten. Hingegen wurden bei fast allen Schlachtleistungsmerkmalen deutliche Unterschiede zwischen den MHS Genotypen nn und NN festgestellt, die bei der Seitenspeckdicke (-7,1mm) und dem Speckmaß B (-8,8 mm) sowie der Kotelett -(+8,7 cm 2 ) und der Fettfläche (-5,1 cm 2 ) besonders stark ausgeprägt waren. Nn-Tiere lagen eher im Bereich der NN Tiere und meist lässt sich zumindest auf partielle Dominanz des N-Allels schließen. Erwartungsgemäß verschlechterte der nn Genotyp die Fleischqualität, verglichen zu NN und Nn, erheblich (-0...