Polymorphism of three milk protein genes in Mexican Jersey cattle

Abstract

The objective was to estimate the allelic and genotypic frequencies, genetic diversity and polymorphic information content for the β-casein, κ-casein and β-lactoglobulin genes. Blood and frozen semen samples were collected from 453 Jersey individuals registered by the Mexican Jersey Cattle Association. Twenty eight breed specific SNP primers for whole genes were used. The B allele of κ-casein had higher frequency (0.69) than the A (0.26) and E (0.05). For β-lactoglobulin, the highest frequency was for B (0.72), followed by A and C alleles (0.26 and 0.02, respectively). The β-casein allele with the highest frequency was A 2 (0.71), followed by A 1 (0.19), A 3 (0.05), B (0.04) and C (0.01). The average genetic diversity (He) was 0.53. The average locus effective allele number was 1.79. These results indicate a high allelic diversity for κ-caseín, β-casein and β-lactoglobulin that could be included in breeding programs in the population studied, aimed to improve the milk quality traits of economic importance.

Polymorphism in the Beta Casein Gene and analysis of milk characteristicsin Gir and Guzerá dairy cattle

“…In analyzing the frequency of heterozygotes among breeds, we observed that Guzerá animals had a higher amount of heterozygous animals, being approximately 6.82% (6 animals) compared to Gir, which had 4.41% (3 animals) of the population (Table 1). None of the evaluated animals presented homozygosity for A1, due to Zebu breeds presenting higher frequency of A2 allele compared to taurine breeds (Zepeda-Batista et al, 2015;Silva, 2016). According to Silva (2016), as Brazil has animals originating from absorbent crossbreeding, pure breed animals generated by these crossings have the mitochondrial DNA of taurine origin, which may have caused the presence of A1 allele at a low frequency in Zebu breeds.…”

Polymorphism, Allelic and Genotypic Frequencies of κ-Casein and β-LG genes in Egyptian Buffaloes

“…Several authors estimated expected and observed heterozygosity to identify the genetic variability for κ-CN gene in different cattle breeds and reported that the observed heterozygotes of κ-CN gene were significantly differ from the expected one, i.e., some cattle breeds had a heterozygote excess as reported by Sulimova et al (2007) who found that most of Russian cattle breeds had a heterozygote excess with H o ranged from (0.0.27 to 0.60) and H e ranged from (0.26 to 0.50), as well as, Zepeda-Batista et al (2015) found that the Mexican Jersey cattle showed differences (P < 0.05) between observed (H o = 0.50) and expected (H e = 0.45) heterozygosity, These results indicated a high allelic diversity for κ-CN that could be included in breeding programs in the population studied, aimed to improve the milk quality traits of economic importance. Mohammadi et al (2013) reported that the observed heterozygotes of κ-CN gene were extremely lower than the expected one in Iranian Holstein cattle with H o value of (0.18) and H e value of (0.31).…”

The Polymorphism in Various Milk Protein Genes in Polish Holstein-Friesian Dairy Cattle

“…Sebastiani et al [ 2 ] also stated that no deviation from equilibrium was detected in their study. Literature, however, provides a description of studies in which observed and expected heterozygosity significantly differed ( p < 0.05) confirming that the population was not in H-W equilibrium [ 19 ]. Such results may suggest that in the studied population management focusing on reproduction and genetic improvement might have been applied.…”

“…Therefore, if any population is proven to be out of Hardy–Weinberg equilibrium, it may suggest that some kind of evolutionary process may affect the population. Deviation from H-W equilibrium may be also an indicator that matings in the herd were planned favoring one of the genotypes [ 19 ].…”