Short communication: duplication in the 5'-flanking region of the beta-lactoglobulin gene is linked to the BLG A allele.
beta-Lactoglobulin (beta-LG) is the major whey protein in the milk of cows and other ruminants. It is well established that the predominant genetic variants beta-LG A and B are differentially expressed. Extensive investigation of the genetic variation in the promoter region of the BLG gene revealed the existence of specific haplotypes associated with the A and B variants. However, the genetic basis for the differentially expressed BLG A and B alleles is still elusive. In this study additional genetic variation further upstream in the 5'-flanking region of the BLG gene was identified, including 6 single nucleotide substitutions, a single nucleotide deletion, and a 7-bp duplication. Comparison of DNA sequences showed that the investigated 5'-flanking region is highly conserved between ruminants, and the duplication g.-1885_-1879dupCTCTCGC and the substitution g.-1888A>G are only found in the BLG A and D alleles in cattle. The cytosine at position g.-1957 and the thymines at positions g.-2008 and g.-2049 are only found in BLG B alleles of cattle. It is suggested that the described genetic variability contributes to the differential allelic expression of the BLG gene.
Braunschweig
M H
MH
Institute of Genetics, University of Berne, CH-3001 Berne, Switzerland. martin.braunschweig@itz.unibe.ch
D024506:5' Flanking Region / Q000235:genetics*; D000483:Alleles; D000818:Animals; D001483:Base Sequence; D002417:Cattle / Q000235:genetics* / Q000502:physiology; D005260:Female; D020440:Gene Duplication; D015870:Gene Expression; D014644:Genetic Variation; D007782:Lactoglobulins / Q000235:genetics*; D011401:Promoter Regions, Genetic
D007782:Lactoglobulins