Abstract
Abstract. Beta-lactoglobulin (LGB) and the Welsh αS1-casein (αS1-casein D) types have been determined using PCR-RFLP tests in DNA isolated from blood samples collected from four dairy sheep breeds (Awassi, British Milk Sheep, Tsigaia, Lacaune), from Hungarian Merinos and from various crossbreeds (AwassixMerino) F1, (MerinoxLanghe) F1, (MerinoxPleven Blackhead) F1, (MerinoxPleven Blackhead ) F1x Black East Friesian). The following LGBA frequency values have been obtained: Awassi 0.3478; British Milk Sheep 0.6857; Tsigaia 0.5650; Lacaune 0.4730; Hungarian Merino 0.6767; (Awassix Merino) F1 0.4694; (MerinoxLanghe) F1 0.7777; (MerinoxPleven Blackhead) F1 0.5945; (MerinoxPleven Blackhead) F1 x Black East Friesian 0.6026. The Welsh αS1-casein variant was found in the Hungarian Merino breed only (4 homozygous and 16 heterozygous ewes). Plans for studies on the possible effects of these milk protein types, on milk yield and composition as well as on cheese making properties ofmilk and cheese yields are outlined.
Highlights
LGB is the major whey protein in sheep milk
1607 blood samples have been collected from different sheep breeds existing in Hungary such as Awassi, British Milksheep, Tsigaia, Lacaune, Hungarian Merino and their crosses
Blood samples have been stored at -20°C until DNA extraction LGB types and the With reference to asl-casein only the D (Welsh) variant were determined by PCR-RFLP assay All chemicals were purchased from Promega (Madison, Wi, USA ) unless indicated otherwise
Summary
LGB is the major whey protein in sheep milk. KOLDE and BRAUNITZER (1983) described the difference between variants A and B at amino-acid position 20, where variant A has His while variant B has Thr. ERHARDT (1989) and RECIO et al (1995) evidenced a third variant ( C ) at the LGB locus in German Merinoland and Spanish Merino sheep by isoelectric focusing. SCHLEE et al (1993) detected in DNA the same polymorphism described already in milk by amplifying a DNA fragment of intron I and exon I of LGB by PCR. PRINZENBERG and ERHARDT (1999) and ANTON et al (1999) developed a PCRRFLP typing procedure using Mspl and Alu I for the detection of both mutations (alleles A, B and C). CHIANESE et al (1996) detected five variants of aS)-casein (A, B, C, D and E)
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