Chromosomal regions underlying noncoagulation of milk in Finnish Ayrshire cows.

About 10% of Finnish Ayrshire cows produce noncoagulating milk, i.e., milk that does not form a curd in a standard 30-min testing time and is thus a poor raw material for cheese dairies. This phenomenon is associated with peak and midlactation, but some cows produce noncoagulating milk persistently. A genomewide scan under a selective DNA pooling method was carried out to locate genomic regions associated with the noncoagulation of milk. On the basis of the hypothesis of the same historical mutation, we pooled the data across sires. Before testing pools for homogeneity, allele intensities were corrected for PCR artifacts, i.e., shadow bands and differential amplification. Results indicating association were verified using daughter design and selective genotyping within families. Data consisted of 18 sire families with 477 genotyped daughters in total, i.e., 12% of each tail of the milk coagulation ability. Data were analyzed using interval mapping under maximum-likelihood and nonparametric methods. BMS1126 on chromosome 2 and BMS1355 on chromosome 18 were associated with noncoagulation of milk across families on an experimentwise 0.1% significance level. By scanning gene databases, we found two potential candidate genes: LOC538897, a nonspecific serine/threonine kinase on chromosome 2, and SIAT4B, a sialyltransferase catalyzing the last step of glycosylation of kappa-casein on chromosome 18. Further studies to determine the role of the candidates in the noncoagulation of milk are clearly needed.

A new SBP-box gene BpSPL1 in silver birch (Betula pendula).

The SBP-box gene family represents a group of plant-specific genes encoding putative transcription factors. Thus far, SBP-domain protein binding sites have been found in the promoters of Arabidopsis APETALA1 and Antirrhinum SQUAMOSA. A putative SBP-domain binding element has been observed in the promoter of BpMADS5, a close homologue of Arabidopsis FRUITFULL in silver birch (Betula pendula). A novel SBP-box gene from birch named BpSPL1 has been cloned and characterized. The nucleotide sequence of BpSPL1 is similar to Antirrhinum SBP2 and Arabidopsis SPL3, apart from the unique finding that BpSPL1 does not contain an intron typical to all other known SBP-box genes studied thus far. According to Northern blot analysis, BpSPL1 is expressed in birch inflorescences as well as in shoots and leaves. Studies using electrophoretic mobility shift assay demonstrate that there are nuclear proteins in birch inflorescences which specifically bind to the SBP binding element of the promoter of BpMADS5. BpSPL1 expressed in Escherichia coli also specifically binds to this element. According to Southern blot analysis, there are at least two SBP-box genes in birch. The results suggest that SBP-box genes are involved in the regulation of flower development in birch.