LXRα gene expression, genetic variation and association analysis between novel SNPs and growth traits in Chinese native cattle

LEP and SCD polymorphisms are associated with milk somatic cell count, electrical conductivity and pH values in Holstein cows

This study was conducted to determine LEP-Sau3AI, SCD-Fnu4HI, NR1H3-HpyCH4IV and FABP4-HinII gene polymorphisms and to investigate the association between these SNPs and somatic cell count (SCC), electrical conductivity (EC) and pH in Holstein cow milk. LEP-Sau3AI polymorphism found associated with SCC (p < 0.01), EC (p < 0.01) and pH (p < 0.05). LEP-Sau3AI-BB genotype resulted with higher SCC, EC and pH compared to other genotypes. SCD-Fnu4HI polymorphism showed differences in genotypes for EC (p < 0.05) and pH (p ≤ 0.05) traits. While the highest EC value was found in SCD-Fnu4HI-CT genotype, the highest milk pH was found in genotype TT. In addition, NR1H3-HpyCH4IV genotypes was found the only associated with pH (p < 0.05) among all studied phenotypes. Based on the present findings, it was concluded that LEP and SCD genes could be used in breeding programs for improved SCC, EC and pH values in Holstein dairy cows.

Two Novel SNPs of PPARγ Significantly Affect Weaning Growth Traits of Nanyang Cattle

Peroxisome-proliferator-activated receptor gamma (PPARγ) is a key transcription factor that controls adipocyte differentiation and energy in mammals. Therefore, PPARγ is a potential factor influencing animal growth traits. This study primarily evaluates PPARγ as candidate gene for growth traits of cattle and identifies potential molecular marker for cattle breeding. Per previous studies, PPARγ mRNA was mainly expressed at extremely high levels in adipose tissues as shown by quantitative real-time polymerase chain reaction analysis. Three novel SNPs of the bovine PPARγ gene were identified in 514 individuals from six Chinese cattle breeds: SNP1 (AC_000179.1 g.57386668 C > G) in intron 2 and SNP2 (AC_000179.1 g.57431964 C > T) and SNP3 (AC_000179.1 g.57431994 T > C) in exon 7. The present study also investigated genetic characteristics of these SNP loci in six populations. Association analysis showed that SNP1 and SNP3 loci significantly affect weaning growth traits, especially body weight of Nanyang cattle. These results revealed that SNP1 and SNP3 are potential molecular markers for cattle breeding.

Polymorphisms in MX2 Gene Are Related with SCS in Chinese Dairy Cows

Viral infections can play direct or indirect roles in the etiology of the bovine mastitis. Mx dynamin-like GTPase 2 (MX2) gene is a main effector of the antiviral innate immune defense mediated by type I interferon (IFN I), which was demonstrated to confer positive antiviral responses to many viruses. Given the importance of the MX2 in modulating the host immune response, MX2 gene may be a suitable candidate gene for studying disease resistance in dairy cattle. Here, we scanned the sequence variation of the MX2 gene in Chinese indigenous cattle breeds. Twenty-three previously reported SNPs were identified. To further analyze the effects of SNPs detected on mastitis disease, analysis of two SNPs (g.787527 C > T and g.787610 T > C) from 297 Chinese Holstein cows revealed a significant association with somatic cell score (SCS). Although functional studies are necessary to ascertain whether these two SNPs are causal polymorphisms or merely in linkage with the true causal SNPs, implementation of these two SNPs as genetic markers in the dairy industry may be beneficial in selecting individuals with lower SCS.