AUTHOR=Meier Saskia , Korkuć Paula , Arends Danny , Brockmann Gudrun A. 

TITLE=DNA Sequence Variants and Protein Haplotypes of Casein Genes in German Black Pied Cattle (DSN)

JOURNAL=Frontiers in Genetics

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2019.01129

DOI=10.3389/fgene.2019.01129

ISSN=1664-8021

ABSTRACT=<p>Casein proteins were repeatedly examined for protein polymorphisms and frequencies in diverse cattle breeds. The occurrence of casein variants in Holstein Friesian, the leading dairy breed worldwide, is well known. The frequencies of different casein variants in Holstein are likely affected by selection for high milk yield. Compared to Holstein, only little is known about casein variants and their frequencies in German Black Pied cattle (“Deutsches Schwarzbuntes Niederungsrind,” DSN). The DSN population was a main genetic contributor to the current high-yielding Holstein population. The goal of this study was to investigate casein (protein) variants and casein haplotypes in DSN based on the DNA sequence level and to compare these with data from Holstein and other breeds. In the investigated DSN population, we found no variation in the alpha-casein genes <italic>CSN1S1</italic> and <italic>CSN1S2</italic> and detected only the <italic>CSN1S1*B</italic> and <italic>CSN1S2*A</italic> protein variants. For <italic>CSN2</italic> and <italic>CSN3</italic> genes, non-synonymous single nucleotide polymorphisms leading to three different β and κ protein variants were found, respectively. For β-casein protein variants <italic>A</italic><italic><sup>1</sup></italic>, <italic>A</italic><italic><sup>2</sup></italic>, and <italic>I</italic> were detected, with <italic>CSN2*A</italic><italic><sup>1</sup></italic> (82.7%) showing the highest frequency. For κ-casein protein variants <italic>A</italic>, <italic>B</italic>, and <italic>E</italic> were detected in DSN, with the highest frequency of <italic>CSN3*A</italic> (83.3%). Accordingly, the casein protein haplotype <italic>CSN1S1*B-CSN2*A</italic><italic><sup>1</sup></italic>-<italic>CSN1S2*A</italic>-<italic>CSN3*A</italic> (order of genes on BTA6) is the most frequent haplotype in DSN cattle.</p>